xref: /dports/databases/percona56-client/percona-server-5.6.51-91.0/storage/rocksdb/ha_rocksdb.cc

/*
   Copyright (c) 2012, Monty Program Ab

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif

#define MYSQL_SERVER 1

/* The C++ file's header */
#include "./ha_rocksdb.h"

/* C++ standard header files */
#include <algorithm>
#include <queue>
#include <set>
#include <string>
#include <vector>

/* MySQL includes */
#include "./debug_sync.h"
#include "./my_bit.h"
#include "./my_stacktrace.h"
#include "./sql_audit.h"
#include "./sql_table.h"
#include <mysql/psi/mysql_table.h>
#include <mysql/thread_pool_priv.h>
#include <mysys_err.h>

/* RocksDB includes */
#include "rocksdb/compaction_filter.h"
#include "rocksdb/persistent_cache.h"
#include "rocksdb/rate_limiter.h"
#include "rocksdb/slice_transform.h"
#include "rocksdb/utilities/checkpoint.h"
#include "rocksdb/utilities/convenience.h"
#include "rocksdb/utilities/memory_util.h"

/* MyRocks includes */
#include "./event_listener.h"
#include "./ha_rocksdb_proto.h"
#include "./logger.h"
#include "./rdb_cf_manager.h"
#include "./rdb_cf_options.h"
#include "./rdb_datadic.h"
#include "./rdb_i_s.h"
#include "./rdb_index_merge.h"
#include "./rdb_mutex_wrapper.h"
#include "./rdb_threads.h"

// Internal MySQL APIs not exposed in any header.
extern "C" {
/**
  Mark transaction to rollback and mark error as fatal to a sub-statement.
  @param  thd   Thread handle
  @param  all   TRUE <=> rollback main transaction.
*/
void thd_mark_transaction_to_rollback(MYSQL_THD thd, bool all);

/**
 *   Get the user thread's binary logging format
 *   @param thd  user thread
 *   @return Value to be used as index into the binlog_format_names array
*/
int thd_binlog_format(const MYSQL_THD thd);

/**
 *   Check if binary logging is filtered for thread's current db.
 *   @param  thd   Thread handle
 *   @retval 1 the query is not filtered, 0 otherwise.
*/
bool thd_binlog_filter_ok(const MYSQL_THD thd);
}

namespace myrocks {

static st_global_stats global_stats;
static st_export_stats export_stats;

/**
  Updates row counters based on the table type and operation type.
*/
void ha_rocksdb::update_row_stats(const operation_type &type) {
  DBUG_ASSERT(type < ROWS_MAX);
  // Find if we are modifying system databases.
  if (table->s && m_tbl_def->m_is_mysql_system_table)
    global_stats.system_rows[type].inc();
  else
    global_stats.rows[type].inc();
}

void dbug_dump_database(rocksdb::DB *db);
static handler *rocksdb_create_handler(my_core::handlerton *hton,
                                       my_core::TABLE_SHARE *table_arg,
                                       my_core::MEM_ROOT *mem_root);

bool can_use_bloom_filter(THD *thd, const Rdb_key_def &kd,
                          const rocksdb::Slice &eq_cond,
                          const bool use_all_keys, bool is_ascending);

///////////////////////////////////////////////////////////
// Parameters and settings
///////////////////////////////////////////////////////////
static char *rocksdb_default_cf_options;
static char *rocksdb_override_cf_options;
Rdb_cf_options rocksdb_cf_options_map;

///////////////////////////////////////////////////////////
// Globals
///////////////////////////////////////////////////////////
handlerton *rocksdb_hton;

rocksdb::TransactionDB *rdb = nullptr;

static std::shared_ptr<rocksdb::Statistics> rocksdb_stats;
static std::shared_ptr<Rdb_tbl_prop_coll_factory> properties_collector_factory;

Rdb_dict_manager dict_manager;
Rdb_cf_manager cf_manager;
Rdb_ddl_manager ddl_manager;

/**
  MyRocks background thread control
  N.B. This is besides RocksDB's own background threads
       (@see rocksdb::CancelAllBackgroundWork())
*/

static Rdb_background_thread rdb_bg_thread;

// List of table names (using regex) that are exceptions to the strict
// collation check requirement.
Regex *rdb_collation_exceptions;

static const char *const ERRSTR_ROLLBACK_ONLY =
    "This transaction was rolled back and cannot be "
    "committed. Only supported operation is to roll it back, "
    "so all pending changes will be discarded. "
    "Please restart another transaction.";

static void rocksdb_flush_all_memtables() {
  const Rdb_cf_manager &cf_manager = rdb_get_cf_manager();
  for (const auto &cf_handle : cf_manager.get_all_cf()) {
    rdb->Flush(rocksdb::FlushOptions(), cf_handle);
  }
}

static void rocksdb_compact_column_family_stub(
    THD *const thd, struct st_mysql_sys_var *const var, void *const var_ptr,
    const void *const save) {}

static int rocksdb_compact_column_family(THD *const thd,
                                         struct st_mysql_sys_var *const var,
                                         void *const var_ptr,
                                         struct st_mysql_value *const value) {
  char buff[STRING_BUFFER_USUAL_SIZE];
  int len = sizeof(buff);

  DBUG_ASSERT(value != nullptr);

  if (const char *const cf = value->val_str(value, buff, &len)) {
    bool is_automatic;
    auto cfh = cf_manager.get_cf(cf, "", nullptr, &is_automatic);
    if (cfh != nullptr && rdb != nullptr) {
      sql_print_information("RocksDB: Manual compaction of column family: %s\n",
                            cf);
      rdb->CompactRange(rocksdb::CompactRangeOptions(), cfh, nullptr, nullptr);
    }
  }
  return HA_EXIT_SUCCESS;
}

///////////////////////////////////////////////////////////
// Hash map: table name => open table handler
///////////////////////////////////////////////////////////

namespace // anonymous namespace = not visible outside this source file
{

const ulong TABLE_HASH_SIZE = 32;

struct Rdb_open_tables_map {
  /* Hash table used to track the handlers of open tables */
  my_core::HASH m_hash;
  /* The mutex used to protect the hash table */
  mutable mysql_mutex_t m_mutex;

  void init_hash(void) {
    (void)my_hash_init(&m_hash, my_core::system_charset_info, TABLE_HASH_SIZE,
                       0, 0, (my_hash_get_key)Rdb_open_tables_map::get_hash_key,
                       0, 0);
  }

  void free_hash(void) { my_hash_free(&m_hash); }

  static uchar *get_hash_key(Rdb_table_handler *const table_handler,
                             size_t *const length,
                             my_bool not_used __attribute__((__unused__)));

  Rdb_table_handler *get_table_handler(const char *const table_name);
  void release_table_handler(Rdb_table_handler *const table_handler);

  std::vector<std::string> get_table_names(void) const;
};

} // anonymous namespace

static Rdb_open_tables_map rdb_open_tables;

static std::string rdb_normalize_dir(std::string dir) {
  while (dir.size() > 0 && dir.back() == '/') {
    dir.resize(dir.size() - 1);
  }
  return dir;
}

static int rocksdb_create_checkpoint(THD *const thd __attribute__((__unused__)),
                                     struct st_mysql_sys_var *const var
                                     __attribute__((__unused__)),
                                     void *const save
                                     __attribute__((__unused__)),
                                     struct st_mysql_value *const value) {
  char buf[FN_REFLEN];
  int len = sizeof(buf);
  const char *const checkpoint_dir_raw = value->val_str(value, buf, &len);
  if (checkpoint_dir_raw) {
    if (rdb != nullptr) {
      std::string checkpoint_dir = rdb_normalize_dir(checkpoint_dir_raw);
      // NO_LINT_DEBUG
      sql_print_information("RocksDB: creating checkpoint in directory : %s\n",
                            checkpoint_dir.c_str());
      rocksdb::Checkpoint *checkpoint;
      auto status = rocksdb::Checkpoint::Create(rdb, &checkpoint);
      if (status.ok()) {
        status = checkpoint->CreateCheckpoint(checkpoint_dir.c_str());
        if (status.ok()) {
          sql_print_information(
              "RocksDB: created checkpoint in directory : %s\n",
              checkpoint_dir.c_str());
        } else {
          my_printf_error(
              ER_UNKNOWN_ERROR,
              "RocksDB: Failed to create checkpoint directory. status %d %s",
              MYF(0), status.code(), status.ToString().c_str());
        }
        delete checkpoint;
      } else {
        const std::string err_text(status.ToString());
        my_printf_error(
            ER_UNKNOWN_ERROR,
            "RocksDB: failed to initialize checkpoint. status %d %s\n", MYF(0),
            status.code(), err_text.c_str());
      }
      return status.code();
    }
  }
  return HA_ERR_INTERNAL_ERROR;
}

/* This method is needed to indicate that the
   ROCKSDB_CREATE_CHECKPOINT command is not read-only */
static void rocksdb_create_checkpoint_stub(THD *const thd,
                                           struct st_mysql_sys_var *const var,
                                           void *const var_ptr,
                                           const void *const save) {}

static void rocksdb_force_flush_memtable_now_stub(
    THD *const thd, struct st_mysql_sys_var *const var, void *const var_ptr,
    const void *const save) {}

static int rocksdb_force_flush_memtable_now(
    THD *const thd, struct st_mysql_sys_var *const var, void *const var_ptr,
    struct st_mysql_value *const value) {
  sql_print_information("RocksDB: Manual memtable flush\n");
  rocksdb_flush_all_memtables();
  return HA_EXIT_SUCCESS;
}

static void rocksdb_drop_index_wakeup_thread(
    my_core::THD *const thd __attribute__((__unused__)),
    struct st_mysql_sys_var *const var __attribute__((__unused__)),
    void *const var_ptr __attribute__((__unused__)), const void *const save);

static my_bool rocksdb_pause_background_work = 0;
static mysql_mutex_t rdb_sysvars_mutex;

static void rocksdb_set_pause_background_work(
    my_core::THD *const thd __attribute__((__unused__)),
    struct st_mysql_sys_var *const var __attribute__((__unused__)),
    void *const var_ptr __attribute__((__unused__)), const void *const save) {
  mysql_mutex_lock(&rdb_sysvars_mutex);
  const bool pause_requested = *static_cast<const bool *>(save);
  if (rocksdb_pause_background_work != pause_requested) {
    if (pause_requested) {
      rdb->PauseBackgroundWork();
    } else {
      rdb->ContinueBackgroundWork();
    }
    rocksdb_pause_background_work = pause_requested;
  }
  mysql_mutex_unlock(&rdb_sysvars_mutex);
}

static void rocksdb_set_compaction_options(THD *thd,
                                           struct st_mysql_sys_var *var,
                                           void *var_ptr, const void *save);

static void rocksdb_set_table_stats_sampling_pct(THD *thd,
                                                 struct st_mysql_sys_var *var,
                                                 void *var_ptr,
                                                 const void *save);

static void rocksdb_set_rate_limiter_bytes_per_sec(THD *thd,
                                                   struct st_mysql_sys_var *var,
                                                   void *var_ptr,
                                                   const void *save);

static void rdb_set_collation_exception_list(const char *exception_list);
static void rocksdb_set_collation_exception_list(THD *thd,
                                                 struct st_mysql_sys_var *var,
                                                 void *var_ptr,
                                                 const void *save);

static void rocksdb_set_bulk_load(THD *thd, struct st_mysql_sys_var *var
                                  __attribute__((__unused__)),
                                  void *var_ptr, const void *save);

static void rocksdb_set_max_background_compactions(
    THD *thd, struct st_mysql_sys_var *const var, void *const var_ptr,
    const void *const save);
//////////////////////////////////////////////////////////////////////////////
// Options definitions
//////////////////////////////////////////////////////////////////////////////
static long long rocksdb_block_cache_size;
/* Use unsigned long long instead of uint64_t because of MySQL compatibility */
static unsigned long long // NOLINT(runtime/int)
    rocksdb_rate_limiter_bytes_per_sec;
static unsigned long // NOLINT(runtime/int)
    rocksdb_persistent_cache_size;
static uint64_t rocksdb_info_log_level;
static char *rocksdb_wal_dir;
static char *rocksdb_persistent_cache_path;
static uint64_t rocksdb_index_type;
static char rocksdb_background_sync;
static uint32_t rocksdb_debug_optimizer_n_rows;
static my_bool rocksdb_debug_optimizer_no_zero_cardinality;
static uint32_t rocksdb_wal_recovery_mode;
static uint32_t rocksdb_access_hint_on_compaction_start;
static char *rocksdb_compact_cf_name;
static char *rocksdb_checkpoint_name;
static my_bool rocksdb_signal_drop_index_thread;
static my_bool rocksdb_strict_collation_check = 1;
static my_bool rocksdb_enable_2pc = 0;
static char *rocksdb_strict_collation_exceptions;
static my_bool rocksdb_collect_sst_properties = 1;
static my_bool rocksdb_force_flush_memtable_now_var = 0;
static uint64_t rocksdb_number_stat_computes = 0;
static uint32_t rocksdb_seconds_between_stat_computes = 3600;
static long long rocksdb_compaction_sequential_deletes = 0l;
static long long rocksdb_compaction_sequential_deletes_window = 0l;
static long long rocksdb_compaction_sequential_deletes_file_size = 0l;
static uint32_t rocksdb_validate_tables = 1;
static char *rocksdb_datadir;
static uint32_t rocksdb_table_stats_sampling_pct;
static my_bool rocksdb_enable_bulk_load_api = 1;
static my_bool rpl_skip_tx_api_var = 0;
static my_bool rocksdb_print_snapshot_conflict_queries = 0;

std::atomic<uint64_t> rocksdb_snapshot_conflict_errors(0);
std::atomic<uint64_t> rocksdb_wal_group_syncs(0);

static rocksdb::DBOptions rdb_init_rocksdb_db_options(void) {
  rocksdb::DBOptions o;

  o.create_if_missing = true;
  o.listeners.push_back(std::make_shared<Rdb_event_listener>(&ddl_manager));
  o.info_log_level = rocksdb::InfoLogLevel::INFO_LEVEL;
  o.max_subcompactions = DEFAULT_SUBCOMPACTIONS;

  return o;
}

static rocksdb::DBOptions rocksdb_db_options = rdb_init_rocksdb_db_options();
static rocksdb::BlockBasedTableOptions rocksdb_tbl_options;

static std::shared_ptr<rocksdb::RateLimiter> rocksdb_rate_limiter;

/* This enum needs to be kept up to date with rocksdb::InfoLogLevel */
static const char *info_log_level_names[] = {"debug_level", "info_level",
                                             "warn_level",  "error_level",
                                             "fatal_level", NullS};

static TYPELIB info_log_level_typelib = {
    array_elements(info_log_level_names) - 1, "info_log_level_typelib",
    info_log_level_names, nullptr};

static void rocksdb_set_rocksdb_info_log_level(
    THD *const thd, struct st_mysql_sys_var *const var, void *const var_ptr,
    const void *const save) {
  DBUG_ASSERT(save != nullptr);

  mysql_mutex_lock(&rdb_sysvars_mutex);
  rocksdb_info_log_level = *static_cast<const uint64_t *>(save);
  rocksdb_db_options.info_log->SetInfoLogLevel(
      static_cast<const rocksdb::InfoLogLevel>(rocksdb_info_log_level));
  mysql_mutex_unlock(&rdb_sysvars_mutex);
}

static const char *index_type_names[] = {"kBinarySearch", "kHashSearch", NullS};

static TYPELIB index_type_typelib = {array_elements(index_type_names) - 1,
                                     "index_type_typelib", index_type_names,
                                     nullptr};

const ulong RDB_MAX_LOCK_WAIT_SECONDS = 1024 * 1024 * 1024;
const ulong RDB_MAX_ROW_LOCKS = 1024 * 1024 * 1024;
const ulong RDB_DEFAULT_BULK_LOAD_SIZE = 1000;
const ulong RDB_MAX_BULK_LOAD_SIZE = 1024 * 1024 * 1024;
const size_t RDB_DEFAULT_MERGE_BUF_SIZE = 64 * 1024 * 1024;
const size_t RDB_MIN_MERGE_BUF_SIZE = 100;
const size_t RDB_DEFAULT_MERGE_COMBINE_READ_SIZE = 1024 * 1024 * 1024;
const size_t RDB_MIN_MERGE_COMBINE_READ_SIZE = 100;
const int64 RDB_DEFAULT_BLOCK_CACHE_SIZE = 512 * 1024 * 1024;
const int64 RDB_MIN_BLOCK_CACHE_SIZE = 1024;
const int RDB_MAX_CHECKSUMS_PCT = 100;

// TODO: 0 means don't wait at all, and we don't support it yet?
static MYSQL_THDVAR_ULONG(lock_wait_timeout, PLUGIN_VAR_RQCMDARG,
                          "Number of seconds to wait for lock", nullptr,
                          nullptr, /*default*/ 1, /*min*/ 1,
                          /*max*/ RDB_MAX_LOCK_WAIT_SECONDS, 0);

static MYSQL_THDVAR_BOOL(deadlock_detect, PLUGIN_VAR_RQCMDARG,
                         "Enables deadlock detection", nullptr, nullptr, FALSE);

static MYSQL_THDVAR_BOOL(
    trace_sst_api, PLUGIN_VAR_RQCMDARG,
    "Generate trace output in the log for each call to the SstFileWriter",
    nullptr, nullptr, FALSE);

static MYSQL_THDVAR_BOOL(
    bulk_load, PLUGIN_VAR_RQCMDARG,
    "Use bulk-load mode for inserts. This disables "
    "unique_checks and enables rocksdb_commit_in_the_middle.",
    nullptr, rocksdb_set_bulk_load, FALSE);

static MYSQL_SYSVAR_BOOL(enable_bulk_load_api, rocksdb_enable_bulk_load_api,
                         PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                         "Enables using SstFileWriter for bulk loading",
                         nullptr, nullptr, rocksdb_enable_bulk_load_api);

static MYSQL_THDVAR_STR(tmpdir, PLUGIN_VAR_OPCMDARG | PLUGIN_VAR_MEMALLOC,
                        "Directory for temporary files during DDL operations.",
                        nullptr, nullptr, "");

static MYSQL_THDVAR_BOOL(
    commit_in_the_middle, PLUGIN_VAR_RQCMDARG,
    "Commit rows implicitly every rocksdb_bulk_load_size, on bulk load/insert, "
    "update and delete",
    nullptr, nullptr, FALSE);

static MYSQL_THDVAR_STR(
    read_free_rpl_tables, PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_MEMALLOC,
    "Regex that describes set of tables that will use read-free replication "
    "on the slave (i.e. not lookup a row during replication)",
    nullptr, nullptr, "");

static MYSQL_SYSVAR_BOOL(
    rpl_skip_tx_api, rpl_skip_tx_api_var, PLUGIN_VAR_RQCMDARG,
    "Use write batches for replication thread instead of tx api", nullptr,
    nullptr, FALSE);

static MYSQL_THDVAR_BOOL(skip_bloom_filter_on_read, PLUGIN_VAR_RQCMDARG,
                         "Skip using bloom filter for reads", nullptr, nullptr,
                         FALSE);

static MYSQL_THDVAR_ULONG(max_row_locks, PLUGIN_VAR_RQCMDARG,
                          "Maximum number of locks a transaction can have",
                          nullptr, nullptr,
                          /*default*/ RDB_MAX_ROW_LOCKS,
                          /*min*/ 1,
                          /*max*/ RDB_MAX_ROW_LOCKS, 0);

static MYSQL_THDVAR_BOOL(
    lock_scanned_rows, PLUGIN_VAR_RQCMDARG,
    "Take and hold locks on rows that are scanned but not updated", nullptr,
    nullptr, FALSE);

static MYSQL_THDVAR_ULONG(bulk_load_size, PLUGIN_VAR_RQCMDARG,
                          "Max #records in a batch for bulk-load mode", nullptr,
                          nullptr,
                          /*default*/ RDB_DEFAULT_BULK_LOAD_SIZE,
                          /*min*/ 1,
                          /*max*/ RDB_MAX_BULK_LOAD_SIZE, 0);

static MYSQL_THDVAR_ULONGLONG(
    merge_buf_size, PLUGIN_VAR_RQCMDARG,
    "Size to allocate for merge sort buffers written out to disk "
    "during inplace index creation.",
    nullptr, nullptr,
    /* default (64MB) */ RDB_DEFAULT_MERGE_BUF_SIZE,
    /* min (100B) */ RDB_MIN_MERGE_BUF_SIZE,
    /* max */ SIZE_T_MAX, 1);

static MYSQL_THDVAR_ULONGLONG(
    merge_combine_read_size, PLUGIN_VAR_RQCMDARG,
    "Size that we have to work with during combine (reading from disk) phase "
    "of "
    "external sort during fast index creation.",
    nullptr, nullptr,
    /* default (1GB) */ RDB_DEFAULT_MERGE_COMBINE_READ_SIZE,
    /* min (100B) */ RDB_MIN_MERGE_COMBINE_READ_SIZE,
    /* max */ SIZE_T_MAX, 1);

static MYSQL_SYSVAR_BOOL(
    create_if_missing,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.create_if_missing),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::create_if_missing for RocksDB", nullptr, nullptr,
    rocksdb_db_options.create_if_missing);

static MYSQL_SYSVAR_BOOL(
    create_missing_column_families,
    *reinterpret_cast<my_bool *>(
        &rocksdb_db_options.create_missing_column_families),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::create_missing_column_families for RocksDB", nullptr, nullptr,
    rocksdb_db_options.create_missing_column_families);

static MYSQL_SYSVAR_BOOL(
    error_if_exists,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.error_if_exists),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::error_if_exists for RocksDB", nullptr, nullptr,
    rocksdb_db_options.error_if_exists);

static MYSQL_SYSVAR_BOOL(
    paranoid_checks,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.paranoid_checks),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::paranoid_checks for RocksDB", nullptr, nullptr,
    rocksdb_db_options.paranoid_checks);

static MYSQL_SYSVAR_ULONGLONG(
    rate_limiter_bytes_per_sec, rocksdb_rate_limiter_bytes_per_sec,
    PLUGIN_VAR_RQCMDARG, "DBOptions::rate_limiter bytes_per_sec for RocksDB",
    nullptr, rocksdb_set_rate_limiter_bytes_per_sec, /* default */ 0L,
    /* min */ 0L, /* max */ MAX_RATE_LIMITER_BYTES_PER_SEC, 0);

static MYSQL_SYSVAR_ENUM(
    info_log_level, rocksdb_info_log_level, PLUGIN_VAR_RQCMDARG,
    "Filter level for info logs to be written mysqld error log. "
    "Valid values include 'debug_level', 'info_level', 'warn_level'"
    "'error_level' and 'fatal_level'.",
    nullptr, rocksdb_set_rocksdb_info_log_level,
    rocksdb::InfoLogLevel::ERROR_LEVEL, &info_log_level_typelib);

static MYSQL_THDVAR_INT(
    perf_context_level, PLUGIN_VAR_RQCMDARG,
    "Perf Context Level for rocksdb internal timer stat collection", nullptr,
    nullptr,
    /* default */ rocksdb::PerfLevel::kUninitialized,
    /* min */ rocksdb::PerfLevel::kUninitialized,
    /* max */ rocksdb::PerfLevel::kOutOfBounds - 1, 0);

static MYSQL_SYSVAR_UINT(
    wal_recovery_mode, rocksdb_wal_recovery_mode, PLUGIN_VAR_RQCMDARG,
    "DBOptions::wal_recovery_mode for RocksDB", nullptr, nullptr,
    /* default */ (uint)rocksdb::WALRecoveryMode::kPointInTimeRecovery,
    /* min */ (uint)rocksdb::WALRecoveryMode::kTolerateCorruptedTailRecords,
    /* max */ (uint)rocksdb::WALRecoveryMode::kSkipAnyCorruptedRecords, 0);

static MYSQL_SYSVAR_ULONG(compaction_readahead_size,
                          rocksdb_db_options.compaction_readahead_size,
                          PLUGIN_VAR_RQCMDARG,
                          "DBOptions::compaction_readahead_size for RocksDB",
                          nullptr, nullptr,
                          rocksdb_db_options.compaction_readahead_size,
                          /* min */ 0L, /* max */ ULONG_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    new_table_reader_for_compaction_inputs,
    *reinterpret_cast<my_bool *>(
        &rocksdb_db_options.new_table_reader_for_compaction_inputs),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::new_table_reader_for_compaction_inputs for RocksDB", nullptr,
    nullptr, rocksdb_db_options.new_table_reader_for_compaction_inputs);

static MYSQL_SYSVAR_UINT(
    access_hint_on_compaction_start, rocksdb_access_hint_on_compaction_start,
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::access_hint_on_compaction_start for RocksDB", nullptr, nullptr,
    /* default */ (uint)rocksdb::Options::AccessHint::NORMAL,
    /* min */ (uint)rocksdb::Options::AccessHint::NONE,
    /* max */ (uint)rocksdb::Options::AccessHint::WILLNEED, 0);

static MYSQL_SYSVAR_BOOL(
    allow_concurrent_memtable_write,
    *reinterpret_cast<my_bool *>(
        &rocksdb_db_options.allow_concurrent_memtable_write),
    PLUGIN_VAR_RQCMDARG,
    "DBOptions::allow_concurrent_memtable_write for RocksDB", nullptr, nullptr,
    false);

static MYSQL_SYSVAR_BOOL(
    enable_write_thread_adaptive_yield,
    *reinterpret_cast<my_bool *>(
        &rocksdb_db_options.enable_write_thread_adaptive_yield),
    PLUGIN_VAR_RQCMDARG,
    "DBOptions::enable_write_thread_adaptive_yield for RocksDB", nullptr,
    nullptr, false);

static MYSQL_SYSVAR_INT(max_open_files, rocksdb_db_options.max_open_files,
                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                        "DBOptions::max_open_files for RocksDB", nullptr,
                        nullptr, rocksdb_db_options.max_open_files,
                        /* min */ -1, /* max */ INT_MAX, 0);

static MYSQL_SYSVAR_ULONG(max_total_wal_size,
                          rocksdb_db_options.max_total_wal_size,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::max_total_wal_size for RocksDB", nullptr,
                          nullptr, rocksdb_db_options.max_total_wal_size,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    disabledatasync,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.disableDataSync),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::disableDataSync for RocksDB", nullptr, nullptr,
    rocksdb_db_options.disableDataSync);

static MYSQL_SYSVAR_BOOL(
    use_fsync, *reinterpret_cast<my_bool *>(&rocksdb_db_options.use_fsync),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::use_fsync for RocksDB", nullptr, nullptr,
    rocksdb_db_options.use_fsync);

static MYSQL_SYSVAR_STR(wal_dir, rocksdb_wal_dir,
                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                        "DBOptions::wal_dir for RocksDB", nullptr, nullptr,
                        rocksdb_db_options.wal_dir.c_str());

static MYSQL_SYSVAR_STR(
    persistent_cache_path, rocksdb_persistent_cache_path,
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "Path for BlockBasedTableOptions::persistent_cache for RocksDB", nullptr,
    nullptr, "");

static MYSQL_SYSVAR_ULONG(
    persistent_cache_size, rocksdb_persistent_cache_size,
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "Size of cache for BlockBasedTableOptions::persistent_cache for RocksDB",
    nullptr, nullptr, rocksdb_persistent_cache_size,
    /* min */ 0L, /* max */ ULONG_MAX, 0);

static MYSQL_SYSVAR_ULONG(
    delete_obsolete_files_period_micros,
    rocksdb_db_options.delete_obsolete_files_period_micros,
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::delete_obsolete_files_period_micros for RocksDB", nullptr,
    nullptr, rocksdb_db_options.delete_obsolete_files_period_micros,
    /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_INT(base_background_compactions,
                        rocksdb_db_options.base_background_compactions,
                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                        "DBOptions::base_background_compactions for RocksDB",
                        nullptr, nullptr,
                        rocksdb_db_options.base_background_compactions,
                        /* min */ -1, /* max */ MAX_BACKGROUND_COMPACTIONS, 0);

static MYSQL_SYSVAR_INT(max_background_compactions,
                        rocksdb_db_options.max_background_compactions,
                        PLUGIN_VAR_RQCMDARG,
                        "DBOptions::max_background_compactions for RocksDB",
                        nullptr, rocksdb_set_max_background_compactions,
                        rocksdb_db_options.max_background_compactions,
                        /* min */ 1, /* max */ MAX_BACKGROUND_COMPACTIONS, 0);

static MYSQL_SYSVAR_INT(max_background_flushes,
                        rocksdb_db_options.max_background_flushes,
                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                        "DBOptions::max_background_flushes for RocksDB",
                        nullptr, nullptr,
                        rocksdb_db_options.max_background_flushes,
                        /* min */ 1, /* max */ MAX_BACKGROUND_FLUSHES, 0);

static MYSQL_SYSVAR_UINT(max_subcompactions,
                         rocksdb_db_options.max_subcompactions,
                         PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                         "DBOptions::max_subcompactions for RocksDB", nullptr,
                         nullptr, rocksdb_db_options.max_subcompactions,
                         /* min */ 1, /* max */ MAX_SUBCOMPACTIONS, 0);

static MYSQL_SYSVAR_ULONG(max_log_file_size,
                          rocksdb_db_options.max_log_file_size,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::max_log_file_size for RocksDB", nullptr,
                          nullptr, rocksdb_db_options.max_log_file_size,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_ULONG(log_file_time_to_roll,
                          rocksdb_db_options.log_file_time_to_roll,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::log_file_time_to_roll for RocksDB",
                          nullptr, nullptr,
                          rocksdb_db_options.log_file_time_to_roll,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_ULONG(keep_log_file_num,
                          rocksdb_db_options.keep_log_file_num,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::keep_log_file_num for RocksDB", nullptr,
                          nullptr, rocksdb_db_options.keep_log_file_num,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_ULONG(max_manifest_file_size,
                          rocksdb_db_options.max_manifest_file_size,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::max_manifest_file_size for RocksDB",
                          nullptr, nullptr,
                          rocksdb_db_options.max_manifest_file_size,
                          /* min */ 0L, /* max */ ULONG_MAX, 0);

static MYSQL_SYSVAR_INT(table_cache_numshardbits,
                        rocksdb_db_options.table_cache_numshardbits,
                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                        "DBOptions::table_cache_numshardbits for RocksDB",
                        nullptr, nullptr,
                        rocksdb_db_options.table_cache_numshardbits,
                        /* min */ 0, /* max */ INT_MAX, 0);

static MYSQL_SYSVAR_ULONG(wal_ttl_seconds, rocksdb_db_options.WAL_ttl_seconds,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::WAL_ttl_seconds for RocksDB", nullptr,
                          nullptr, rocksdb_db_options.WAL_ttl_seconds,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_ULONG(wal_size_limit_mb,
                          rocksdb_db_options.WAL_size_limit_MB,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::WAL_size_limit_MB for RocksDB", nullptr,
                          nullptr, rocksdb_db_options.WAL_size_limit_MB,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_ULONG(manifest_preallocation_size,
                          rocksdb_db_options.manifest_preallocation_size,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::manifest_preallocation_size for RocksDB",
                          nullptr, nullptr,
                          rocksdb_db_options.manifest_preallocation_size,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    use_direct_reads,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.use_direct_reads),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::use_direct_reads for RocksDB", nullptr, nullptr,
    rocksdb_db_options.use_direct_reads);

static MYSQL_SYSVAR_BOOL(
    use_direct_writes,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.use_direct_writes),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::use_direct_writes for RocksDB", nullptr, nullptr,
    rocksdb_db_options.use_direct_writes);

static MYSQL_SYSVAR_BOOL(
    allow_mmap_reads,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.allow_mmap_reads),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::allow_mmap_reads for RocksDB", nullptr, nullptr,
    rocksdb_db_options.allow_mmap_reads);

static MYSQL_SYSVAR_BOOL(
    allow_mmap_writes,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.allow_mmap_writes),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::allow_mmap_writes for RocksDB", nullptr, nullptr,
    rocksdb_db_options.allow_mmap_writes);

static MYSQL_SYSVAR_BOOL(
    is_fd_close_on_exec,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.is_fd_close_on_exec),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::is_fd_close_on_exec for RocksDB", nullptr, nullptr,
    rocksdb_db_options.is_fd_close_on_exec);

static MYSQL_SYSVAR_UINT(stats_dump_period_sec,
                         rocksdb_db_options.stats_dump_period_sec,
                         PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                         "DBOptions::stats_dump_period_sec for RocksDB",
                         nullptr, nullptr,
                         rocksdb_db_options.stats_dump_period_sec,
                         /* min */ 0, /* max */ INT_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    advise_random_on_open,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.advise_random_on_open),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::advise_random_on_open for RocksDB", nullptr, nullptr,
    rocksdb_db_options.advise_random_on_open);

static MYSQL_SYSVAR_ULONG(db_write_buffer_size,
                          rocksdb_db_options.db_write_buffer_size,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::db_write_buffer_size for RocksDB",
                          nullptr, nullptr,
                          rocksdb_db_options.db_write_buffer_size,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    use_adaptive_mutex,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.use_adaptive_mutex),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::use_adaptive_mutex for RocksDB", nullptr, nullptr,
    rocksdb_db_options.use_adaptive_mutex);

static MYSQL_SYSVAR_ULONG(bytes_per_sync, rocksdb_db_options.bytes_per_sync,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::bytes_per_sync for RocksDB", nullptr,
                          nullptr, rocksdb_db_options.bytes_per_sync,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_ULONG(wal_bytes_per_sync,
                          rocksdb_db_options.wal_bytes_per_sync,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "DBOptions::wal_bytes_per_sync for RocksDB", nullptr,
                          nullptr, rocksdb_db_options.wal_bytes_per_sync,
                          /* min */ 0L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    enable_thread_tracking,
    *reinterpret_cast<my_bool *>(&rocksdb_db_options.enable_thread_tracking),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "DBOptions::enable_thread_tracking for RocksDB", nullptr, nullptr,
    rocksdb_db_options.enable_thread_tracking);

static MYSQL_SYSVAR_LONGLONG(block_cache_size, rocksdb_block_cache_size,
                             PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                             "block_cache size for RocksDB", nullptr, nullptr,
                             /* default */ RDB_DEFAULT_BLOCK_CACHE_SIZE,
                             /* min */ RDB_MIN_BLOCK_CACHE_SIZE,
                             /* max */ LONGLONG_MAX,
                             /* Block size */ RDB_MIN_BLOCK_CACHE_SIZE);

static MYSQL_SYSVAR_BOOL(
    cache_index_and_filter_blocks,
    *reinterpret_cast<my_bool *>(
        &rocksdb_tbl_options.cache_index_and_filter_blocks),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "BlockBasedTableOptions::cache_index_and_filter_blocks for RocksDB",
    nullptr, nullptr, true);

// When pin_l0_filter_and_index_blocks_in_cache is true, RocksDB will  use the
// LRU cache, but will always keep the filter & idndex block's handle checked
// out (=won't call ShardedLRUCache::Release), plus the parsed out objects
// the LRU cache will never push flush them out, hence they're pinned.
//
// This fixes the mutex contention between :ShardedLRUCache::Lookup and
// ShardedLRUCache::Release which reduced the QPS ratio (QPS using secondary
// index / QPS using PK).
static MYSQL_SYSVAR_BOOL(
    pin_l0_filter_and_index_blocks_in_cache,
    *reinterpret_cast<my_bool *>(
        &rocksdb_tbl_options.pin_l0_filter_and_index_blocks_in_cache),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "pin_l0_filter_and_index_blocks_in_cache for RocksDB", nullptr, nullptr,
    true);

static MYSQL_SYSVAR_ENUM(index_type, rocksdb_index_type,
                         PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                         "BlockBasedTableOptions::index_type for RocksDB",
                         nullptr, nullptr,
                         (uint64_t)rocksdb_tbl_options.index_type,
                         &index_type_typelib);

static MYSQL_SYSVAR_BOOL(
    hash_index_allow_collision,
    *reinterpret_cast<my_bool *>(
        &rocksdb_tbl_options.hash_index_allow_collision),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "BlockBasedTableOptions::hash_index_allow_collision for RocksDB", nullptr,
    nullptr, rocksdb_tbl_options.hash_index_allow_collision);

static MYSQL_SYSVAR_BOOL(
    no_block_cache,
    *reinterpret_cast<my_bool *>(&rocksdb_tbl_options.no_block_cache),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "BlockBasedTableOptions::no_block_cache for RocksDB", nullptr, nullptr,
    rocksdb_tbl_options.no_block_cache);

static MYSQL_SYSVAR_ULONG(block_size, rocksdb_tbl_options.block_size,
                          PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                          "BlockBasedTableOptions::block_size for RocksDB",
                          nullptr, nullptr, rocksdb_tbl_options.block_size,
                          /* min */ 1L, /* max */ LONG_MAX, 0);

static MYSQL_SYSVAR_INT(
    block_size_deviation, rocksdb_tbl_options.block_size_deviation,
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "BlockBasedTableOptions::block_size_deviation for RocksDB", nullptr,
    nullptr, rocksdb_tbl_options.block_size_deviation,
    /* min */ 0, /* max */ INT_MAX, 0);

static MYSQL_SYSVAR_INT(
    block_restart_interval, rocksdb_tbl_options.block_restart_interval,
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "BlockBasedTableOptions::block_restart_interval for RocksDB", nullptr,
    nullptr, rocksdb_tbl_options.block_restart_interval,
    /* min */ 1, /* max */ INT_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    whole_key_filtering,
    *reinterpret_cast<my_bool *>(&rocksdb_tbl_options.whole_key_filtering),
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "BlockBasedTableOptions::whole_key_filtering for RocksDB", nullptr, nullptr,
    rocksdb_tbl_options.whole_key_filtering);

static MYSQL_SYSVAR_STR(default_cf_options, rocksdb_default_cf_options,
                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                        "default cf options for RocksDB", nullptr, nullptr, "");

static MYSQL_SYSVAR_STR(override_cf_options, rocksdb_override_cf_options,
                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                        "option overrides per cf for RocksDB", nullptr, nullptr,
                        "");

static MYSQL_SYSVAR_BOOL(background_sync, rocksdb_background_sync,
                         PLUGIN_VAR_RQCMDARG,
                         "turns on background syncs for RocksDB", nullptr,
                         nullptr, FALSE);

static MYSQL_THDVAR_BOOL(write_sync, PLUGIN_VAR_RQCMDARG,
                         "WriteOptions::sync for RocksDB", nullptr, nullptr,
                         rocksdb::WriteOptions().sync);

static MYSQL_THDVAR_BOOL(write_disable_wal, PLUGIN_VAR_RQCMDARG,
                         "WriteOptions::disableWAL for RocksDB", nullptr,
                         nullptr, rocksdb::WriteOptions().disableWAL);

static MYSQL_THDVAR_BOOL(
    write_ignore_missing_column_families, PLUGIN_VAR_RQCMDARG,
    "WriteOptions::ignore_missing_column_families for RocksDB", nullptr,
    nullptr, rocksdb::WriteOptions().ignore_missing_column_families);

static MYSQL_THDVAR_BOOL(skip_fill_cache, PLUGIN_VAR_RQCMDARG,
                         "Skip filling block cache on read requests", nullptr,
                         nullptr, FALSE);

static MYSQL_THDVAR_BOOL(
    unsafe_for_binlog, PLUGIN_VAR_RQCMDARG,
    "Allowing statement based binary logging which may break consistency",
    nullptr, nullptr, FALSE);

static MYSQL_THDVAR_UINT(records_in_range, PLUGIN_VAR_RQCMDARG,
                         "Used to override the result of records_in_range(). "
                         "Set to a positive number to override",
                         nullptr, nullptr, 0,
                         /* min */ 0, /* max */ INT_MAX, 0);

static MYSQL_THDVAR_UINT(force_index_records_in_range, PLUGIN_VAR_RQCMDARG,
                         "Used to override the result of records_in_range() "
                         "when FORCE INDEX is used.",
                         nullptr, nullptr, 0,
                         /* min */ 0, /* max */ INT_MAX, 0);

static MYSQL_SYSVAR_UINT(
    debug_optimizer_n_rows, rocksdb_debug_optimizer_n_rows,
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY | PLUGIN_VAR_NOSYSVAR,
    "Test only to override rocksdb estimates of table size in a memtable",
    nullptr, nullptr, 0, /* min */ 0, /* max */ INT_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    debug_optimizer_no_zero_cardinality,
    rocksdb_debug_optimizer_no_zero_cardinality, PLUGIN_VAR_RQCMDARG,
    "In case if cardinality is zero, overrides it with some value", nullptr,
    nullptr, TRUE);

static MYSQL_SYSVAR_STR(compact_cf, rocksdb_compact_cf_name,
                        PLUGIN_VAR_RQCMDARG, "Compact column family",
                        rocksdb_compact_column_family,
                        rocksdb_compact_column_family_stub, "");

static MYSQL_SYSVAR_STR(create_checkpoint, rocksdb_checkpoint_name,
                        PLUGIN_VAR_RQCMDARG, "Checkpoint directory",
                        rocksdb_create_checkpoint,
                        rocksdb_create_checkpoint_stub, "");

static MYSQL_SYSVAR_BOOL(signal_drop_index_thread,
                         rocksdb_signal_drop_index_thread, PLUGIN_VAR_RQCMDARG,
                         "Wake up drop index thread", nullptr,
                         rocksdb_drop_index_wakeup_thread, FALSE);

static MYSQL_SYSVAR_BOOL(pause_background_work, rocksdb_pause_background_work,
                         PLUGIN_VAR_RQCMDARG,
                         "Disable all rocksdb background operations", nullptr,
                         rocksdb_set_pause_background_work, FALSE);

static MYSQL_SYSVAR_BOOL(enable_2pc, rocksdb_enable_2pc, PLUGIN_VAR_RQCMDARG,
                         "Enable two phase commit for MyRocks", nullptr,
                         nullptr, TRUE);

static MYSQL_SYSVAR_BOOL(strict_collation_check, rocksdb_strict_collation_check,
                         PLUGIN_VAR_RQCMDARG,
                         "Enforce case sensitive collation for MyRocks indexes",
                         nullptr, nullptr, TRUE);

static MYSQL_SYSVAR_STR(strict_collation_exceptions,
                        rocksdb_strict_collation_exceptions,
                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_MEMALLOC,
                        "Regex that describes set of tables that are excluded "
                        "from the case sensitive collation enforcement",
                        nullptr, rocksdb_set_collation_exception_list, "");

static MYSQL_SYSVAR_BOOL(collect_sst_properties, rocksdb_collect_sst_properties,
                         PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
                         "Enables collecting SST file properties on each flush",
                         nullptr, nullptr, rocksdb_collect_sst_properties);

static MYSQL_SYSVAR_BOOL(
    force_flush_memtable_now, rocksdb_force_flush_memtable_now_var,
    PLUGIN_VAR_RQCMDARG,
    "Forces memstore flush which may block all write requests so be careful",
    rocksdb_force_flush_memtable_now, rocksdb_force_flush_memtable_now_stub,
    FALSE);

static MYSQL_THDVAR_BOOL(
    flush_memtable_on_analyze, PLUGIN_VAR_RQCMDARG,
    "Forces memtable flush on ANALZYE table to get accurate cardinality",
    nullptr, nullptr, true);

static MYSQL_SYSVAR_UINT(
    seconds_between_stat_computes, rocksdb_seconds_between_stat_computes,
    PLUGIN_VAR_RQCMDARG,
    "Sets a number of seconds to wait between optimizer stats recomputation. "
    "Only changed indexes will be refreshed.",
    nullptr, nullptr, rocksdb_seconds_between_stat_computes,
    /* min */ 0L, /* max */ UINT_MAX, 0);

static MYSQL_SYSVAR_LONGLONG(compaction_sequential_deletes,
                             rocksdb_compaction_sequential_deletes,
                             PLUGIN_VAR_RQCMDARG,
                             "RocksDB will trigger compaction for the file if "
                             "it has more than this number sequential deletes "
                             "per window",
                             nullptr, rocksdb_set_compaction_options,
                             DEFAULT_COMPACTION_SEQUENTIAL_DELETES,
                             /* min */ 0L,
                             /* max */ MAX_COMPACTION_SEQUENTIAL_DELETES, 0);

static MYSQL_SYSVAR_LONGLONG(
    compaction_sequential_deletes_window,
    rocksdb_compaction_sequential_deletes_window, PLUGIN_VAR_RQCMDARG,
    "Size of the window for counting rocksdb_compaction_sequential_deletes",
    nullptr, rocksdb_set_compaction_options,
    DEFAULT_COMPACTION_SEQUENTIAL_DELETES_WINDOW,
    /* min */ 0L, /* max */ MAX_COMPACTION_SEQUENTIAL_DELETES_WINDOW, 0);

static MYSQL_SYSVAR_LONGLONG(
    compaction_sequential_deletes_file_size,
    rocksdb_compaction_sequential_deletes_file_size, PLUGIN_VAR_RQCMDARG,
    "Minimum file size required for compaction_sequential_deletes", nullptr,
    rocksdb_set_compaction_options, 0L,
    /* min */ -1L, /* max */ LONGLONG_MAX, 0);

static MYSQL_SYSVAR_BOOL(
    compaction_sequential_deletes_count_sd,
    rocksdb_compaction_sequential_deletes_count_sd, PLUGIN_VAR_RQCMDARG,
    "Counting SingleDelete as rocksdb_compaction_sequential_deletes", nullptr,
    nullptr, rocksdb_compaction_sequential_deletes_count_sd);

static MYSQL_SYSVAR_BOOL(
    print_snapshot_conflict_queries, rocksdb_print_snapshot_conflict_queries,
    PLUGIN_VAR_RQCMDARG,
    "Logging queries that got snapshot conflict errors into *.err log", nullptr,
    nullptr, rocksdb_print_snapshot_conflict_queries);

static MYSQL_THDVAR_INT(checksums_pct, PLUGIN_VAR_RQCMDARG,
                        "How many percentages of rows to be checksummed",
                        nullptr, nullptr, RDB_MAX_CHECKSUMS_PCT,
                        /* min */ 0, /* max */ RDB_MAX_CHECKSUMS_PCT, 0);

static MYSQL_THDVAR_BOOL(store_row_debug_checksums, PLUGIN_VAR_RQCMDARG,
                         "Include checksums when writing index/table records",
                         nullptr, nullptr, false /* default value */);

static MYSQL_THDVAR_BOOL(verify_row_debug_checksums, PLUGIN_VAR_RQCMDARG,
                         "Verify checksums when reading index/table records",
                         nullptr, nullptr, false /* default value */);

static MYSQL_SYSVAR_UINT(
    validate_tables, rocksdb_validate_tables,
    PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
    "Verify all .frm files match all RocksDB tables (0 means no verification, "
    "1 means verify and fail on error, and 2 means verify but continue",
    nullptr, nullptr, 1 /* default value */, 0 /* min value */,
    2 /* max value */, 0);

static MYSQL_SYSVAR_STR(datadir, rocksdb_datadir,
                        PLUGIN_VAR_OPCMDARG | PLUGIN_VAR_READONLY,
                        "RocksDB data directory", nullptr, nullptr,
                        "./.rocksdb");

static MYSQL_SYSVAR_UINT(
    table_stats_sampling_pct, rocksdb_table_stats_sampling_pct,
    PLUGIN_VAR_RQCMDARG,
    "Percentage of entries to sample when collecting statistics about table "
    "properties. Specify either 0 to sample everything or percentage "
    "[" STRINGIFY_ARG(RDB_TBL_STATS_SAMPLE_PCT_MIN) ".." STRINGIFY_ARG(
        RDB_TBL_STATS_SAMPLE_PCT_MAX) "]. "
                                      "By default " STRINGIFY_ARG(
                                          RDB_DEFAULT_TBL_STATS_SAMPLE_PCT) "% "
                                                                            "of"
                                                                            " e"
                                                                            "nt"
                                                                            "ri"
                                                                            "es"
                                                                            " a"
                                                                            "re"
                                                                            " "
                                                                            "sa"
                                                                            "mp"
                                                                            "le"
                                                                            "d"
                                                                            ".",
    nullptr, rocksdb_set_table_stats_sampling_pct, /* default */
    RDB_DEFAULT_TBL_STATS_SAMPLE_PCT, /* everything */ 0,
    /* max */ RDB_TBL_STATS_SAMPLE_PCT_MAX, 0);

static const int ROCKSDB_ASSUMED_KEY_VALUE_DISK_SIZE = 100;

static struct st_mysql_sys_var *rocksdb_system_variables[] = {
    MYSQL_SYSVAR(lock_wait_timeout),
    MYSQL_SYSVAR(deadlock_detect),
    MYSQL_SYSVAR(max_row_locks),
    MYSQL_SYSVAR(lock_scanned_rows),
    MYSQL_SYSVAR(bulk_load),
    MYSQL_SYSVAR(trace_sst_api),
    MYSQL_SYSVAR(commit_in_the_middle),
    MYSQL_SYSVAR(read_free_rpl_tables),
    MYSQL_SYSVAR(rpl_skip_tx_api),
    MYSQL_SYSVAR(bulk_load_size),
    MYSQL_SYSVAR(merge_buf_size),
    MYSQL_SYSVAR(enable_bulk_load_api),
    MYSQL_SYSVAR(tmpdir),
    MYSQL_SYSVAR(merge_combine_read_size),
    MYSQL_SYSVAR(skip_bloom_filter_on_read),

    MYSQL_SYSVAR(create_if_missing),
    MYSQL_SYSVAR(create_missing_column_families),
    MYSQL_SYSVAR(error_if_exists),
    MYSQL_SYSVAR(paranoid_checks),
    MYSQL_SYSVAR(rate_limiter_bytes_per_sec),
    MYSQL_SYSVAR(info_log_level),
    MYSQL_SYSVAR(max_open_files),
    MYSQL_SYSVAR(max_total_wal_size),
    MYSQL_SYSVAR(disabledatasync),
    MYSQL_SYSVAR(use_fsync),
    MYSQL_SYSVAR(wal_dir),
    MYSQL_SYSVAR(persistent_cache_path),
    MYSQL_SYSVAR(persistent_cache_size),
    MYSQL_SYSVAR(delete_obsolete_files_period_micros),
    MYSQL_SYSVAR(base_background_compactions),
    MYSQL_SYSVAR(max_background_compactions),
    MYSQL_SYSVAR(max_background_flushes),
    MYSQL_SYSVAR(max_log_file_size),
    MYSQL_SYSVAR(max_subcompactions),
    MYSQL_SYSVAR(log_file_time_to_roll),
    MYSQL_SYSVAR(keep_log_file_num),
    MYSQL_SYSVAR(max_manifest_file_size),
    MYSQL_SYSVAR(table_cache_numshardbits),
    MYSQL_SYSVAR(wal_ttl_seconds),
    MYSQL_SYSVAR(wal_size_limit_mb),
    MYSQL_SYSVAR(manifest_preallocation_size),
    MYSQL_SYSVAR(use_direct_reads),
    MYSQL_SYSVAR(use_direct_writes),
    MYSQL_SYSVAR(allow_mmap_reads),
    MYSQL_SYSVAR(allow_mmap_writes),
    MYSQL_SYSVAR(is_fd_close_on_exec),
    MYSQL_SYSVAR(stats_dump_period_sec),
    MYSQL_SYSVAR(advise_random_on_open),
    MYSQL_SYSVAR(db_write_buffer_size),
    MYSQL_SYSVAR(use_adaptive_mutex),
    MYSQL_SYSVAR(bytes_per_sync),
    MYSQL_SYSVAR(wal_bytes_per_sync),
    MYSQL_SYSVAR(enable_thread_tracking),
    MYSQL_SYSVAR(perf_context_level),
    MYSQL_SYSVAR(wal_recovery_mode),
    MYSQL_SYSVAR(access_hint_on_compaction_start),
    MYSQL_SYSVAR(new_table_reader_for_compaction_inputs),
    MYSQL_SYSVAR(compaction_readahead_size),
    MYSQL_SYSVAR(allow_concurrent_memtable_write),
    MYSQL_SYSVAR(enable_write_thread_adaptive_yield),

    MYSQL_SYSVAR(block_cache_size),
    MYSQL_SYSVAR(cache_index_and_filter_blocks),
    MYSQL_SYSVAR(pin_l0_filter_and_index_blocks_in_cache),
    MYSQL_SYSVAR(index_type),
    MYSQL_SYSVAR(hash_index_allow_collision),
    MYSQL_SYSVAR(no_block_cache),
    MYSQL_SYSVAR(block_size),
    MYSQL_SYSVAR(block_size_deviation),
    MYSQL_SYSVAR(block_restart_interval),
    MYSQL_SYSVAR(whole_key_filtering),

    MYSQL_SYSVAR(default_cf_options),
    MYSQL_SYSVAR(override_cf_options),

    MYSQL_SYSVAR(background_sync),

    MYSQL_SYSVAR(write_sync),
    MYSQL_SYSVAR(write_disable_wal),
    MYSQL_SYSVAR(write_ignore_missing_column_families),

    MYSQL_SYSVAR(skip_fill_cache),
    MYSQL_SYSVAR(unsafe_for_binlog),

    MYSQL_SYSVAR(records_in_range),
    MYSQL_SYSVAR(force_index_records_in_range),
    MYSQL_SYSVAR(debug_optimizer_n_rows),
    MYSQL_SYSVAR(debug_optimizer_no_zero_cardinality),

    MYSQL_SYSVAR(compact_cf),
    MYSQL_SYSVAR(signal_drop_index_thread),
    MYSQL_SYSVAR(pause_background_work),
    MYSQL_SYSVAR(enable_2pc),
    MYSQL_SYSVAR(strict_collation_check),
    MYSQL_SYSVAR(strict_collation_exceptions),
    MYSQL_SYSVAR(collect_sst_properties),
    MYSQL_SYSVAR(force_flush_memtable_now),
    MYSQL_SYSVAR(flush_memtable_on_analyze),
    MYSQL_SYSVAR(seconds_between_stat_computes),

    MYSQL_SYSVAR(compaction_sequential_deletes),
    MYSQL_SYSVAR(compaction_sequential_deletes_window),
    MYSQL_SYSVAR(compaction_sequential_deletes_file_size),
    MYSQL_SYSVAR(compaction_sequential_deletes_count_sd),
    MYSQL_SYSVAR(print_snapshot_conflict_queries),

    MYSQL_SYSVAR(datadir),
    MYSQL_SYSVAR(create_checkpoint),

    MYSQL_SYSVAR(checksums_pct),
    MYSQL_SYSVAR(store_row_debug_checksums),
    MYSQL_SYSVAR(verify_row_debug_checksums),

    MYSQL_SYSVAR(validate_tables),
    MYSQL_SYSVAR(table_stats_sampling_pct),
    nullptr};

static rocksdb::WriteOptions
rdb_get_rocksdb_write_options(my_core::THD *const thd) {
  rocksdb::WriteOptions opt;

  opt.sync = THDVAR(thd, write_sync);
  opt.disableWAL = THDVAR(thd, write_disable_wal);
  opt.ignore_missing_column_families =
      THDVAR(thd, write_ignore_missing_column_families);

  return opt;
}

///////////////////////////////////////////////////////////////////////////////////////////

/**
  @brief
  Function we use in the creation of our hash to get key.
*/

uchar *Rdb_open_tables_map::get_hash_key(Rdb_table_handler *const table_handler,
                                         size_t *const length, my_bool not_used
                                         __attribute__((__unused__))) {
  *length = table_handler->m_table_name_length;
  return reinterpret_cast<uchar *>(table_handler->m_table_name);
}

/*
  The following is needed as an argument for mysql_stage_register,
  irrespectively of whether we're compiling with P_S or not.
*/
PSI_stage_info stage_waiting_on_row_lock = {0, "Waiting for row lock", 0};

#ifdef HAVE_PSI_INTERFACE
static PSI_thread_key rdb_background_psi_thread_key;
static PSI_thread_key rdb_drop_idx_psi_thread_key;

static PSI_stage_info *all_rocksdb_stages[] = {&stage_waiting_on_row_lock};

static my_core::PSI_mutex_key rdb_psi_open_tbls_mutex_key,
    rdb_signal_bg_psi_mutex_key, rdb_signal_drop_idx_psi_mutex_key,
    rdb_collation_data_mutex_key, rdb_mem_cmp_space_mutex_key,
    key_mutex_tx_list, rdb_sysvars_psi_mutex_key;

static PSI_mutex_info all_rocksdb_mutexes[] = {
    {&rdb_psi_open_tbls_mutex_key, "open tables", PSI_FLAG_GLOBAL},
    {&rdb_signal_bg_psi_mutex_key, "stop background", PSI_FLAG_GLOBAL},
    {&rdb_signal_drop_idx_psi_mutex_key, "signal drop index", PSI_FLAG_GLOBAL},
    {&rdb_collation_data_mutex_key, "collation data init", PSI_FLAG_GLOBAL},
    {&rdb_mem_cmp_space_mutex_key, "collation space char data init",
     PSI_FLAG_GLOBAL},
    {&key_mutex_tx_list, "tx_list", PSI_FLAG_GLOBAL},
    {&rdb_sysvars_psi_mutex_key, "setting sysvar", PSI_FLAG_GLOBAL},
};

static PSI_rwlock_key key_rwlock_collation_exception_list;
static PSI_rwlock_key key_rwlock_read_free_rpl_tables;

static PSI_rwlock_info all_rocksdb_rwlocks[] = {
    {&key_rwlock_collation_exception_list, "collation_exception_list",
     PSI_FLAG_GLOBAL},
    {&key_rwlock_read_free_rpl_tables, "read_free_rpl_tables", PSI_FLAG_GLOBAL}
};

PSI_cond_key rdb_signal_bg_psi_cond_key, rdb_signal_drop_idx_psi_cond_key;

static PSI_cond_info all_rocksdb_conds[] = {
    {&rdb_signal_bg_psi_cond_key, "cond signal background", PSI_FLAG_GLOBAL},
    {&rdb_signal_drop_idx_psi_cond_key, "cond signal drop index",
     PSI_FLAG_GLOBAL},
};

static PSI_thread_info all_rocksdb_threads[] = {
    {&rdb_background_psi_thread_key, "background", PSI_FLAG_GLOBAL},
    {&rdb_drop_idx_psi_thread_key, "drop index", PSI_FLAG_GLOBAL},
};

static void init_rocksdb_psi_keys() {
  const char *const category = "rocksdb";
  int count;

  if (PSI_server == nullptr)
    return;

  count = array_elements(all_rocksdb_mutexes);
  PSI_server->register_mutex(category, all_rocksdb_mutexes, count);

  count = array_elements(all_rocksdb_rwlocks);
  PSI_server->register_rwlock(category, all_rocksdb_rwlocks, count);

  count = array_elements(all_rocksdb_conds);
  // TODO Disabling PFS for conditions due to the bug
  // https://github.com/MySQLOnRocksDB/mysql-5.6/issues/92
  // PSI_server->register_cond(category, all_rocksdb_conds, count);

  count = array_elements(all_rocksdb_stages);
  mysql_stage_register(category, all_rocksdb_stages, count);

  count = array_elements(all_rocksdb_threads);
  mysql_thread_register(category, all_rocksdb_threads, count);
}
#endif

/*
  Drop index thread's control
*/

static Rdb_drop_index_thread rdb_drop_idx_thread;

static void rocksdb_drop_index_wakeup_thread(
    my_core::THD *const thd __attribute__((__unused__)),
    struct st_mysql_sys_var *const var __attribute__((__unused__)),
    void *const var_ptr __attribute__((__unused__)), const void *const save) {
  if (*static_cast<const bool *>(save)) {
    rdb_drop_idx_thread.signal();
  }
}

static inline uint32_t rocksdb_perf_context_level(THD *const thd) {
  DBUG_ASSERT(thd != nullptr);

  const int session_perf_context_level = THDVAR(thd, perf_context_level);
  if (session_perf_context_level > rocksdb::PerfLevel::kUninitialized) {
    return session_perf_context_level;
  }

  /*
    Fallback to global thdvar, if session specific one was not set to a valid
    value.
  */

  const int global_perf_context_level = THDVAR(nullptr, perf_context_level);
  if (global_perf_context_level > rocksdb::PerfLevel::kUninitialized) {
    return global_perf_context_level;
  }

  return rocksdb::PerfLevel::kDisable;
}

/*
  Very short (functor-like) interface to be passed to
  Rdb_transaction::walk_tx_list()
*/

interface Rdb_tx_list_walker {
  virtual ~Rdb_tx_list_walker() {}
  virtual void process_tran(const Rdb_transaction *const) = 0;
};

/*
  This is a helper class that is passed to RocksDB to get notifications when
  a snapshot gets created.
*/

class Rdb_snapshot_notifier : public rocksdb::TransactionNotifier {
  Rdb_transaction *m_owning_tx;

  void SnapshotCreated(const rocksdb::Snapshot *snapshot) override;

public:
  Rdb_snapshot_notifier(const Rdb_snapshot_notifier &) = delete;
  Rdb_snapshot_notifier &operator=(const Rdb_snapshot_notifier &) = delete;

  explicit Rdb_snapshot_notifier(Rdb_transaction *const owning_tx)
      : m_owning_tx(owning_tx) {}

  // If the owning Rdb_transaction gets destructed we need to not reference
  // it anymore.
  void detach() { m_owning_tx = nullptr; }
};

/* This is the base class for transactions when interacting with rocksdb.
*/
class Rdb_transaction {
protected:
  ulonglong m_write_count = 0;
  ulonglong m_lock_count = 0;

  bool m_is_delayed_snapshot = false;
  bool m_is_two_phase = false;

  THD *m_thd = nullptr;

  rocksdb::ReadOptions m_read_opts;

  static std::multiset<Rdb_transaction *> s_tx_list;
  static mysql_mutex_t s_tx_list_mutex;

  Rdb_io_perf *m_tbl_io_perf;

  bool m_tx_read_only = false;

  int m_timeout_sec; /* Cached value of @@rocksdb_lock_wait_timeout */

  /* Maximum number of locks the transaction can have */
  ulonglong m_max_row_locks;

  bool m_is_tx_failed = false;
  bool m_rollback_only = false;

  std::shared_ptr<Rdb_snapshot_notifier> m_notifier;

  // This should be used only when updating binlog information.
  virtual bool commit_no_binlog() = 0;
  virtual rocksdb::Iterator *
  get_iterator(const rocksdb::ReadOptions &options,
               rocksdb::ColumnFamilyHandle *column_family) = 0;

public:
  int64_t m_snapshot_timestamp = 0;
  bool m_ddl_transaction;

  /*
    for distinction between rdb_transaction_impl and rdb_writebatch_impl
    when using walk tx list
  */
  virtual bool is_writebatch_trx() const = 0;

  static void init_mutex() {
    mysql_mutex_init(key_mutex_tx_list, &s_tx_list_mutex, MY_MUTEX_INIT_FAST);
  }

  static void term_mutex() {
    DBUG_ASSERT(s_tx_list.size() == 0);
    mysql_mutex_destroy(&s_tx_list_mutex);
  }

  static void walk_tx_list(Rdb_tx_list_walker *walker) {
    DBUG_ASSERT(walker != nullptr);

    mysql_mutex_lock(&s_tx_list_mutex);
    for (auto it : s_tx_list)
      walker->process_tran(it);
    mysql_mutex_unlock(&s_tx_list_mutex);
  }

  int set_status_error(THD *const thd, const rocksdb::Status &s,
                       const Rdb_key_def &kd, Rdb_tbl_def *const tbl_def) {
    DBUG_ASSERT(!s.ok());
    DBUG_ASSERT(tbl_def != nullptr);

    if (s.IsTimedOut()) {
      /*
        SQL layer has weird expectations. If we return an error when
        doing a read in DELETE IGNORE, it will ignore the error ("because it's
        an IGNORE command!) but then will fail an assert, because "error code
        was returned, but no error happened".  Do what InnoDB's
        convert_error_code_to_mysql() does: force a statement
        rollback before returning HA_ERR_LOCK_WAIT_TIMEOUT:
        */
      my_core::thd_mark_transaction_to_rollback(thd, false /*just statement*/);

      return HA_ERR_LOCK_WAIT_TIMEOUT;
    }

    if (s.IsDeadlock()) {
      my_core::thd_mark_transaction_to_rollback(thd,
                                                false /* just statement */);
      return HA_ERR_LOCK_DEADLOCK;
    } else if (s.IsBusy()) {
      rocksdb_snapshot_conflict_errors++;
      if (rocksdb_print_snapshot_conflict_queries) {
        char user_host_buff[MAX_USER_HOST_SIZE + 1];
        make_user_name(thd, user_host_buff);
        // NO_LINT_DEBUG
        sql_print_warning("Got snapshot conflict errors: User: %s "
                          "Query: %s",
                          user_host_buff, thd->query());
      }
      return HA_ERR_LOCK_DEADLOCK;
    }

    if (s.IsLockLimit()) {
      return HA_ERR_ROCKSDB_TOO_MANY_LOCKS;
    }

    if (s.IsIOError() || s.IsCorruption()) {
      rdb_handle_io_error(s, RDB_IO_ERROR_GENERAL);
    }
    my_error(ER_INTERNAL_ERROR, MYF(0), s.ToString().c_str());
    return HA_ERR_INTERNAL_ERROR;
  }

  THD *get_thd() const { return m_thd; }

  /* Used for tracking io_perf counters */
  void io_perf_start(Rdb_io_perf *const io_perf) {
    /*
      Since perf_context is tracked per thread, it is difficult and expensive
      to maintain perf_context on a per table basis. Therefore, roll all
      perf_context data into the first table used in a query. This works well
      for single table queries and is probably good enough for queries that hit
      multiple tables.

      perf_context stats gathering is started when the table lock is acquired
      or when ha_rocksdb::start_stmt is called in case of LOCK TABLES. They
      are recorded when the table lock is released, or when commit/rollback
      is called on the transaction, whichever comes first. Table lock release
      and commit/rollback can happen in different orders. In the case where
      the lock is released before commit/rollback is called, an extra step to
      gather stats during commit/rollback is needed.
    */
    if (m_tbl_io_perf == nullptr &&
        io_perf->start(rocksdb_perf_context_level(m_thd))) {
      m_tbl_io_perf = io_perf;
    }
  }

  void io_perf_end_and_record(void) {
    if (m_tbl_io_perf != nullptr) {
      m_tbl_io_perf->end_and_record(rocksdb_perf_context_level(m_thd));
      m_tbl_io_perf = nullptr;
    }
  }

  void io_perf_end_and_record(Rdb_io_perf *const io_perf) {
    if (m_tbl_io_perf == io_perf) {
      io_perf_end_and_record();
    }
  }

  void set_params(int timeout_sec_arg, int max_row_locks_arg) {
    m_timeout_sec = timeout_sec_arg;
    m_max_row_locks = max_row_locks_arg;
    set_lock_timeout(timeout_sec_arg);
  }

  virtual void set_lock_timeout(int timeout_sec_arg) = 0;

  ulonglong get_write_count() const { return m_write_count; }

  int get_timeout_sec() const { return m_timeout_sec; }

  ulonglong get_lock_count() const { return m_lock_count; }

  virtual void set_sync(bool sync) = 0;

  virtual void release_lock(rocksdb::ColumnFamilyHandle *const column_family,
                            const std::string &rowkey) = 0;

  virtual bool prepare(const rocksdb::TransactionName &name) = 0;

  bool commit_or_rollback() {
    bool res;
    if (m_is_tx_failed) {
      rollback();
      res = false;
    } else
      res = commit();
    return res;
  }

  bool commit() {
    if (get_write_count() == 0) {
      rollback();
      return false;
    } else if (m_rollback_only) {
      /*
        Transactions marked as rollback_only are expected to be rolled back at
        prepare(). But there are some exceptions like below that prepare() is
        never called and commit() is called instead.
         1. Binlog is disabled
         2. No modification exists in binlog cache for the transaction (#195)
        In both cases, rolling back transaction is safe. Nothing is written to
        binlog.
       */
      my_printf_error(ER_UNKNOWN_ERROR, ERRSTR_ROLLBACK_ONLY, MYF(0));
      rollback();
      return true;
    } else {
      return commit_no_binlog();
    }
  }

  virtual void rollback() = 0;

  void snapshot_created(const rocksdb::Snapshot *const snapshot) {
    DBUG_ASSERT(snapshot != nullptr);

    m_read_opts.snapshot = snapshot;
    rdb->GetEnv()->GetCurrentTime(&m_snapshot_timestamp);
    m_is_delayed_snapshot = false;
  }

  virtual void acquire_snapshot(bool acquire_now) = 0;
  virtual void release_snapshot() = 0;

  bool has_snapshot() const { return m_read_opts.snapshot != nullptr; }

private:
  // The tables we are currently loading.  In a partitioned table this can
  // have more than one entry
  std::vector<ha_rocksdb *> m_curr_bulk_load;

public:
  int finish_bulk_load() {
    int rc = 0;

    std::vector<ha_rocksdb *>::iterator it;
    while ((it = m_curr_bulk_load.begin()) != m_curr_bulk_load.end()) {
      int rc2 = (*it)->finalize_bulk_load();
      if (rc2 != 0 && rc == 0) {
        rc = rc2;
      }
    }

    DBUG_ASSERT(m_curr_bulk_load.size() == 0);

    return rc;
  }

  void start_bulk_load(ha_rocksdb *const bulk_load) {
    /*
     If we already have an open bulk load of a table and the name doesn't
     match the current one, close out the currently running one.  This allows
     multiple bulk loads to occur on a partitioned table, but then closes
     them all out when we switch to another table.
    */
    DBUG_ASSERT(bulk_load != nullptr);

    if (!m_curr_bulk_load.empty() &&
        !bulk_load->same_table(*m_curr_bulk_load[0])) {
      const auto res = finish_bulk_load();
      SHIP_ASSERT(res == 0);
    }

    m_curr_bulk_load.push_back(bulk_load);
  }

  void end_bulk_load(ha_rocksdb *const bulk_load) {
    for (auto it = m_curr_bulk_load.begin(); it != m_curr_bulk_load.end();
         it++) {
      if (*it == bulk_load) {
        m_curr_bulk_load.erase(it);
        return;
      }
    }

    // Should not reach here
    SHIP_ASSERT(0);
  }

  int num_ongoing_bulk_load() const { return m_curr_bulk_load.size(); }

  /*
    Flush the data accumulated so far. This assumes we're doing a bulk insert.

    @detail
      This should work like transaction commit, except that we don't
      synchronize with the binlog (there is no API that would allow to have
      binlog flush the changes accumulated so far and return its current
      position)

    @todo
      Add test coverage for what happens when somebody attempts to do bulk
      inserts while inside a multi-statement transaction.
  */
  bool flush_batch() {
    if (get_write_count() == 0)
      return false;

    /* Commit the current transaction */
    if (commit_no_binlog())
      return true;

    /* Start another one */
    start_tx();
    return false;
  }

  virtual rocksdb::Status put(rocksdb::ColumnFamilyHandle *const column_family,
                              const rocksdb::Slice &key,
                              const rocksdb::Slice &value) = 0;
  virtual rocksdb::Status
  delete_key(rocksdb::ColumnFamilyHandle *const column_family,
             const rocksdb::Slice &key) = 0;
  virtual rocksdb::Status
  single_delete(rocksdb::ColumnFamilyHandle *const column_family,
                const rocksdb::Slice &key) = 0;

  virtual bool has_modifications() const = 0;

  virtual rocksdb::WriteBatchBase *get_indexed_write_batch() = 0;
  /*
    Return a WriteBatch that one can write to. The writes will skip any
    transaction locking. The writes will NOT be visible to the transaction.
  */
  rocksdb::WriteBatchBase *get_blind_write_batch() {
    return get_indexed_write_batch()->GetWriteBatch();
  }

  virtual rocksdb::Status get(rocksdb::ColumnFamilyHandle *const column_family,
                              const rocksdb::Slice &key,
                              std::string *value) const = 0;
  virtual rocksdb::Status
  get_for_update(rocksdb::ColumnFamilyHandle *const column_family,
                 const rocksdb::Slice &key, std::string *const value,
                 bool exclusive) = 0;

  rocksdb::Iterator *
  get_iterator(rocksdb::ColumnFamilyHandle *const column_family,
               bool skip_bloom_filter, bool fill_cache,
               bool read_current = false, bool create_snapshot = true) {
    // Make sure we are not doing both read_current (which implies we don't
    // want a snapshot) and create_snapshot which makes sure we create
    // a snapshot
    DBUG_ASSERT(column_family != nullptr);
    DBUG_ASSERT(!read_current || !create_snapshot);

    if (create_snapshot)
      acquire_snapshot(true);

    rocksdb::ReadOptions options = m_read_opts;

    if (skip_bloom_filter) {
      options.total_order_seek = true;
    } else {
      // With this option, Iterator::Valid() returns false if key
      // is outside of the prefix bloom filter range set at Seek().
      // Must not be set to true if not using bloom filter.
      options.prefix_same_as_start = true;
    }
    options.fill_cache = fill_cache;
    if (read_current) {
      options.snapshot = nullptr;
    }
    return get_iterator(options, column_family);
  }

  virtual bool is_tx_started() const = 0;
  virtual void start_tx() = 0;
  virtual void start_stmt() = 0;
  virtual void rollback_stmt() = 0;

  void set_tx_failed(bool failed_arg) { m_is_tx_failed = failed_arg; }

  bool can_prepare() const {
    if (m_rollback_only) {
      my_printf_error(ER_UNKNOWN_ERROR, ERRSTR_ROLLBACK_ONLY, MYF(0));
      return false;
    }
    return true;
  }

  int rollback_to_savepoint(void *const savepoint) {
    if (has_modifications()) {
      my_printf_error(ER_UNKNOWN_ERROR,
                      "MyRocks currently does not support ROLLBACK TO "
                      "SAVEPOINT if modifying rows.",
                      MYF(0));
      m_rollback_only = true;
      return HA_EXIT_FAILURE;
    }
    return HA_EXIT_SUCCESS;
  }

  /*
    This is used by transactions started with "START TRANSACTION WITH "
    "CONSISTENT [ROCKSDB] SNAPSHOT". When tx_read_only is turned on,
    snapshot has to be created via DB::GetSnapshot(), not via Transaction
    API.
  */
  bool is_tx_read_only() const { return m_tx_read_only; }

  bool is_two_phase() const { return m_is_two_phase; }

  void set_tx_read_only(bool val) { m_tx_read_only = val; }

  explicit Rdb_transaction(THD *const thd)
      : m_thd(thd), m_tbl_io_perf(nullptr) {
    mysql_mutex_lock(&s_tx_list_mutex);
    s_tx_list.insert(this);
    mysql_mutex_unlock(&s_tx_list_mutex);
  }

  virtual ~Rdb_transaction() {
    mysql_mutex_lock(&s_tx_list_mutex);
    s_tx_list.erase(this);
    mysql_mutex_unlock(&s_tx_list_mutex);
  }
};

/*
  This is a rocksdb transaction. Its members represent the current transaction,
  which consists of:
  - the snapshot
  - the changes we've made but are not seeing yet.

  The changes are made to individual tables, which store them here and then
  this object commits them on commit.
*/
class Rdb_transaction_impl : public Rdb_transaction {
  rocksdb::Transaction *m_rocksdb_tx = nullptr;
  rocksdb::Transaction *m_rocksdb_reuse_tx = nullptr;

public:
  void set_lock_timeout(int timeout_sec_arg) override {
    if (m_rocksdb_tx)
      m_rocksdb_tx->SetLockTimeout(rdb_convert_sec_to_ms(m_timeout_sec));
  }

  void set_sync(bool sync) override {
    m_rocksdb_tx->GetWriteOptions()->sync = sync;
  }

  void release_lock(rocksdb::ColumnFamilyHandle *const column_family,
                    const std::string &rowkey) override {
    if (!THDVAR(m_thd, lock_scanned_rows)) {
      m_rocksdb_tx->UndoGetForUpdate(column_family, rocksdb::Slice(rowkey));
    }
  }

  virtual bool is_writebatch_trx() const override { return false; }

private:
  void release_tx(void) {
    // We are done with the current active transaction object.  Preserve it
    // for later reuse.
    DBUG_ASSERT(m_rocksdb_reuse_tx == nullptr);
    m_rocksdb_reuse_tx = m_rocksdb_tx;
    m_rocksdb_tx = nullptr;
  }

  bool prepare(const rocksdb::TransactionName &name) override {
    rocksdb::Status s;
    s = m_rocksdb_tx->SetName(name);
    if (!s.ok()) {
      rdb_handle_io_error(s, RDB_IO_ERROR_TX_COMMIT);
      return false;
    }

    s = m_rocksdb_tx->Prepare();
    if (!s.ok()) {
      rdb_handle_io_error(s, RDB_IO_ERROR_TX_COMMIT);
      return false;
    }
    return true;
  }

  bool commit_no_binlog() override {
    bool res = false;
    release_snapshot();
    const rocksdb::Status s = m_rocksdb_tx->Commit();
    if (!s.ok()) {
      rdb_handle_io_error(s, RDB_IO_ERROR_TX_COMMIT);
      res = true;
    }

    /* Save the transaction object to be reused */
    release_tx();

    m_write_count = 0;
    m_lock_count = 0;
    set_tx_read_only(false);
    m_rollback_only = false;
    return res;
  }

public:
  void rollback() override {
    m_write_count = 0;
    m_lock_count = 0;
    m_ddl_transaction = false;
    if (m_rocksdb_tx) {
      release_snapshot();
      /* This will also release all of the locks: */
      m_rocksdb_tx->Rollback();

      /* Save the transaction object to be reused */
      release_tx();

      set_tx_read_only(false);
      m_rollback_only = false;
    }
  }

  void acquire_snapshot(bool acquire_now) override {
    if (m_read_opts.snapshot == nullptr) {
      if (is_tx_read_only()) {
        snapshot_created(rdb->GetSnapshot());
      } else if (acquire_now) {
        m_rocksdb_tx->SetSnapshot();
        snapshot_created(m_rocksdb_tx->GetSnapshot());
      } else if (!m_is_delayed_snapshot) {
        m_rocksdb_tx->SetSnapshotOnNextOperation(m_notifier);
        m_is_delayed_snapshot = true;
      }
    }
  }

  void release_snapshot() override {
    bool need_clear = m_is_delayed_snapshot;

    if (m_read_opts.snapshot != nullptr) {
      m_snapshot_timestamp = 0;
      if (is_tx_read_only()) {
        rdb->ReleaseSnapshot(m_read_opts.snapshot);
        need_clear = false;
      } else {
        need_clear = true;
      }
      m_read_opts.snapshot = nullptr;
    }

    if (need_clear && m_rocksdb_tx != nullptr)
      m_rocksdb_tx->ClearSnapshot();
  }

  bool has_snapshot() { return m_read_opts.snapshot != nullptr; }

  rocksdb::Status put(rocksdb::ColumnFamilyHandle *const column_family,
                      const rocksdb::Slice &key,
                      const rocksdb::Slice &value) override {
    ++m_write_count;
    ++m_lock_count;
    if (m_write_count > m_max_row_locks || m_lock_count > m_max_row_locks)
      return rocksdb::Status::Aborted(rocksdb::Status::kLockLimit);
    return m_rocksdb_tx->Put(column_family, key, value);
  }

  rocksdb::Status delete_key(rocksdb::ColumnFamilyHandle *const column_family,
                             const rocksdb::Slice &key) override {
    ++m_write_count;
    ++m_lock_count;
    if (m_write_count > m_max_row_locks || m_lock_count > m_max_row_locks)
      return rocksdb::Status::Aborted(rocksdb::Status::kLockLimit);
    return m_rocksdb_tx->Delete(column_family, key);
  }

  rocksdb::Status
  single_delete(rocksdb::ColumnFamilyHandle *const column_family,
                const rocksdb::Slice &key) override {
    ++m_write_count;
    ++m_lock_count;
    if (m_write_count > m_max_row_locks || m_lock_count > m_max_row_locks)
      return rocksdb::Status::Aborted(rocksdb::Status::kLockLimit);
    return m_rocksdb_tx->SingleDelete(column_family, key);
  }

  bool has_modifications() const override {
    return m_rocksdb_tx->GetWriteBatch() &&
           m_rocksdb_tx->GetWriteBatch()->GetWriteBatch() &&
           m_rocksdb_tx->GetWriteBatch()->GetWriteBatch()->Count() > 0;
  }

  /*
    Return a WriteBatch that one can write to. The writes will skip any
    transaction locking. The writes WILL be visible to the transaction.
  */
  rocksdb::WriteBatchBase *get_indexed_write_batch() override {
    ++m_write_count;
    return m_rocksdb_tx->GetWriteBatch();
  }

  rocksdb::Status get(rocksdb::ColumnFamilyHandle *const column_family,
                      const rocksdb::Slice &key,
                      std::string *value) const override {
    return m_rocksdb_tx->Get(m_read_opts, column_family, key, value);
  }

  rocksdb::Status
  get_for_update(rocksdb::ColumnFamilyHandle *const column_family,
                 const rocksdb::Slice &key, std::string *const value,
                 bool exclusive) override {
    if (++m_lock_count > m_max_row_locks)
      return rocksdb::Status::Aborted(rocksdb::Status::kLockLimit);

    return m_rocksdb_tx->GetForUpdate(m_read_opts, column_family, key, value,
                                      exclusive);
  }

  rocksdb::Iterator *
  get_iterator(const rocksdb::ReadOptions &options,
               rocksdb::ColumnFamilyHandle *const column_family) override {
    return m_rocksdb_tx->GetIterator(options, column_family);
  }

  const rocksdb::Transaction *get_rdb_trx() const { return m_rocksdb_tx; }

  bool is_tx_started() const override { return (m_rocksdb_tx != nullptr); }

  void start_tx() override {
    rocksdb::TransactionOptions tx_opts;
    rocksdb::WriteOptions write_opts;
    tx_opts.set_snapshot = false;
    tx_opts.lock_timeout = rdb_convert_sec_to_ms(m_timeout_sec);
    tx_opts.deadlock_detect = THDVAR(m_thd, deadlock_detect);

    write_opts.sync = THDVAR(m_thd, write_sync);
    write_opts.disableWAL = THDVAR(m_thd, write_disable_wal);
    write_opts.ignore_missing_column_families =
        THDVAR(m_thd, write_ignore_missing_column_families);
    m_is_two_phase = rocksdb_enable_2pc;

    /*
      If m_rocksdb_reuse_tx is null this will create a new transaction object.
      Otherwise it will reuse the existing one.
    */
    m_rocksdb_tx =
        rdb->BeginTransaction(write_opts, tx_opts, m_rocksdb_reuse_tx);
    m_rocksdb_reuse_tx = nullptr;

    m_read_opts = rocksdb::ReadOptions();

    m_ddl_transaction = false;
  }

  /*
    Start a statement inside a multi-statement transaction.

    @todo: are we sure this is called once (and not several times) per
    statement start?

    For hooking to start of statement that is its own transaction, see
    ha_rocksdb::external_lock().
  */
  void start_stmt() override {
    // Set the snapshot to delayed acquisition (SetSnapshotOnNextOperation)
    acquire_snapshot(false);
    m_rocksdb_tx->SetSavePoint();
  }

  /*
    This must be called when last statement is rolled back, but the transaction
    continues
  */
  void rollback_stmt() override {
    /* TODO: here we must release the locks taken since the start_stmt() call */
    if (m_rocksdb_tx) {
      const rocksdb::Snapshot *const org_snapshot = m_rocksdb_tx->GetSnapshot();
      m_rocksdb_tx->RollbackToSavePoint();

      const rocksdb::Snapshot *const cur_snapshot = m_rocksdb_tx->GetSnapshot();
      if (org_snapshot != cur_snapshot) {
        if (org_snapshot != nullptr)
          m_snapshot_timestamp = 0;

        m_read_opts.snapshot = cur_snapshot;
        if (cur_snapshot != nullptr)
          rdb->GetEnv()->GetCurrentTime(&m_snapshot_timestamp);
        else
          m_is_delayed_snapshot = true;
      }
    }
  }

  explicit Rdb_transaction_impl(THD *const thd)
      : Rdb_transaction(thd), m_rocksdb_tx(nullptr) {
    // Create a notifier that can be called when a snapshot gets generated.
    m_notifier = std::make_shared<Rdb_snapshot_notifier>(this);
  }

  virtual ~Rdb_transaction_impl() {
    rollback();

    // Theoretically the notifier could outlive the Rdb_transaction_impl
    // (because of the shared_ptr), so let it know it can't reference
    // the transaction anymore.
    m_notifier->detach();

    // Free any transaction memory that is still hanging around.
    delete m_rocksdb_reuse_tx;
    DBUG_ASSERT(m_rocksdb_tx == nullptr);
  }
};

/* This is a rocksdb write batch. This class doesn't hold or wait on any
   transaction locks (skips rocksdb transaction API) thus giving better
   performance. The commit is done through rdb->GetBaseDB()->Commit().

   Currently this is only used for replication threads which are guaranteed
   to be non-conflicting. Any further usage of this class should completely
   be thought thoroughly.
*/
class Rdb_writebatch_impl : public Rdb_transaction {
  rocksdb::WriteBatchWithIndex *m_batch;
  rocksdb::WriteOptions write_opts;
  // Called after commit/rollback.
  void reset() {
    m_batch->Clear();
    m_read_opts = rocksdb::ReadOptions();
    m_ddl_transaction = false;
  }

private:
  bool prepare(const rocksdb::TransactionName &name) override { return true; }

  bool commit_no_binlog() override {
    bool res = false;
    release_snapshot();
    const rocksdb::Status s =
        rdb->GetBaseDB()->Write(write_opts, m_batch->GetWriteBatch());
    if (!s.ok()) {
      rdb_handle_io_error(s, RDB_IO_ERROR_TX_COMMIT);
      res = true;
    }
    reset();

    m_write_count = 0;
    set_tx_read_only(false);
    m_rollback_only = false;
    return res;
  }

public:
  bool is_writebatch_trx() const override { return true; }

  void set_lock_timeout(int timeout_sec_arg) override {
    // Nothing to do here.
  }

  void set_sync(bool sync) override { write_opts.sync = sync; }

  void release_lock(rocksdb::ColumnFamilyHandle *const column_family,
                    const std::string &rowkey) override {
    // Nothing to do here since we don't hold any row locks.
  }

  void rollback() override {
    m_write_count = 0;
    m_lock_count = 0;
    release_snapshot();

    reset();
    set_tx_read_only(false);
    m_rollback_only = false;
  }

  void acquire_snapshot(bool acquire_now) override {
    if (m_read_opts.snapshot == nullptr)
      snapshot_created(rdb->GetSnapshot());
  }

  void release_snapshot() override {
    if (m_read_opts.snapshot != nullptr) {
      rdb->ReleaseSnapshot(m_read_opts.snapshot);
      m_read_opts.snapshot = nullptr;
    }
  }

  rocksdb::Status put(rocksdb::ColumnFamilyHandle *const column_family,
                      const rocksdb::Slice &key,
                      const rocksdb::Slice &value) override {
    ++m_write_count;
    m_batch->Put(column_family, key, value);
    // Note Put/Delete in write batch doesn't return any error code. We simply
    // return OK here.
    return rocksdb::Status::OK();
  }

  rocksdb::Status delete_key(rocksdb::ColumnFamilyHandle *const column_family,
                             const rocksdb::Slice &key) override {
    ++m_write_count;
    m_batch->Delete(column_family, key);
    return rocksdb::Status::OK();
  }

  rocksdb::Status
  single_delete(rocksdb::ColumnFamilyHandle *const column_family,
                const rocksdb::Slice &key) override {
    ++m_write_count;
    m_batch->SingleDelete(column_family, key);
    return rocksdb::Status::OK();
  }

  bool has_modifications() const override {
    return m_batch->GetWriteBatch()->Count() > 0;
  }

  rocksdb::WriteBatchBase *get_indexed_write_batch() override {
    ++m_write_count;
    return m_batch;
  }

  rocksdb::Status get(rocksdb::ColumnFamilyHandle *const column_family,
                      const rocksdb::Slice &key,
                      std::string *const value) const override {
    return m_batch->GetFromBatchAndDB(rdb, m_read_opts, column_family, key,
                                      value);
  }

  rocksdb::Status
  get_for_update(rocksdb::ColumnFamilyHandle *const column_family,
                 const rocksdb::Slice &key, std::string *const value,
                 bool exclusive) override {
    return get(column_family, key, value);
  }

  rocksdb::Iterator *
  get_iterator(const rocksdb::ReadOptions &options,
               rocksdb::ColumnFamilyHandle *const column_family) override {
    const auto it = rdb->NewIterator(options);
    return m_batch->NewIteratorWithBase(it);
  }

  bool is_tx_started() const override { return (m_batch != nullptr); }

  void start_tx() override {
    reset();
    write_opts.sync = THDVAR(m_thd, write_sync);
    write_opts.disableWAL = THDVAR(m_thd, write_disable_wal);
    write_opts.ignore_missing_column_families =
        THDVAR(m_thd, write_ignore_missing_column_families);
  }

  void start_stmt() override { m_batch->SetSavePoint(); }

  void rollback_stmt() override {
    if (m_batch)
      m_batch->RollbackToSavePoint();
  }

  explicit Rdb_writebatch_impl(THD *const thd)
      : Rdb_transaction(thd), m_batch(nullptr) {
    m_batch = new rocksdb::WriteBatchWithIndex(rocksdb::BytewiseComparator(), 0,
                                               true);
  }

  virtual ~Rdb_writebatch_impl() {
    rollback();
    delete m_batch;
  }
};

void Rdb_snapshot_notifier::SnapshotCreated(
    const rocksdb::Snapshot *const snapshot) {
  if (m_owning_tx != nullptr) {
    m_owning_tx->snapshot_created(snapshot);
  }
}

std::multiset<Rdb_transaction *> Rdb_transaction::s_tx_list;
mysql_mutex_t Rdb_transaction::s_tx_list_mutex;

static Rdb_transaction *&get_tx_from_thd(THD *const thd) {
  return *reinterpret_cast<Rdb_transaction **>(
      my_core::thd_ha_data(thd, rocksdb_hton));
}

namespace {

class Rdb_perf_context_guard {
  Rdb_io_perf m_io_perf;
  THD *m_thd;

public:
  Rdb_perf_context_guard(const Rdb_perf_context_guard &) = delete;
  Rdb_perf_context_guard &operator=(const Rdb_perf_context_guard &) = delete;

  explicit Rdb_perf_context_guard(THD *const thd) : m_thd(thd) {
    Rdb_transaction *&tx = get_tx_from_thd(m_thd);
    /*
      if perf_context information is already being recorded, this becomes a
      no-op
    */
    if (tx != nullptr) {
      tx->io_perf_start(&m_io_perf);
    }
  }

  ~Rdb_perf_context_guard() {
    Rdb_transaction *&tx = get_tx_from_thd(m_thd);
    if (tx != nullptr) {
      tx->io_perf_end_and_record();
    }
  }
};

} // anonymous namespace

/*
  TODO: maybe, call this in external_lock() and store in ha_rocksdb..
*/

static Rdb_transaction *get_or_create_tx(THD *const thd) {
  Rdb_transaction *&tx = get_tx_from_thd(thd);
  // TODO: this is called too many times.. O(#rows)
  if (tx == nullptr) {
    if (rpl_skip_tx_api_var && thd->rli_slave)
      tx = new Rdb_writebatch_impl(thd);
    else
      tx = new Rdb_transaction_impl(thd);
    tx->set_params(THDVAR(thd, lock_wait_timeout), THDVAR(thd, max_row_locks));
    tx->start_tx();
  } else {
    tx->set_params(THDVAR(thd, lock_wait_timeout), THDVAR(thd, max_row_locks));
    if (!tx->is_tx_started()) {
      tx->start_tx();
    }
  }

  return tx;
}

static int rocksdb_close_connection(handlerton *const hton, THD *const thd) {
  Rdb_transaction *&tx = get_tx_from_thd(thd);
  if (tx != nullptr) {
    int rc = tx->finish_bulk_load();
    if (rc != 0) {
      // NO_LINT_DEBUG
      sql_print_error("RocksDB: Error %d finalizing last SST file while "
                      "disconnecting",
                      rc);
      abort_with_stack_traces();
    }

    delete tx;
    tx = nullptr;
  }
  return HA_EXIT_SUCCESS;
}

/*
 * Serializes an xid to a string so that it can
 * be used as a rocksdb transaction name
 */
static std::string rdb_xid_to_string(const XID &src) {
  DBUG_ASSERT(src.gtrid_length >= 0 && src.gtrid_length <= MAXGTRIDSIZE);
  DBUG_ASSERT(src.bqual_length >= 0 && src.bqual_length <= MAXBQUALSIZE);

  std::string buf;
  buf.reserve(RDB_XIDHDR_LEN + src.gtrid_length + src.bqual_length);

  /*
   * expand formatID to fill 8 bytes if it doesn't already
   * then reinterpret bit pattern as unsigned and store in network order
   */
  uchar fidbuf[RDB_FORMATID_SZ];
  int64 signed_fid8 = src.formatID;
  const uint64 raw_fid8 = *reinterpret_cast<uint64 *>(&signed_fid8);
  rdb_netbuf_store_uint64(fidbuf, raw_fid8);
  buf.append(reinterpret_cast<const char *>(fidbuf), RDB_FORMATID_SZ);

  buf.push_back(src.gtrid_length);
  buf.push_back(src.bqual_length);
  buf.append(src.data, (src.gtrid_length) + (src.bqual_length));
  return buf;
}

/**
  Called by hton->flush_logs after MySQL group commit prepares a set of
  transactions.
*/
static bool rocksdb_flush_wal(handlerton *const hton
                              __attribute__((__unused__))) {
  DBUG_ASSERT(rdb != nullptr);
  rocksdb_wal_group_syncs++;
  const rocksdb::Status s = rdb->SyncWAL();
  if (!s.ok()) {
    return HA_EXIT_FAILURE;
  }
  return HA_EXIT_SUCCESS;
}

/**
  For a slave, prepare() updates the slave_gtid_info table which tracks the
  replication progress.
*/
static int rocksdb_prepare(handlerton *const hton, THD *const thd,
                           bool prepare_tx) {
  Rdb_transaction *&tx = get_tx_from_thd(thd);
  if (!tx->can_prepare()) {
    return HA_EXIT_FAILURE;
  }
  if (prepare_tx ||
      (!my_core::thd_test_options(thd, OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN))) {

    if (tx->is_two_phase()) {
      if (thd->durability_property == HA_IGNORE_DURABILITY) {
        tx->set_sync(false);
      }
      XID xid;
      thd_get_xid(thd, reinterpret_cast<MYSQL_XID *>(&xid));
      if (!tx->prepare(rdb_xid_to_string(xid))) {
        return HA_EXIT_FAILURE;
      }
    }

    DEBUG_SYNC(thd, "rocksdb.prepared");
  }

  return HA_EXIT_SUCCESS;
}

/**
 do nothing for prepare/commit by xid
 this is needed to avoid crashes in XA scenarios
*/
static int rocksdb_commit_by_xid(handlerton *const hton, XID *const xid) {
  const auto name = rdb_xid_to_string(*xid);
  rocksdb::Transaction *const trx = rdb->GetTransactionByName(name);
  if (trx == nullptr) {
    return HA_EXIT_FAILURE;
  }
  const rocksdb::Status s = trx->Commit();
  if (!s.ok()) {
    return HA_EXIT_FAILURE;
  }
  delete trx;
  return HA_EXIT_SUCCESS;
}

static int rocksdb_rollback_by_xid(handlerton *const hton
                                   __attribute__((__unused__)),
                                   XID *const xid) {
  const auto name = rdb_xid_to_string(*xid);
  rocksdb::Transaction *const trx = rdb->GetTransactionByName(name);
  if (trx == nullptr) {
    return HA_EXIT_FAILURE;
  }
  const rocksdb::Status s = trx->Rollback();
  if (!s.ok()) {
    return HA_EXIT_FAILURE;
  }
  delete trx;
  return HA_EXIT_SUCCESS;
}

/**
  Rebuilds an XID from a serialized version stored in a string.
*/
static void rdb_xid_from_string(const std::string &src, XID *const dst) {
  DBUG_ASSERT(dst != nullptr);
  uint offset = 0;
  uint64 raw_fid8 =
      rdb_netbuf_to_uint64(reinterpret_cast<const uchar *>(src.data()));
  const int64 signed_fid8 = *reinterpret_cast<int64 *>(&raw_fid8);
  dst->formatID = signed_fid8;
  offset += RDB_FORMATID_SZ;
  dst->gtrid_length = src.at(offset);
  offset += RDB_GTRID_SZ;
  dst->bqual_length = src.at(offset);
  offset += RDB_BQUAL_SZ;

  DBUG_ASSERT(dst->gtrid_length >= 0 && dst->gtrid_length <= MAXGTRIDSIZE);
  DBUG_ASSERT(dst->bqual_length >= 0 && dst->bqual_length <= MAXBQUALSIZE);

  src.copy(dst->data, (dst->gtrid_length) + (dst->bqual_length),
           RDB_XIDHDR_LEN);
}

/**
  Reading last committed binary log info from RocksDB system row.
  The info is needed for crash safe slave/master to work.
*/
static int rocksdb_recover(handlerton *const hton, XID *const xid_list,
                           uint len) {
  if (len == 0 || xid_list == nullptr) {
    return HA_EXIT_SUCCESS;
  }

  std::vector<rocksdb::Transaction *> trans_list;
  rdb->GetAllPreparedTransactions(&trans_list);

  uint count = 0;
  for (auto &trans : trans_list) {
    if (count >= len) {
      break;
    }
    auto name = trans->GetName();
    rdb_xid_from_string(name, &xid_list[count]);
    count++;
  }
  return count;
}

static int rocksdb_commit(handlerton *const hton, THD *const thd,
                          bool commit_tx) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(hton != nullptr);
  DBUG_ASSERT(thd != nullptr);

  /* this will trigger saving of perf_context information */
  Rdb_perf_context_guard guard(thd);

  /* note: h->external_lock(F_UNLCK) is called after this function is called) */
  Rdb_transaction *&tx = get_tx_from_thd(thd);

  if (tx != nullptr) {
    if (commit_tx || (!my_core::thd_test_options(thd, OPTION_NOT_AUTOCOMMIT |
                                                          OPTION_BEGIN))) {
      /*
        We get here
         - For a COMMIT statement that finishes a multi-statement transaction
         - For a statement that has its own transaction
      */
      if (tx->commit())
        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
    } else {
      /*
        We get here when committing a statement within a transaction.

        We don't need to do anything here. tx->start_stmt() will notify
        Rdb_transaction_impl that another statement has started.
      */
      tx->set_tx_failed(false);
    }

    if (my_core::thd_tx_isolation(thd) <= ISO_READ_COMMITTED) {
      // For READ_COMMITTED, we release any existing snapshot so that we will
      // see any changes that occurred since the last statement.
      tx->release_snapshot();
    }
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

static int rocksdb_rollback(handlerton *const hton, THD *const thd,
                            bool rollback_tx) {
  Rdb_perf_context_guard guard(thd);
  Rdb_transaction *&tx = get_tx_from_thd(thd);

  if (tx != nullptr) {
    if (rollback_tx) {
      /*
        We get here, when
        - ROLLBACK statement is issued.

        Discard the changes made by the transaction
      */
      tx->rollback();
    } else {
      /*
        We get here when
        - a statement with AUTOCOMMIT=1 is being rolled back (because of some
          error)
        - a statement inside a transaction is rolled back
      */

      tx->rollback_stmt();
      tx->set_tx_failed(true);
    }

    if (my_core::thd_tx_isolation(thd) <= ISO_READ_COMMITTED) {
      // For READ_COMMITTED, we release any existing snapshot so that we will
      // see any changes that occurred since the last statement.
      tx->release_snapshot();
    }
  }
  return HA_EXIT_SUCCESS;
}

static bool print_stats(THD *const thd, std::string const &type,
                        std::string const &name, std::string const &status,
                        stat_print_fn *stat_print) {
  return stat_print(thd, type.c_str(), type.size(), name.c_str(), name.size(),
                    status.c_str(), status.size());
}

static std::string format_string(const char *const format, ...) {
  std::string res;
  va_list args;
  va_list args_copy;
  char static_buff[256];

  DBUG_ASSERT(format != nullptr);

  va_start(args, format);
  va_copy(args_copy, args);

  // Calculate how much space we will need
  int len = vsnprintf(nullptr, 0, format, args);
  va_end(args);

  if (len < 0) {
    res = std::string("<format error>");
  } else if (len == 0) {
    // Shortcut for an empty string
    res = std::string("");
  } else {
    // For short enough output use a static buffer
    char *buff = static_buff;
    std::unique_ptr<char[]> dynamic_buff = nullptr;

    len++; // Add one for null terminator

    // for longer output use an allocated buffer
    if (static_cast<uint>(len) > sizeof(static_buff)) {
      dynamic_buff.reset(new char[len]);
      buff = dynamic_buff.get();
    }

    // Now re-do the vsnprintf with the buffer which is now large enough
    (void)vsnprintf(buff, len, format, args_copy);

    // Convert to a std::string.  Note we could have created a std::string
    // large enough and then converted the buffer to a 'char*' and created
    // the output in place.  This would probably work but feels like a hack.
    // Since this isn't code that needs to be super-performant we are going
    // with this 'safer' method.
     res = std::string(buff);
  }

  va_end(args_copy);

  return res;
}

class Rdb_snapshot_status : public Rdb_tx_list_walker {
private:
  std::string m_data;

  static std::string current_timestamp(void) {
    static const char *const format = "%d-%02d-%02d %02d:%02d:%02d";
    time_t currtime;
    struct tm currtm;

    time(&currtime);

    localtime_r(&currtime, &currtm);

    return format_string(format, currtm.tm_year + 1900, currtm.tm_mon + 1,
                         currtm.tm_mday, currtm.tm_hour, currtm.tm_min,
                         currtm.tm_sec);
  }

  static std::string get_header(void) {
    return "\n============================================================\n" +
           current_timestamp() +
           " ROCKSDB TRANSACTION MONITOR OUTPUT\n"
           "============================================================\n"
           "---------\n"
           "SNAPSHOTS\n"
           "---------\n"
           "LIST OF SNAPSHOTS FOR EACH SESSION:\n";
  }

  static std::string get_footer(void) {
    return "-----------------------------------------\n"
           "END OF ROCKSDB TRANSACTION MONITOR OUTPUT\n"
           "=========================================\n";
  }

public:
  Rdb_snapshot_status() : m_data(get_header()) {}

  std::string getResult() { return m_data + get_footer(); }

  /* Implement Rdb_transaction interface */
  /* Create one row in the snapshot status table */
  void process_tran(const Rdb_transaction *const tx) override {
    DBUG_ASSERT(tx != nullptr);

    /* Calculate the duration the snapshot has existed */
    int64_t snapshot_timestamp = tx->m_snapshot_timestamp;
    if (snapshot_timestamp != 0) {
      int64_t curr_time;
      rdb->GetEnv()->GetCurrentTime(&curr_time);

      THD *thd = tx->get_thd();
      char buffer[1024];
      thd_security_context(thd, buffer, sizeof buffer, 0);
      m_data += format_string("---SNAPSHOT, ACTIVE %lld sec\n"
                              "%s\n"
                              "lock count %llu, write count %llu\n",
                              curr_time - snapshot_timestamp, buffer,
                              tx->get_lock_count(), tx->get_write_count());
    }
  }
};

/**
 * @brief
 * walks through all non-replication transactions and copies
 * out relevant information for information_schema.rocksdb_trx
 */
class Rdb_trx_info_aggregator : public Rdb_tx_list_walker {
private:
  std::vector<Rdb_trx_info> *m_trx_info;

public:
  explicit Rdb_trx_info_aggregator(std::vector<Rdb_trx_info> *const trx_info)
      : m_trx_info(trx_info) {}

  void process_tran(const Rdb_transaction *const tx) override {
    static const std::map<int, std::string> state_map = {
        {rocksdb::Transaction::STARTED, "STARTED"},
        {rocksdb::Transaction::AWAITING_PREPARE, "AWAITING_PREPARE"},
        {rocksdb::Transaction::PREPARED, "PREPARED"},
        {rocksdb::Transaction::AWAITING_COMMIT, "AWAITING_COMMIT"},
        {rocksdb::Transaction::COMMITED, "COMMITED"},
        {rocksdb::Transaction::AWAITING_ROLLBACK, "AWAITING_ROLLBACK"},
        {rocksdb::Transaction::ROLLEDBACK, "ROLLEDBACK"},
    };

    DBUG_ASSERT(tx != nullptr);

    THD *const thd = tx->get_thd();
    ulong thread_id = thd->thread_id;

    if (tx->is_writebatch_trx()) {
      const auto wb_impl = static_cast<const Rdb_writebatch_impl *>(tx);
      DBUG_ASSERT(wb_impl);
      m_trx_info->push_back(
          {"",                            /* name */
           0,                             /* trx_id */
           wb_impl->get_write_count(), 0, /* lock_count */
           0,                             /* timeout_sec */
           "",                            /* state */
           "",                            /* waiting_key */
           0,                             /* waiting_cf_id */
           1,                             /*is_replication */
           1,                             /* skip_trx_api */
           wb_impl->is_tx_read_only(), 0, /* deadlock detection */
           wb_impl->num_ongoing_bulk_load(), thread_id, "" /* query string */});
    } else {
      const auto tx_impl = static_cast<const Rdb_transaction_impl *>(tx);
      DBUG_ASSERT(tx_impl);
      const rocksdb::Transaction *rdb_trx = tx_impl->get_rdb_trx();

      if (rdb_trx == nullptr) {
        return;
      }

      std::string query_str;
      LEX_STRING *const lex_str = thd_query_string(thd);
      if (lex_str != nullptr && lex_str->str != nullptr) {
        query_str = std::string(lex_str->str);
      }

      const auto state_it = state_map.find(rdb_trx->GetState());
      DBUG_ASSERT(state_it != state_map.end());
      const int is_replication = (thd->rli_slave != nullptr);
      uint32_t waiting_cf_id;
      std::string waiting_key;
      rdb_trx->GetWaitingTxns(&waiting_cf_id, &waiting_key),

          m_trx_info->push_back(
              {rdb_trx->GetName(), rdb_trx->GetID(), tx_impl->get_write_count(),
               tx_impl->get_lock_count(), tx_impl->get_timeout_sec(),
               state_it->second, waiting_key, waiting_cf_id, is_replication,
               0, /* skip_trx_api */
               tx_impl->is_tx_read_only(), rdb_trx->IsDeadlockDetect(),
               tx_impl->num_ongoing_bulk_load(), thread_id, query_str});
    }
  }
};

/*
  returns a vector of info for all non-replication threads
  for use by information_schema.rocksdb_trx
*/
std::vector<Rdb_trx_info> rdb_get_all_trx_info() {
  std::vector<Rdb_trx_info> trx_info;
  Rdb_trx_info_aggregator trx_info_agg(&trx_info);
  Rdb_transaction::walk_tx_list(&trx_info_agg);
  return trx_info;
}

/* Generate the snapshot status table */
static bool rocksdb_show_snapshot_status(handlerton *const hton, THD *const thd,
                                         stat_print_fn *const stat_print) {
  Rdb_snapshot_status showStatus;

  Rdb_transaction::walk_tx_list(&showStatus);

  /* Send the result data back to MySQL */
  return print_stats(thd, "SNAPSHOTS", "rocksdb", showStatus.getResult(),
                     stat_print);
}

/*
  This is called for SHOW ENGINE ROCKSDB STATUS|LOGS|etc.

  For now, produce info about live files (which gives an imprecise idea about
  what column families are there)
*/

static bool rocksdb_show_status(handlerton *const hton, THD *const thd,
                                stat_print_fn *const stat_print,
                                enum ha_stat_type stat_type) {
  bool res = false;
  if (stat_type == HA_ENGINE_STATUS) {
    std::string str;

    /* Per DB stats */
    if (rdb->GetProperty("rocksdb.dbstats", &str)) {
      res |= print_stats(thd, "DBSTATS", "rocksdb", str, stat_print);
    }

    /* Per column family stats */
    for (const auto &cf_name : cf_manager.get_cf_names()) {
      rocksdb::ColumnFamilyHandle *cfh;
      bool is_automatic;

      /*
        Only the cf name is important. Whether it was generated automatically
        does not matter, so is_automatic is ignored.
      */
      cfh = cf_manager.get_cf(cf_name.c_str(), "", nullptr, &is_automatic);
      if (cfh == nullptr)
        continue;

      if (!rdb->GetProperty(cfh, "rocksdb.cfstats", &str))
        continue;

      res |= print_stats(thd, "CF_COMPACTION", cf_name, str, stat_print);
    }

    /* Memory Statistics */
    std::vector<rocksdb::DB *> dbs;
    std::unordered_set<const rocksdb::Cache *> cache_set;
    size_t internal_cache_count = 0;
    size_t kDefaultInternalCacheSize = 8 * 1024 * 1024;
    char buf[100];

    dbs.push_back(rdb);
    cache_set.insert(rocksdb_tbl_options.block_cache.get());
    for (const auto &cf_handle : cf_manager.get_all_cf()) {
      rocksdb::ColumnFamilyDescriptor cf_desc;
      cf_handle->GetDescriptor(&cf_desc);
      auto *const table_factory = cf_desc.options.table_factory.get();
      if (table_factory != nullptr) {
        std::string tf_name = table_factory->Name();
        if (tf_name.find("BlockBasedTable") != std::string::npos) {
          const rocksdb::BlockBasedTableOptions *const bbt_opt =
              reinterpret_cast<rocksdb::BlockBasedTableOptions *>(
                  table_factory->GetOptions());
          if (bbt_opt != nullptr) {
            if (bbt_opt->block_cache.get() != nullptr) {
              cache_set.insert(bbt_opt->block_cache.get());
            } else {
              internal_cache_count++;
            }
            cache_set.insert(bbt_opt->block_cache_compressed.get());
          }
        }
      }
    }

    std::map<rocksdb::MemoryUtil::UsageType, uint64_t> temp_usage_by_type;
    str.clear();
    rocksdb::MemoryUtil::GetApproximateMemoryUsageByType(dbs, cache_set,
                                                         &temp_usage_by_type);
    snprintf(buf, sizeof(buf), "\nMemTable Total: %lu",
             temp_usage_by_type[rocksdb::MemoryUtil::kMemTableTotal]);
    str.append(buf);
    snprintf(buf, sizeof(buf), "\nMemTable Unflushed: %lu",
             temp_usage_by_type[rocksdb::MemoryUtil::kMemTableUnFlushed]);
    str.append(buf);
    snprintf(buf, sizeof(buf), "\nTable Readers Total: %lu",
             temp_usage_by_type[rocksdb::MemoryUtil::kTableReadersTotal]);
    str.append(buf);
    snprintf(buf, sizeof(buf), "\nCache Total: %lu",
             temp_usage_by_type[rocksdb::MemoryUtil::kCacheTotal]);
    str.append(buf);
    snprintf(buf, sizeof(buf), "\nDefault Cache Capacity: %lu",
             internal_cache_count * kDefaultInternalCacheSize);
    str.append(buf);
    res |= print_stats(thd, "Memory_Stats", "rocksdb", str, stat_print);
  }

  return res;
}

static inline void rocksdb_register_tx(handlerton *const hton, THD *const thd,
                                       Rdb_transaction *const tx) {
  DBUG_ASSERT(tx != nullptr);

  trans_register_ha(thd, FALSE, rocksdb_hton);
  if (my_core::thd_test_options(thd, OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN)) {
    tx->start_stmt();
    trans_register_ha(thd, TRUE, rocksdb_hton);
  }
}

/*
    Supporting START TRANSACTION WITH CONSISTENT SNAPSHOT

    - START TRANSACTION WITH CONSISTENT SNAPSHOT
    takes both InnoDB and RocksDB snapshots, and both InnoDB and RocksDB
    participate in transaction. When executing COMMIT, both InnoDB and
    RocksDB modifications are committed. Remember that XA is not supported yet,
    so mixing engines is not recommended anyway.
*/
static int rocksdb_start_tx_and_assign_read_view(
    handlerton *const hton,          /*!< in: RocksDB handlerton */
    THD *const thd)                  /*!< in: MySQL thread handle of the
                                     user for whom the transaction should
                                     be committed */
{
  Rdb_perf_context_guard guard(thd);

  ulong const tx_isolation = my_core::thd_tx_isolation(thd);

  Rdb_transaction* tx= get_or_create_tx(thd);
  DBUG_ASSERT(!tx->has_snapshot());
  tx->set_tx_read_only(true);
  rocksdb_register_tx(hton, thd, tx);

  if (tx_isolation == ISO_REPEATABLE_READ) {
    tx->acquire_snapshot(true);
  } else {
    push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN, HA_ERR_UNSUPPORTED,
                        "Only REPEATABLE READ isolation level is supported "
                        "for START TRANSACTION WITH CONSISTENT SNAPSHOT "
                        "in RocksDB Storage Engine. Snapshot has not been "
                        "taken.");
  }  return HA_EXIT_SUCCESS;
}

/* Dummy SAVEPOINT support. This is needed for long running transactions
 * like mysqldump (https://bugs.mysql.com/bug.php?id=71017).
 * Current SAVEPOINT does not correctly handle ROLLBACK and does not return
 * errors. This needs to be addressed in future versions (Issue#96).
 */
static int rocksdb_savepoint(handlerton *const hton, THD *const thd,
                             void *const savepoint) {
  return HA_EXIT_SUCCESS;
}

static int rocksdb_rollback_to_savepoint(handlerton *const hton, THD *const thd,
                                         void *const savepoint) {
  Rdb_transaction *&tx = get_tx_from_thd(thd);
  return tx->rollback_to_savepoint(savepoint);
}

static bool
rocksdb_rollback_to_savepoint_can_release_mdl(handlerton *const hton,
                                              THD *const thd) {
  return true;
}

static rocksdb::Status check_rocksdb_options_compatibility(
  const char *const dbpath, const rocksdb::Options& main_opts,
  const std::vector<rocksdb::ColumnFamilyDescriptor>& cf_descr)
{
  DBUG_ASSERT(rocksdb_datadir != nullptr);

  rocksdb::DBOptions loaded_db_opt;
  std::vector<rocksdb::ColumnFamilyDescriptor> loaded_cf_descs;
  rocksdb::Status status = LoadLatestOptions(dbpath,
                                             rocksdb::Env::Default(),
                                             &loaded_db_opt, &loaded_cf_descs);

  // If we're starting from scratch and there are no options saved yet then this
  // is a valid case. Therefore we can't compare the current set of options to
  // anything.
  if (status.IsNotFound()) {
    return rocksdb::Status::OK();
  }

  if (!status.ok()) {
    return status;
  }

  if (loaded_cf_descs.size() != cf_descr.size()) {
    return rocksdb::Status::NotSupported("Mismatched size of column family "
                                         "descriptors.");
  }

  // Please see RocksDB documentation for more context about why we need to set
  // user-defined functions and pointer-typed options manually.
  for (size_t i = 0; i < loaded_cf_descs.size(); i++) {
    loaded_cf_descs[i].options.compaction_filter =
        cf_descr[i].options.compaction_filter;
    loaded_cf_descs[i].options.compaction_filter_factory =
        cf_descr[i].options.compaction_filter_factory;
    loaded_cf_descs[i].options.comparator = cf_descr[i].options.comparator;
    loaded_cf_descs[i].options.memtable_factory =
        cf_descr[i].options.memtable_factory;
    loaded_cf_descs[i].options.merge_operator =
        cf_descr[i].options.merge_operator;
    loaded_cf_descs[i].options.prefix_extractor =
        cf_descr[i].options.prefix_extractor;
    loaded_cf_descs[i].options.table_factory =
        cf_descr[i].options.table_factory;
  }

  // This is the essence of the function - determine if it's safe to open the
  // database or not.
  status = CheckOptionsCompatibility(dbpath, rocksdb::Env::Default(), main_opts,
                                     loaded_cf_descs);

  return status;
}

/*
  Storage Engine initialization function, invoked when plugin is loaded.
*/

static int rocksdb_init_func(void *const p) {
  DBUG_ENTER_FUNC();

  // Validate the assumption about the size of ROCKSDB_SIZEOF_HIDDEN_PK_COLUMN.
  static_assert(sizeof(longlong) == 8, "Assuming that longlong is 8 bytes.");

#ifdef HAVE_PSI_INTERFACE
  init_rocksdb_psi_keys();
#endif

  rocksdb_hton = (handlerton *)p;
  mysql_mutex_init(rdb_psi_open_tbls_mutex_key, &rdb_open_tables.m_mutex,
                   MY_MUTEX_INIT_FAST);
#ifdef HAVE_PSI_INTERFACE
  rdb_bg_thread.init(rdb_signal_bg_psi_mutex_key, rdb_signal_bg_psi_cond_key);
  rdb_drop_idx_thread.init(rdb_signal_drop_idx_psi_mutex_key,
                           rdb_signal_drop_idx_psi_cond_key);
#else
  rdb_bg_thread.init();
  rdb_drop_idx_thread.init();
#endif
  mysql_mutex_init(rdb_collation_data_mutex_key, &rdb_collation_data_mutex,
                   MY_MUTEX_INIT_FAST);
  mysql_mutex_init(rdb_mem_cmp_space_mutex_key, &rdb_mem_cmp_space_mutex,
                   MY_MUTEX_INIT_FAST);

#if defined(HAVE_PSI_INTERFACE)
  rdb_collation_exceptions = new Regex(key_rwlock_collation_exception_list);
#else
  rdb_collation_exceptions = new Regex();
#endif

  mysql_mutex_init(rdb_sysvars_psi_mutex_key, &rdb_sysvars_mutex,
                   MY_MUTEX_INIT_FAST);
  rdb_open_tables.init_hash();
  Rdb_transaction::init_mutex();

  rocksdb_hton->state = SHOW_OPTION_YES;
  rocksdb_hton->create = rocksdb_create_handler;
  rocksdb_hton->close_connection = rocksdb_close_connection;
  rocksdb_hton->prepare = rocksdb_prepare;
  rocksdb_hton->commit_by_xid = rocksdb_commit_by_xid;
  rocksdb_hton->rollback_by_xid = rocksdb_rollback_by_xid;
  rocksdb_hton->recover = rocksdb_recover;
  rocksdb_hton->commit = rocksdb_commit;
  rocksdb_hton->rollback = rocksdb_rollback;
  rocksdb_hton->db_type = DB_TYPE_ROCKSDB;
  rocksdb_hton->show_status = rocksdb_show_status;
  rocksdb_hton->start_consistent_snapshot =
      rocksdb_start_tx_and_assign_read_view;
  rocksdb_hton->savepoint_set = rocksdb_savepoint;
  rocksdb_hton->savepoint_rollback = rocksdb_rollback_to_savepoint;
  rocksdb_hton->savepoint_rollback_can_release_mdl =
      rocksdb_rollback_to_savepoint_can_release_mdl;
  rocksdb_hton->flush_logs = rocksdb_flush_wal;

  rocksdb_hton->flags = HTON_TEMPORARY_NOT_SUPPORTED |
                        HTON_SUPPORTS_EXTENDED_KEYS | HTON_CAN_RECREATE;

  DBUG_ASSERT(!mysqld_embedded);

  rocksdb_stats = rocksdb::CreateDBStatistics();
  rocksdb_db_options.statistics = rocksdb_stats;

  if (rocksdb_rate_limiter_bytes_per_sec != 0) {
    rocksdb_rate_limiter.reset(
        rocksdb::NewGenericRateLimiter(rocksdb_rate_limiter_bytes_per_sec));
    rocksdb_db_options.rate_limiter = rocksdb_rate_limiter;
  }

  std::shared_ptr<Rdb_logger> myrocks_logger = std::make_shared<Rdb_logger>();
  rocksdb::Status s = rocksdb::CreateLoggerFromOptions(
      rocksdb_datadir, rocksdb_db_options, &rocksdb_db_options.info_log);
  if (s.ok()) {
    myrocks_logger->SetRocksDBLogger(rocksdb_db_options.info_log);
  }

  rocksdb_db_options.info_log = myrocks_logger;
  myrocks_logger->SetInfoLogLevel(
      static_cast<rocksdb::InfoLogLevel>(rocksdb_info_log_level));
  rocksdb_db_options.wal_dir = rocksdb_wal_dir;

  rocksdb_db_options.wal_recovery_mode =
      static_cast<rocksdb::WALRecoveryMode>(rocksdb_wal_recovery_mode);

  rocksdb_db_options.access_hint_on_compaction_start =
      static_cast<rocksdb::Options::AccessHint>(
          rocksdb_access_hint_on_compaction_start);

  if (rocksdb_db_options.allow_mmap_reads &&
      rocksdb_db_options.use_direct_reads) {
    // allow_mmap_reads implies !use_direct_reads and RocksDB will not open if
    // mmap_reads and direct_reads are both on.   (NO_LINT_DEBUG)
    sql_print_error("RocksDB: Can't enable both use_direct_reads "
                    "and allow_mmap_reads\n");
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  if (rocksdb_db_options.allow_mmap_writes &&
      rocksdb_db_options.use_direct_writes) {
    // See above comment for allow_mmap_reads. (NO_LINT_DEBUG)
    sql_print_error("RocksDB: Can't enable both use_direct_writes "
                    "and allow_mmap_writes\n");
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  std::vector<std::string> cf_names;
  rocksdb::Status status;
  status = rocksdb::DB::ListColumnFamilies(rocksdb_db_options, rocksdb_datadir,
                                           &cf_names);
  if (!status.ok()) {
    /*
      When we start on an empty datadir, ListColumnFamilies returns IOError,
      and RocksDB doesn't provide any way to check what kind of error it was.
      Checking system errno happens to work right now.
    */
    if (status.IsIOError() && errno == ENOENT) {
      sql_print_information("RocksDB: Got ENOENT when listing column families");
      sql_print_information(
          "RocksDB:   assuming that we're creating a new database");
    } else {
      std::string err_text = status.ToString();
      sql_print_error("RocksDB: Error listing column families: %s",
                      err_text.c_str());
      rdb_open_tables.free_hash();
      DBUG_RETURN(HA_EXIT_FAILURE);
    }
  } else
    sql_print_information("RocksDB: %ld column families found",
                          cf_names.size());

  std::vector<rocksdb::ColumnFamilyDescriptor> cf_descr;
  std::vector<rocksdb::ColumnFamilyHandle *> cf_handles;

  rocksdb_tbl_options.index_type =
      (rocksdb::BlockBasedTableOptions::IndexType)rocksdb_index_type;

  if (!rocksdb_tbl_options.no_block_cache) {
    rocksdb_tbl_options.block_cache =
        rocksdb::NewLRUCache(rocksdb_block_cache_size);
  }
  // Using newer BlockBasedTable format version for better compression
  // and better memory allocation.
  // See:
  // https://github.com/facebook/rocksdb/commit/9ab5adfc59a621d12357580c94451d9f7320c2dd
  rocksdb_tbl_options.format_version = 2;

  if (rocksdb_collect_sst_properties) {
    properties_collector_factory =
        std::make_shared<Rdb_tbl_prop_coll_factory>(&ddl_manager);

    rocksdb_set_compaction_options(nullptr, nullptr, nullptr, nullptr);

    mysql_mutex_lock(&rdb_sysvars_mutex);

    DBUG_ASSERT(rocksdb_table_stats_sampling_pct <=
                RDB_TBL_STATS_SAMPLE_PCT_MAX);
    properties_collector_factory->SetTableStatsSamplingPct(
        rocksdb_table_stats_sampling_pct);

    mysql_mutex_unlock(&rdb_sysvars_mutex);
  }

  if (rocksdb_persistent_cache_size > 0) {
    std::shared_ptr<rocksdb::PersistentCache> pcache;
    rocksdb::NewPersistentCache(
        rocksdb::Env::Default(), std::string(rocksdb_persistent_cache_path),
        rocksdb_persistent_cache_size, myrocks_logger, true, &pcache);
    rocksdb_tbl_options.persistent_cache = pcache;
  } else if (strlen(rocksdb_persistent_cache_path)) {
    sql_print_error("RocksDB: Must specify rocksdb_persistent_cache_size");
    DBUG_RETURN(1);
  }

  if (!rocksdb_cf_options_map.init(
          rocksdb_tbl_options, properties_collector_factory,
          rocksdb_default_cf_options, rocksdb_override_cf_options)) {
    // NO_LINT_DEBUG
    sql_print_error("RocksDB: Failed to initialize CF options map.");
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  /*
    If there are no column families, we're creating the new database.
    Create one column family named "default".
  */
  if (cf_names.size() == 0)
    cf_names.push_back(DEFAULT_CF_NAME);

  std::vector<int> compaction_enabled_cf_indices;
  sql_print_information("RocksDB: Column Families at start:");
  for (size_t i = 0; i < cf_names.size(); ++i) {
    rocksdb::ColumnFamilyOptions opts;
    rocksdb_cf_options_map.get_cf_options(cf_names[i], &opts);

    sql_print_information("  cf=%s", cf_names[i].c_str());
    sql_print_information("    write_buffer_size=%ld", opts.write_buffer_size);
    sql_print_information("    target_file_size_base=%" PRIu64,
                          opts.target_file_size_base);

    /*
      Temporarily disable compactions to prevent a race condition where
      compaction starts before compaction filter is ready.
    */
    if (!opts.disable_auto_compactions) {
      compaction_enabled_cf_indices.push_back(i);
      opts.disable_auto_compactions = true;
    }
    cf_descr.push_back(rocksdb::ColumnFamilyDescriptor(cf_names[i], opts));
  }

  rocksdb::Options main_opts(rocksdb_db_options,
                             rocksdb_cf_options_map.get_defaults());

  main_opts.env->SetBackgroundThreads(main_opts.max_background_flushes,
                                      rocksdb::Env::Priority::HIGH);
  main_opts.env->SetBackgroundThreads(main_opts.max_background_compactions,
                                      rocksdb::Env::Priority::LOW);
  rocksdb::TransactionDBOptions tx_db_options;
  tx_db_options.transaction_lock_timeout = 2; // 2 seconds
  tx_db_options.custom_mutex_factory = std::make_shared<Rdb_mutex_factory>();

  status =
      check_rocksdb_options_compatibility(rocksdb_datadir, main_opts, cf_descr);

  // We won't start if we'll determine that there's a chance of data corruption
  // because of incompatible options.
  if (!status.ok()) {
    // NO_LINT_DEBUG
    sql_print_error("RocksDB: compatibility check against existing database "
                    "options failed. %s",
                    status.ToString().c_str());
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  status = rocksdb::TransactionDB::Open(
      main_opts, tx_db_options, rocksdb_datadir, cf_descr, &cf_handles, &rdb);

  if (!status.ok()) {
    std::string err_text = status.ToString();
    sql_print_error("RocksDB: Error opening instance: %s", err_text.c_str());
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }
  cf_manager.init(&rocksdb_cf_options_map, &cf_handles);

  if (dict_manager.init(rdb->GetBaseDB(), &cf_manager)) {
    // NO_LINT_DEBUG
    sql_print_error("RocksDB: Failed to initialize data dictionary.");
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  if (ddl_manager.init(&dict_manager, &cf_manager, rocksdb_validate_tables)) {
    // NO_LINT_DEBUG
    sql_print_error("RocksDB: Failed to initialize DDL manager.");
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  for (const auto &cf_handle : cf_manager.get_all_cf()) {
    uint flags;
    if (!dict_manager.get_cf_flags(cf_handle->GetID(), &flags)) {
      const std::unique_ptr<rocksdb::WriteBatch> wb = dict_manager.begin();
      rocksdb::WriteBatch *const batch = wb.get();
      dict_manager.add_cf_flags(batch, cf_handle->GetID(), 0);
      dict_manager.commit(batch);
    }
  }


  Rdb_sst_info::init(rdb);

  /*
    Enable auto compaction, things needed for compaction filter are finished
    initializing
  */
  std::vector<rocksdb::ColumnFamilyHandle *> compaction_enabled_cf_handles;
  compaction_enabled_cf_handles.reserve(compaction_enabled_cf_indices.size());
  for (const auto &index : compaction_enabled_cf_indices) {
    compaction_enabled_cf_handles.push_back(cf_handles[index]);
  }

  status = rdb->EnableAutoCompaction(compaction_enabled_cf_handles);

  if (!status.ok()) {
    const std::string err_text = status.ToString();
    // NO_LINT_DEBUG
    sql_print_error("RocksDB: Error enabling compaction: %s", err_text.c_str());
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  auto err = rdb_bg_thread.create_thread(BG_THREAD_NAME
#ifdef HAVE_PSI_INTERFACE
                                         ,
                                         rdb_background_psi_thread_key
#endif
                                         );
  if (err != 0) {
    sql_print_error("RocksDB: Couldn't start the background thread: (errno=%d)",
                    err);
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  err = rdb_drop_idx_thread.create_thread(INDEX_THREAD_NAME
#ifdef HAVE_PSI_INTERFACE
                                          ,
                                          rdb_drop_idx_psi_thread_key
#endif
                                          );
  if (err != 0) {
    sql_print_error("RocksDB: Couldn't start the drop index thread: (errno=%d)",
                    err);
    rdb_open_tables.free_hash();
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  rdb_set_collation_exception_list(rocksdb_strict_collation_exceptions);

  if (rocksdb_pause_background_work) {
    rdb->PauseBackgroundWork();
  }

  sql_print_information("RocksDB instance opened");
  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/*
  Storage Engine deinitialization function, invoked when plugin is unloaded.
*/

static int rocksdb_done_func(void *const p) {
  DBUG_ENTER_FUNC();

  int error = 0;

  // signal the drop index thread to stop
  rdb_drop_idx_thread.signal(true);

  // Flush all memtables for not lose data, even if WAL is disabled.
  rocksdb_flush_all_memtables();

  // Stop all rocksdb background work
  CancelAllBackgroundWork(rdb->GetBaseDB(), true);

  // Signal the background thread to stop and to persist all stats collected
  // from background flushes and compactions. This will add more keys to a new
  // memtable, but since the memtables were just flushed, it should not trigger
  // a flush that can stall due to background threads being stopped. As long
  // as these keys are stored in a WAL file, they can be retrieved on restart.
  rdb_bg_thread.signal(true);

  // Wait for the background thread to finish.
  auto err = rdb_bg_thread.join();
  if (err != 0) {
    // We'll log the message and continue because we're shutting down and
    // continuation is the optimal strategy.
    // NO_LINT_DEBUG
    sql_print_error("RocksDB: Couldn't stop the background thread: (errno=%d)",
                    err);
  }

  // Wait for the drop index thread to finish.
  err = rdb_drop_idx_thread.join();
  if (err != 0) {
    // NO_LINT_DEBUG
    sql_print_error("RocksDB: Couldn't stop the index thread: (errno=%d)", err);
  }

  if (rdb_open_tables.m_hash.records) {
    // Looks like we are getting unloaded and yet we have some open tables
    // left behind.
    error = 1;
  }

  rdb_open_tables.free_hash();
  mysql_mutex_destroy(&rdb_open_tables.m_mutex);
  mysql_mutex_destroy(&rdb_sysvars_mutex);

  delete rdb_collation_exceptions;
  mysql_mutex_destroy(&rdb_collation_data_mutex);
  mysql_mutex_destroy(&rdb_mem_cmp_space_mutex);

  Rdb_transaction::term_mutex();

  for (auto &it : rdb_collation_data) {
    delete it;
    it = nullptr;
  }

  ddl_manager.cleanup();
  dict_manager.cleanup();
  cf_manager.cleanup();

  delete rdb;
  rdb = nullptr;

// Disown the cache data since we're shutting down.
// This results in memory leaks but it improved the shutdown time.
// Don't disown when running under valgrind
#ifndef HAVE_purify
  if (rocksdb_tbl_options.block_cache) {
    rocksdb_tbl_options.block_cache->DisownData();
  }
#endif /* HAVE_purify */

  DBUG_RETURN(error);
}

/**
  @brief
  Example of simple lock controls. The "table_handler" it creates is a
  structure we will pass to each ha_rocksdb handler. Do you have to have
  one of these? Well, you have pieces that are used for locking, and
  they are needed to function.
*/

Rdb_table_handler *
Rdb_open_tables_map::get_table_handler(const char *const table_name) {
  Rdb_table_handler *table_handler;
  uint length;
  char *tmp_name;

  DBUG_ASSERT(table_name != nullptr);
  length = (uint)strlen(table_name);

  // First, look up the table in the hash map.
  mysql_mutex_lock(&m_mutex);
  if (!(table_handler = reinterpret_cast<Rdb_table_handler *>(my_hash_search(
            &m_hash, reinterpret_cast<const uchar *>(table_name), length)))) {
    // Since we did not find it in the hash map, attempt to create and add it
    // to the hash map.
    if (!(table_handler = reinterpret_cast<Rdb_table_handler *>(my_multi_malloc(
              MYF(MY_WME | MY_ZEROFILL), &table_handler, sizeof(*table_handler),
              &tmp_name, length + 1, NullS)))) {
      // Allocating a new Rdb_table_handler and a new table name failed.
      mysql_mutex_unlock(&m_mutex);
      return nullptr;
    }

    table_handler->m_ref_count = 0;
    table_handler->m_table_name_length = length;
    table_handler->m_table_name = tmp_name;
    strmov(table_handler->m_table_name, table_name);

    if (my_hash_insert(&m_hash, reinterpret_cast<uchar *>(table_handler))) {
      // Inserting into the hash map failed.
      mysql_mutex_unlock(&m_mutex);
      my_free(table_handler);
      return nullptr;
    }

    thr_lock_init(&table_handler->m_thr_lock);
    table_handler->m_io_perf_read.init();
  }
  DBUG_ASSERT(table_handler->m_ref_count >= 0);
  table_handler->m_ref_count++;

  mysql_mutex_unlock(&m_mutex);

  return table_handler;
}

std::vector<std::string> rdb_get_open_table_names(void) {
  return rdb_open_tables.get_table_names();
}

std::vector<std::string> Rdb_open_tables_map::get_table_names(void) const {
  ulong i;
  const Rdb_table_handler *table_handler;
  std::vector<std::string> names;

  mysql_mutex_lock(&m_mutex);
  for (i = 0; (table_handler = reinterpret_cast<const Rdb_table_handler *>(
                   my_hash_const_element(&m_hash, i)));
       i++) {
    DBUG_ASSERT(table_handler != nullptr);
    names.push_back(table_handler->m_table_name);
  }
  DBUG_ASSERT(i == m_hash.records);
  mysql_mutex_unlock(&m_mutex);

  return names;
}

void ha_rocksdb::load_auto_incr_value() {
  const int save_active_index = active_index;
  active_index = table->s->next_number_index;
  const uint8 save_table_status = table->status;

  /*
    load_auto_incr_value() may be called by statements that
    do not execute implicit commits (i.e. SHOW CREATE TABLE).
    index_last() creates a snapshot. When a snapshot is created
    here, it has to be released as well. (GitHub issue#189)
  */
  Rdb_transaction *const tx = get_or_create_tx(table->in_use);
  const bool is_new_snapshot = !tx->has_snapshot();

  // Do a lookup. We only need index column, so it should be index-only.
  // (another reason to make it index-only is that table->read_set is
  //  not set appropriately and non-index-only lookup will not read the value)
  const bool save_keyread_only = m_keyread_only;
  m_keyread_only = true;

  if (!index_last(table->record[0]))
    update_auto_incr_val();

  m_keyread_only = save_keyread_only;
  if (is_new_snapshot) {
    tx->release_snapshot();
  }

  table->status = save_table_status;
  active_index = save_active_index;

  /*
    Do what ha_rocksdb::index_end() does.
    (Why don't we use index_init/index_end? class handler defines index_init
     as private, for some reason).
  */
  release_scan_iterator();
}

/* Get PK value from table->record[0]. */
/*
  TODO(alexyang): No existing support for auto_increment on non-pk columns, see
  end of ha_rocksdb::create. Also see opened issue here:
  https://github.com/facebook/mysql-5.6/issues/153
*/
void ha_rocksdb::update_auto_incr_val() {
  Field *field;
  longlong new_val;
  field = table->key_info[table->s->next_number_index].key_part[0].field;

  my_bitmap_map *const old_map =
      dbug_tmp_use_all_columns(table, table->read_set);
  new_val = field->val_int() + 1;
  dbug_tmp_restore_column_map(table->read_set, old_map);

  longlong auto_incr_val = m_tbl_def->m_auto_incr_val;
  while (auto_incr_val < new_val &&
         !m_tbl_def->m_auto_incr_val.compare_exchange_weak(auto_incr_val,
                                                           new_val)) {
    // Do nothing - just loop until auto_incr_val is >= new_val or
    // we successfully set it
  }
}

int ha_rocksdb::load_hidden_pk_value() {
  const int save_active_index = active_index;
  active_index = m_tbl_def->m_key_count - 1;
  const uint8 save_table_status = table->status;

  Rdb_transaction *const tx = get_or_create_tx(table->in_use);
  const bool is_new_snapshot = !tx->has_snapshot();

  // Do a lookup.
  if (!index_last(table->record[0])) {
    /*
      Decode PK field from the key
    */
    longlong hidden_pk_id = 0;
    if (read_hidden_pk_id_from_rowkey(&hidden_pk_id)) {
      if (is_new_snapshot) {
        tx->release_snapshot();
      }
      return HA_ERR_INTERNAL_ERROR;
    }

    hidden_pk_id++;
    longlong old = m_tbl_def->m_hidden_pk_val;
    while (
        old < hidden_pk_id &&
        !m_tbl_def->m_hidden_pk_val.compare_exchange_weak(old, hidden_pk_id)) {
    }
  }

  if (is_new_snapshot) {
    tx->release_snapshot();
  }

  table->status = save_table_status;
  active_index = save_active_index;

  release_scan_iterator();

  return HA_EXIT_SUCCESS;
}

/* Get PK value from m_tbl_def->m_hidden_pk_info. */
longlong ha_rocksdb::update_hidden_pk_val() {
  DBUG_ASSERT(has_hidden_pk(table));
  const longlong new_val = m_tbl_def->m_hidden_pk_val++;
  return new_val;
}

/* Get the id of the hidden pk id from m_last_rowkey */
int ha_rocksdb::read_hidden_pk_id_from_rowkey(longlong *const hidden_pk_id) {
  DBUG_ASSERT(hidden_pk_id != nullptr);
  DBUG_ASSERT(table != nullptr);
  DBUG_ASSERT(has_hidden_pk(table));

  rocksdb::Slice rowkey_slice(m_last_rowkey.ptr(), m_last_rowkey.length());

  // Get hidden primary key from old key slice
  Rdb_string_reader reader(&rowkey_slice);
  if ((!reader.read(Rdb_key_def::INDEX_NUMBER_SIZE)))
    return HA_EXIT_FAILURE;

  const int length = Field_longlong::PACK_LENGTH;
  const uchar *from = reinterpret_cast<const uchar *>(reader.read(length));
  if (from == nullptr) {
    return HA_EXIT_FAILURE; /* Mem-comparable image doesn't have enough bytes */
  }

  *hidden_pk_id = rdb_netbuf_read_uint64(&from);
  return HA_EXIT_SUCCESS;
}

/**
  @brief
  Free lock controls. We call this whenever we close a table. If the table had
  the last reference to the table_handler, then we free the memory associated
  with it.
*/

void Rdb_open_tables_map::release_table_handler(
    Rdb_table_handler *const table_handler) {
  mysql_mutex_lock(&m_mutex);

  DBUG_ASSERT(table_handler != nullptr);
  DBUG_ASSERT(table_handler->m_ref_count > 0);
  if (!--table_handler->m_ref_count) {
    // Last rereference was released. Tear down the hash entry.
    const auto ret __attribute__((__unused__)) =
        my_hash_delete(&m_hash, reinterpret_cast<uchar *>(table_handler));
    DBUG_ASSERT(!ret); // the hash entry must actually be found and deleted
    my_core::thr_lock_delete(&table_handler->m_thr_lock);
    my_free(table_handler);
  }

  mysql_mutex_unlock(&m_mutex);
}

static handler *rocksdb_create_handler(my_core::handlerton *const hton,
                                       my_core::TABLE_SHARE *const table_arg,
                                       my_core::MEM_ROOT *const mem_root) {
  return new (mem_root) ha_rocksdb(hton, table_arg);
}

ha_rocksdb::ha_rocksdb(my_core::handlerton *const hton,
                       my_core::TABLE_SHARE *const table_arg)
    : handler(hton, table_arg), m_table_handler(nullptr), m_scan_it(nullptr),
      m_scan_it_skips_bloom(false), m_scan_it_snapshot(nullptr),
      m_tbl_def(nullptr), m_pk_descr(nullptr), m_key_descr_arr(nullptr),
      m_pk_can_be_decoded(false), m_maybe_unpack_info(false),
      m_pk_tuple(nullptr), m_pk_packed_tuple(nullptr),
      m_sk_packed_tuple(nullptr), m_end_key_packed_tuple(nullptr),
      m_sk_match_prefix(nullptr), m_sk_match_prefix_buf(nullptr),
      m_sk_packed_tuple_old(nullptr), m_dup_sk_packed_tuple(nullptr),
      m_dup_sk_packed_tuple_old(nullptr), m_pack_buffer(nullptr),
      m_lock_rows(RDB_LOCK_NONE), m_keyread_only(FALSE),
      m_bulk_load_tx(nullptr), m_encoder_arr(nullptr),
      m_row_checksums_checked(0), m_in_rpl_delete_rows(false),
      m_in_rpl_update_rows(false) {
  // TODO(alexyang): create a valid PSI_mutex_key for this mutex
  mysql_mutex_init(0, &m_bulk_load_mutex, MY_MUTEX_INIT_FAST);
}

static const char *ha_rocksdb_exts[] = {NullS};

const char **ha_rocksdb::bas_ext() const {
  DBUG_ENTER_FUNC();

  DBUG_RETURN(ha_rocksdb_exts);
}

bool ha_rocksdb::same_table(const ha_rocksdb &other) const {
  return m_tbl_def->base_tablename() == other.m_tbl_def->base_tablename();
}

bool ha_rocksdb::init_with_fields() {
  DBUG_ENTER_FUNC();

  const uint pk = table_share->primary_key;
  if (pk != MAX_KEY) {
    const uint key_parts = table_share->key_info[pk].user_defined_key_parts;
    check_keyread_allowed(pk /*PK*/, key_parts - 1, true);
  } else
    m_pk_can_be_decoded = false;

  cached_table_flags = table_flags();

  DBUG_RETURN(false); /* Ok */
}

/**
  Convert record from table->record[0] form into a form that can be written
  into rocksdb.

  @param pk_packed_slice      Packed PK tuple. We need it in order to compute
                              and store its CRC.
  @param packed_rec      OUT  Data slice with record data.
*/

void ha_rocksdb::convert_record_to_storage_format(
    const rocksdb::Slice &pk_packed_slice,
    Rdb_string_writer *const pk_unpack_info, rocksdb::Slice *const packed_rec) {
  m_storage_record.length(0);

  /* All NULL bits are initially 0 */
  m_storage_record.fill(m_null_bytes_in_rec, 0);

  // If a primary key may have non-empty unpack_info for certain values,
  // (m_maybe_unpack_info=TRUE), we write the unpack_info block. The block
  // itself was prepared in Rdb_key_def::pack_record.
  if (m_maybe_unpack_info) {
    m_storage_record.append(reinterpret_cast<char *>(pk_unpack_info->ptr()),
                            pk_unpack_info->get_current_pos());
  }

  for (uint i = 0; i < table->s->fields; i++) {
    /* Don't pack decodable PK key parts */
    if (m_encoder_arr[i].m_storage_type != Rdb_field_encoder::STORE_ALL) {
      continue;
    }

    Field *const field = table->field[i];
    if (m_encoder_arr[i].maybe_null()) {
      char *const data = (char *)m_storage_record.ptr();
      if (field->is_null()) {
        data[m_encoder_arr[i].m_null_offset] |= m_encoder_arr[i].m_null_mask;
        /* Don't write anything for NULL values */
        continue;
      }
    }

    if (m_encoder_arr[i].m_field_type == MYSQL_TYPE_BLOB) {
      my_core::Field_blob *blob = (my_core::Field_blob *)field;
      /* Get the number of bytes needed to store length*/
      const uint length_bytes = blob->pack_length() - portable_sizeof_char_ptr;

      /* Store the length of the value */
      m_storage_record.append(reinterpret_cast<char *>(blob->ptr),
                              length_bytes);

      /* Store the blob value itself */
      char *data_ptr;
      memcpy(&data_ptr, blob->ptr + length_bytes, sizeof(uchar **));
      m_storage_record.append(data_ptr, blob->get_length());
    } else if (m_encoder_arr[i].m_field_type == MYSQL_TYPE_VARCHAR) {
      Field_varstring *const field_var = (Field_varstring *)field;
      uint data_len;
      /* field_var->length_bytes is 1 or 2 */
      if (field_var->length_bytes == 1) {
        data_len = field_var->ptr[0];
      } else {
        DBUG_ASSERT(field_var->length_bytes == 2);
        data_len = uint2korr(field_var->ptr);
      }
      m_storage_record.append(reinterpret_cast<char *>(field_var->ptr),
                              field_var->length_bytes + data_len);
    } else {
      /* Copy the field data */
      const uint len = field->pack_length_in_rec();
      m_storage_record.append(reinterpret_cast<char *>(field->ptr), len);
    }
  }

  if (should_store_row_debug_checksums()) {
    const uint32_t key_crc32 = my_core::crc32(
        0, rdb_slice_to_uchar_ptr(&pk_packed_slice), pk_packed_slice.size());
    const uint32_t val_crc32 =
        my_core::crc32(0, rdb_mysql_str_to_uchar_str(&m_storage_record),
                       m_storage_record.length());
    uchar key_crc_buf[RDB_CHECKSUM_SIZE];
    uchar val_crc_buf[RDB_CHECKSUM_SIZE];
    rdb_netbuf_store_uint32(key_crc_buf, key_crc32);
    rdb_netbuf_store_uint32(val_crc_buf, val_crc32);
    m_storage_record.append((const char *)&RDB_CHECKSUM_DATA_TAG, 1);
    m_storage_record.append((const char *)key_crc_buf, RDB_CHECKSUM_SIZE);
    m_storage_record.append((const char *)val_crc_buf, RDB_CHECKSUM_SIZE);
  }

  *packed_rec =
      rocksdb::Slice(m_storage_record.ptr(), m_storage_record.length());
}

/*
  @brief
    Setup which fields will be unpacked when reading rows

  @detail
    Two special cases when we still unpack all fields:
    - When this table is being updated (m_lock_rows==RDB_LOCK_WRITE).
    - When @@rocksdb_verify_row_debug_checksums is ON (In this mode, we need to
  read all
      fields to find whether there is a row checksum at the end. We could skip
      the fields instead of decoding them, but currently we do decoding.)

  @seealso
    ha_rocksdb::setup_field_converters()
    ha_rocksdb::convert_record_from_storage_format()
*/
void ha_rocksdb::setup_read_decoders() {
  m_decoders_vect.clear();

  int last_useful = 0;
  int skip_size = 0;

  for (uint i = 0; i < table->s->fields; i++) {
    // We only need the decoder if the whole record is stored.
    if (m_encoder_arr[i].m_storage_type != Rdb_field_encoder::STORE_ALL) {
      continue;
    }

    if (m_lock_rows == RDB_LOCK_WRITE || m_verify_row_debug_checksums ||
        bitmap_is_set(table->read_set, table->field[i]->field_index)) {
      // We will need to decode this field
      m_decoders_vect.push_back({&m_encoder_arr[i], true, skip_size});
      last_useful = m_decoders_vect.size();
      skip_size = 0;
    } else {
      if (m_encoder_arr[i].uses_variable_len_encoding() ||
          m_encoder_arr[i].maybe_null()) {
        // For variable-length field, we need to read the data and skip it
        m_decoders_vect.push_back({&m_encoder_arr[i], false, skip_size});
        skip_size = 0;
      } else {
        // Fixed-width field can be skipped without looking at it.
        // Add appropriate skip_size to the next field.
        skip_size += m_encoder_arr[i].m_pack_length_in_rec;
      }
    }
  }

  // It could be that the last few elements are varchars that just do
  // skipping. Remove them.
  m_decoders_vect.erase(m_decoders_vect.begin() + last_useful,
                        m_decoders_vect.end());
}

#ifndef NDEBUG
void dbug_append_garbage_at_end(std::string &on_disk_rec) {
  on_disk_rec.append("abc");
}

void dbug_truncate_record(std::string &on_disk_rec) { on_disk_rec.resize(0); }

void dbug_modify_rec_varchar12(std::string &on_disk_rec) {
  std::string res;
  // The record is NULL-byte followed by VARCHAR(10).
  // Put the NULL-byte
  res.append("\0", 1);
  // Then, add a valid VARCHAR(12) value.
  res.append("\xC", 1);
  res.append("123456789ab", 12);

  on_disk_rec.assign(res);
}

void dbug_modify_key_varchar8(String &on_disk_rec) {
  std::string res;
  // The key starts with index number
  res.append(on_disk_rec.ptr(), Rdb_key_def::INDEX_NUMBER_SIZE);

  // Then, a mem-comparable form of a varchar(8) value.
  res.append("ABCDE\0\0\0\xFC", 9);
  on_disk_rec.length(0);
  on_disk_rec.append(res.data(), res.size());
}

void dbug_create_err_inplace_alter() {
  my_printf_error(ER_UNKNOWN_ERROR,
                  "Intentional failure in inplace alter occurred.", MYF(0));
}
#endif

int ha_rocksdb::convert_record_from_storage_format(
    const rocksdb::Slice *const key, uchar *const buf) {
  DBUG_EXECUTE_IF("myrocks_simulate_bad_row_read1",
                  dbug_append_garbage_at_end(m_retrieved_record););
  DBUG_EXECUTE_IF("myrocks_simulate_bad_row_read2",
                  dbug_truncate_record(m_retrieved_record););
  DBUG_EXECUTE_IF("myrocks_simulate_bad_row_read3",
                  dbug_modify_rec_varchar12(m_retrieved_record););

  const rocksdb::Slice retrieved_rec_slice(&m_retrieved_record.front(),
                                           m_retrieved_record.size());
  return convert_record_from_storage_format(key, &retrieved_rec_slice, buf);
}

/*
  @brief
  Unpack the record in this->m_retrieved_record and this->m_last_rowkey from
  storage format into buf (which can be table->record[0] or table->record[1]).

  @param  key   Table record's key in mem-comparable form.
  @param  buf   Store record in table->record[0] format here

  @detail
    If the table has blobs, the unpacked data in buf may keep pointers to the
    data in this->m_retrieved_record.

    The key is only needed to check its checksum value (the checksum is in
    m_retrieved_record).

  @seealso
    ha_rocksdb::setup_read_decoders()  Sets up data structures which tell which
    columns to decode.

  @return
    0      OK
    other  Error inpacking the data
*/

int ha_rocksdb::convert_record_from_storage_format(
    const rocksdb::Slice *const key, const rocksdb::Slice *const value,
    uchar *const buf) {
  DBUG_ASSERT(key != nullptr);
  DBUG_ASSERT(buf != nullptr);

  Rdb_string_reader reader(value);
  const my_ptrdiff_t ptr_diff = buf - table->record[0];

  /*
    Decode PK fields from the key
  */
  DBUG_EXECUTE_IF("myrocks_simulate_bad_pk_read1",
                  dbug_modify_key_varchar8(m_last_rowkey););

  const rocksdb::Slice rowkey_slice(m_last_rowkey.ptr(),
                                    m_last_rowkey.length());
  const char *unpack_info = nullptr;
  uint16 unpack_info_len = 0;
  rocksdb::Slice unpack_slice;

  /* Other fields are decoded from the value */
  const char *null_bytes = nullptr;
  if (m_null_bytes_in_rec && !(null_bytes = reader.read(m_null_bytes_in_rec))) {
    return HA_ERR_INTERNAL_ERROR;
  }

  if (m_maybe_unpack_info) {
    unpack_info = reader.read(RDB_UNPACK_HEADER_SIZE);

    if (!unpack_info || unpack_info[0] != RDB_UNPACK_DATA_TAG) {
      return HA_ERR_INTERNAL_ERROR;
    }

    unpack_info_len =
        rdb_netbuf_to_uint16(reinterpret_cast<const uchar *>(unpack_info + 1));
    unpack_slice = rocksdb::Slice(unpack_info, unpack_info_len);

    reader.read(unpack_info_len - RDB_UNPACK_HEADER_SIZE);
  }

  if (m_pk_descr->unpack_record(table, buf, &rowkey_slice,
                                unpack_info ? &unpack_slice : nullptr,
                                false /* verify_checksum */)) {
    return HA_ERR_INTERNAL_ERROR;
  }

  for (auto it = m_decoders_vect.begin(); it != m_decoders_vect.end(); it++) {
    const Rdb_field_encoder *const field_dec = it->m_field_enc;
    const bool decode = it->m_decode;
    const bool isNull =
        field_dec->maybe_null() &&
        ((null_bytes[field_dec->m_null_offset] & field_dec->m_null_mask) != 0);

    Field *const field = table->field[field_dec->m_field_index];

    /* Skip the bytes we need to skip */
    if (it->m_skip && !reader.read(it->m_skip))
      return HA_ERR_INTERNAL_ERROR;

    if (isNull) {
      if (decode) {
        /* This sets the NULL-bit of this record */
        field->set_null(ptr_diff);
        /*
          Besides that, set the field value to default value. CHECKSUM TABLE
          depends on this.
        */
        uint field_offset = field->ptr - table->record[0];
        memcpy(buf + field_offset, table->s->default_values + field_offset,
               field->pack_length());
      }
      continue;
    } else {
      if (decode)
        field->set_notnull(ptr_diff);
    }

    if (field_dec->m_field_type == MYSQL_TYPE_BLOB) {
      my_core::Field_blob *const blob = (my_core::Field_blob *)field;
      /* Get the number of bytes needed to store length*/
      const uint length_bytes = blob->pack_length() - portable_sizeof_char_ptr;

      blob->move_field_offset(ptr_diff);

      const char *data_len_str;
      if (!(data_len_str = reader.read(length_bytes))) {
        blob->move_field_offset(-ptr_diff);
        return HA_ERR_INTERNAL_ERROR;
      }

      memcpy(blob->ptr, data_len_str, length_bytes);

      const uint32 data_len = blob->get_length(
          (uchar *)data_len_str, length_bytes, table->s->db_low_byte_first);
      const char *blob_ptr;
      if (!(blob_ptr = reader.read(data_len))) {
        blob->move_field_offset(-ptr_diff);
        return HA_ERR_INTERNAL_ERROR;
      }

      if (decode) {
        // set 8-byte pointer to 0, like innodb does (relevant for 32-bit
        // platforms)
        memset(blob->ptr + length_bytes, 0, 8);
        memcpy(blob->ptr + length_bytes, &blob_ptr, sizeof(uchar **));
        blob->move_field_offset(-ptr_diff);
      }
    } else if (field_dec->m_field_type == MYSQL_TYPE_VARCHAR) {
      Field_varstring *const field_var = (Field_varstring *)field;
      const char *data_len_str;
      if (!(data_len_str = reader.read(field_var->length_bytes)))
        return HA_ERR_INTERNAL_ERROR;

      uint data_len;
      /* field_var->length_bytes is 1 or 2 */
      if (field_var->length_bytes == 1) {
        data_len = (uchar)data_len_str[0];
      } else {
        DBUG_ASSERT(field_var->length_bytes == 2);
        data_len = uint2korr(data_len_str);
      }
      if (data_len > field->field_length) {
        /* The data on disk is longer than table DDL allows? */
        return HA_ERR_INTERNAL_ERROR;
      }
      if (!reader.read(data_len))
        return HA_ERR_INTERNAL_ERROR;

      if (decode) {
        memcpy(field_var->ptr + ptr_diff, data_len_str,
               field_var->length_bytes + data_len);
      }
    } else {
      const char *data_bytes;
      const uint len = field_dec->m_pack_length_in_rec;
      if (len > 0) {
        if ((data_bytes = reader.read(len)) == nullptr) {
          return HA_ERR_INTERNAL_ERROR;
        }
        if (decode)
          memcpy(field->ptr + ptr_diff, data_bytes, len);
      }
    }
  }

  if (m_verify_row_debug_checksums) {
    if (reader.remaining_bytes() == RDB_CHECKSUM_CHUNK_SIZE &&
        reader.read(1)[0] == RDB_CHECKSUM_DATA_TAG) {
      uint32_t stored_key_chksum =
          rdb_netbuf_to_uint32((const uchar *)reader.read(RDB_CHECKSUM_SIZE));
      uint32_t stored_val_chksum =
          rdb_netbuf_to_uint32((const uchar *)reader.read(RDB_CHECKSUM_SIZE));

      const uint32_t computed_key_chksum =
          my_core::crc32(0, rdb_slice_to_uchar_ptr(key), key->size());
      const uint32_t computed_val_chksum =
          my_core::crc32(0, rdb_slice_to_uchar_ptr(value),
                         value->size() - RDB_CHECKSUM_CHUNK_SIZE);

      DBUG_EXECUTE_IF("myrocks_simulate_bad_pk_checksum1",
                      stored_key_chksum++;);

      if (stored_key_chksum != computed_key_chksum) {
        m_pk_descr->report_checksum_mismatch(true, key->data(), key->size());
        return HA_ERR_INTERNAL_ERROR;
      }

      DBUG_EXECUTE_IF("myrocks_simulate_bad_pk_checksum2",
                      stored_val_chksum++;);
      if (stored_val_chksum != computed_val_chksum) {
        m_pk_descr->report_checksum_mismatch(false, value->data(),
                                             value->size());
        return HA_ERR_INTERNAL_ERROR;
      }

      m_row_checksums_checked++;
    }
    if (reader.remaining_bytes())
      return HA_ERR_INTERNAL_ERROR;
  }

  return HA_EXIT_SUCCESS;
}

void ha_rocksdb::get_storage_type(Rdb_field_encoder *const encoder,
                                  const uint &kp) {
  // STORE_SOME uses unpack_info.
  if (m_pk_descr->has_unpack_info(kp)) {
    DBUG_ASSERT(m_pk_descr->can_unpack(kp));
    encoder->m_storage_type = Rdb_field_encoder::STORE_SOME;
    m_maybe_unpack_info = true;
  } else if (m_pk_descr->can_unpack(kp)) {
    encoder->m_storage_type = Rdb_field_encoder::STORE_NONE;
  }
}

/*
  Setup data needed to convert table->record[] to and from record storage
  format.

  @seealso
     ha_rocksdb::convert_record_to_storage_format,
     ha_rocksdb::convert_record_from_storage_format
*/

void ha_rocksdb::setup_field_converters() {
  uint i;
  uint null_bytes = 0;
  uchar cur_null_mask = 0x1;

  DBUG_ASSERT(m_encoder_arr == nullptr);
  m_encoder_arr = static_cast<Rdb_field_encoder *>(
      my_malloc(table->s->fields * sizeof(Rdb_field_encoder), MYF(0)));
  if (m_encoder_arr == nullptr) {
    return;
  }

  for (i = 0; i < table->s->fields; i++) {
    Field *const field = table->field[i];
    m_encoder_arr[i].m_storage_type = Rdb_field_encoder::STORE_ALL;

    /*
      Check if this field is
      - a part of primary key, and
      - it can be decoded back from its key image.
      If both hold, we don't need to store this field in the value part of
      RocksDB's key-value pair.

      If hidden pk exists, we skip this check since the field will never be
      part of the hidden pk.
    */
    if (!has_hidden_pk(table) &&
        field->part_of_key.is_set(table->s->primary_key)) {
      KEY *const pk_info = &table->key_info[table->s->primary_key];
      for (uint kp = 0; kp < pk_info->user_defined_key_parts; kp++) {
        /* key_part->fieldnr is counted from 1 */
        if (field->field_index + 1 == pk_info->key_part[kp].fieldnr) {
          get_storage_type(&m_encoder_arr[i], kp);
          break;
        }
      }
    }

    m_encoder_arr[i].m_field_type = field->real_type();
    m_encoder_arr[i].m_field_index = i;
    m_encoder_arr[i].m_pack_length_in_rec = field->pack_length_in_rec();

    if (field->real_maybe_null()) {
      m_encoder_arr[i].m_null_mask = cur_null_mask;
      m_encoder_arr[i].m_null_offset = null_bytes;
      if (cur_null_mask == 0x80) {
        cur_null_mask = 0x1;
        null_bytes++;
      } else
        cur_null_mask = cur_null_mask << 1;
    } else {
      m_encoder_arr[i].m_null_mask = 0;
    }
  }

  /* Count the last, unfinished NULL-bits byte */
  if (cur_null_mask != 0x1)
    null_bytes++;

  m_null_bytes_in_rec = null_bytes;
}

int ha_rocksdb::alloc_key_buffers(const TABLE *const table_arg,
                                  const Rdb_tbl_def *const tbl_def_arg,
                                  bool alloc_alter_buffers) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(m_pk_tuple == nullptr);
  DBUG_ASSERT(tbl_def_arg != nullptr);

  std::shared_ptr<Rdb_key_def> *const kd_arr = tbl_def_arg->m_key_descr_arr;

  uint key_len = 0;
  uint max_packed_sk_len = 0;
  uint pack_key_len = 0;

  m_pk_descr = kd_arr[pk_index(table_arg, tbl_def_arg)];
  if (has_hidden_pk(table_arg)) {
    m_pk_key_parts = 1;
  } else {
    m_pk_key_parts =
        table->key_info[table->s->primary_key].user_defined_key_parts;
    key_len = table->key_info[table->s->primary_key].key_length;
  }

  // move this into get_table_handler() ??
  m_pk_descr->setup(table_arg, tbl_def_arg);

  m_pk_tuple = reinterpret_cast<uchar *>(my_malloc(key_len, MYF(0)));
  if (m_pk_tuple == nullptr) {
    goto error;
  }

  pack_key_len = m_pk_descr->max_storage_fmt_length();
  m_pk_packed_tuple =
      reinterpret_cast<uchar *>(my_malloc(pack_key_len, MYF(0)));
  if (m_pk_packed_tuple == nullptr) {
    goto error;
  }

  /* Sometimes, we may use m_sk_packed_tuple for storing packed PK */
  max_packed_sk_len = pack_key_len;
  for (uint i = 0; i < table_arg->s->keys; i++) {
    if (i == table_arg->s->primary_key) /* Primary key was processed above */
      continue;

    // TODO: move this into get_table_handler() ??
    kd_arr[i]->setup(table_arg, tbl_def_arg);

    const uint packed_len = kd_arr[i]->max_storage_fmt_length();
    if (packed_len > max_packed_sk_len) {
      max_packed_sk_len = packed_len;
    }
  }

  if (!(m_sk_packed_tuple =
            reinterpret_cast<uchar *>(my_malloc(max_packed_sk_len, MYF(0)))) ||
      !(m_sk_match_prefix_buf =
            reinterpret_cast<uchar *>(my_malloc(max_packed_sk_len, MYF(0)))) ||
      !(m_sk_packed_tuple_old =
            reinterpret_cast<uchar *>(my_malloc(max_packed_sk_len, MYF(0)))) ||
      !(m_end_key_packed_tuple =
            reinterpret_cast<uchar *>(my_malloc(max_packed_sk_len, MYF(0)))) ||
      !((m_pack_buffer = reinterpret_cast<uchar *>(
             my_malloc(max_packed_sk_len, MYF(0)))))) {
    goto error;
  }

  /*
    If inplace alter is happening, allocate special buffers for unique
    secondary index duplicate checking.
  */
  if (alloc_alter_buffers &&
      (!(m_dup_sk_packed_tuple =
             reinterpret_cast<uchar *>(my_malloc(max_packed_sk_len, MYF(0)))) ||
       !(m_dup_sk_packed_tuple_old = reinterpret_cast<uchar *>(
             my_malloc(max_packed_sk_len, MYF(0)))))) {
    goto error;
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);

error:
  // If we're here then this means that at some point above an allocation may
  // have failed. To avoid any resource leaks and maintain a clear contract
  // we'll clean up before returning the error code.
  free_key_buffers();

  DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
}

void ha_rocksdb::free_key_buffers() {
  my_free(m_pk_tuple);
  m_pk_tuple = nullptr;

  my_free(m_pk_packed_tuple);
  m_pk_packed_tuple = nullptr;

  my_free(m_sk_packed_tuple);
  m_sk_packed_tuple = nullptr;

  my_free(m_sk_match_prefix_buf);
  m_sk_match_prefix_buf = nullptr;

  my_free(m_sk_packed_tuple_old);
  m_sk_packed_tuple_old = nullptr;

  my_free(m_end_key_packed_tuple);
  m_end_key_packed_tuple = nullptr;

  my_free(m_pack_buffer);
  m_pack_buffer = nullptr;

  my_free(m_dup_sk_packed_tuple);
  m_dup_sk_packed_tuple = nullptr;

  my_free(m_dup_sk_packed_tuple_old);
  m_dup_sk_packed_tuple_old = nullptr;
}

void ha_rocksdb::set_use_read_free_rpl(const char *const whitelist) {
  DBUG_ASSERT(whitelist != nullptr);

#if defined(HAVE_PSI_INTERFACE)
  Regex regex_handler(key_rwlock_read_free_rpl_tables);
#else
  Regex regex_handler;
#endif

  int flags = MY_REG_EXTENDED | MY_REG_NOSUB;
  if (lower_case_table_names)
    flags |= MY_REG_ICASE;

  if (!regex_handler.compile(whitelist,
                             flags,
                             table_alias_charset)) {
      warn_about_bad_patterns(regex_handler, "read_free_rpl_tables");
  }

  m_use_read_free_rpl = regex_handler.match(m_tbl_def->base_tablename());
}

int ha_rocksdb::open(const char *const name, int mode, uint test_if_locked) {
  DBUG_ENTER_FUNC();

  if (close()) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  m_table_handler = rdb_open_tables.get_table_handler(name);

  if (m_table_handler == nullptr) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  my_core::thr_lock_data_init(&m_table_handler->m_thr_lock, &m_db_lock,
                              nullptr);
  m_io_perf.init(&m_table_handler->m_table_perf_context,
                 &m_table_handler->m_io_perf_read, &stats);

  std::string fullname;
  if (rdb_normalize_tablename(name, &fullname)) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  m_tbl_def = ddl_manager.find(fullname);
  if (m_tbl_def == nullptr) {
    my_error(ER_INTERNAL_ERROR, MYF(0),
             "Attempt to open a table that is not present in RocksDB-SE data "
             "dictionary");
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }
  m_lock_rows = RDB_LOCK_NONE;

  m_key_descr_arr = m_tbl_def->m_key_descr_arr;

  /*
    Full table scan actually uses primary key
    (UPDATE needs to know this, otherwise it will go into infinite loop on
    queries like "UPDATE tbl SET pk=pk+100")
  */
  key_used_on_scan = table->s->primary_key;

  // close() above has already called free_key_buffers(). No need to do it here.
  int err = alloc_key_buffers(table, m_tbl_def);

  if (err) {
    DBUG_RETURN(err);
  }

  /*
    init_with_fields() is used to initialize table flags based on the field
    definitions in table->field[].
    It is called by open_binary_frm(), but that function calls the method for
    a temporary ha_rocksdb object which is later destroyed.

    If we are here in ::open(), then init_with_fields() has not been called
    for this object. Call it ourselves, we want all member variables to be
    properly initialized.
  */
  init_with_fields();

  setup_field_converters();

  info(HA_STATUS_NO_LOCK | HA_STATUS_VARIABLE | HA_STATUS_CONST);

  /*
    The following load_XXX code calls row decode functions, and they do
    that without having done ::external_lock() or index_init()/rnd_init().
    (Note: this also means we're doing a read when there was no
    setup_field_converters() call)

    Initialize the necessary variables for them:
  */
  m_verify_row_debug_checksums = false;

  /* TODO: move the following to where TABLE_SHARE is opened: */
  if (table->found_next_number_field)
    load_auto_incr_value();

  if (has_hidden_pk(table) && load_hidden_pk_value()) {
    free_key_buffers();
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  /* Index block size in MyRocks: used by MySQL in query optimization */
  stats.block_size = rocksdb_tbl_options.block_size;

  /* Determine at open whether we can use Read Free Replication or not */
  set_use_read_free_rpl(THDVAR(ha_thd(), read_free_rpl_tables));

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

int ha_rocksdb::close(void) {
  DBUG_ENTER_FUNC();

  m_pk_descr = nullptr;
  m_key_descr_arr = nullptr;

  free_key_buffers();

  my_free(m_encoder_arr);
  m_encoder_arr = nullptr;

  if (m_table_handler != nullptr) {
    rdb_open_tables.release_table_handler(m_table_handler);
    m_table_handler = nullptr;
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

bool ha_rocksdb::get_error_message(const int error, String *const buf) {
  DBUG_ENTER_FUNC();

  static_assert(HA_ERR_ROCKSDB_LAST > HA_ERR_FIRST,
                "HA_ERR_ROCKSDB_LAST > HA_ERR_FIRST");
  static_assert(HA_ERR_ROCKSDB_LAST > HA_ERR_LAST,
                "HA_ERR_ROCKSDB_LAST > HA_ERR_LAST");

  DBUG_ASSERT(error > 0);
  DBUG_ASSERT(error <= HA_ERR_ROCKSDB_LAST);
  DBUG_ASSERT(buf != nullptr);

  switch (error) {
  case HA_ERR_ROCKSDB_PK_REQUIRED:
    buf->append("Table must have a PRIMARY KEY.");
    break;
  case HA_ERR_ROCKSDB_UNIQUE_NOT_SUPPORTED:
    buf->append("Unique indexes are not supported.");
    break;
  case HA_ERR_ROCKSDB_TOO_MANY_LOCKS:
    buf->append("Number of locks held reached @@rocksdb_max_row_locks.");
    break;
  default:
    // We can be called with the values which are < HA_ERR_FIRST because most
    // MySQL internal functions will just return HA_EXIT_FAILURE in case of
    // an error.
    break;
  }

  DBUG_RETURN(false);
}

/* MyRocks supports only the following collations for indexed columns */
static const std::set<const my_core::CHARSET_INFO *> RDB_INDEX_COLLATIONS = {
    &my_charset_bin, &my_charset_utf8_bin, &my_charset_latin1_bin};

static bool
rdb_is_index_collation_supported(const my_core::Field *const field) {
  const my_core::enum_field_types type = field->real_type();
  /* Handle [VAR](CHAR|BINARY) or TEXT|BLOB */
  if (type == MYSQL_TYPE_VARCHAR || type == MYSQL_TYPE_STRING ||
      type == MYSQL_TYPE_BLOB) {
    return RDB_INDEX_COLLATIONS.find(field->charset()) !=
           RDB_INDEX_COLLATIONS.end();
  }
  return true;
}

/*
  Create structures needed for storing data in rocksdb. This is called when the
  table is created. The structures will be shared by all TABLE* objects.

  @param
    table_arg        Table with definition
    db_table         "dbname.tablename"
    len              strlen of the above
    tbl_def_arg      tbl_def whose key_descr is being created/populated
    old_tbl_def_arg  tbl_def from which keys are being copied over from
                     (for use during inplace alter)

  @return
    0      - Ok
    other  - error, either given table ddl is not supported by rocksdb or OOM.
*/
int ha_rocksdb::create_key_defs(
    const TABLE *const table_arg, Rdb_tbl_def *const tbl_def_arg,
    const TABLE *const old_table_arg /* = nullptr */,
    const Rdb_tbl_def *const old_tbl_def_arg
    /* = nullptr */) const {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(table_arg != nullptr);
  DBUG_ASSERT(table_arg->s != nullptr);

  uint i;

  /*
    These need to be one greater than MAX_INDEXES since the user can create
    MAX_INDEXES secondary keys and no primary key which would cause us
    to generate a hidden one.
  */
  std::array<key_def_cf_info, MAX_INDEXES + 1> cfs;

  /*
    NOTE: All new column families must be created before new index numbers are
    allocated to each key definition. See below for more details.
    http://github.com/MySQLOnRocksDB/mysql-5.6/issues/86#issuecomment-138515501
  */
  if (create_cfs(table_arg, tbl_def_arg, &cfs)) {
    DBUG_RETURN(HA_EXIT_FAILURE);
  };

  if (!old_tbl_def_arg) {
    /*
      old_tbl_def doesn't exist. this means we are in the process of creating
      a new table.

      Get the index numbers (this will update the next_index_number)
      and create Rdb_key_def structures.
    */
    for (i = 0; i < tbl_def_arg->m_key_count; i++) {
      if (create_key_def(table_arg, i, tbl_def_arg, &m_key_descr_arr[i],
                         cfs[i])) {
        DBUG_RETURN(HA_EXIT_FAILURE);
      }
    }
  } else {
    /*
      old_tbl_def exists.  This means we are creating a new tbl_def as part of
      in-place alter table.  Copy over existing keys from the old_tbl_def and
      generate the necessary new key definitions if any.
    */
    if (create_inplace_key_defs(table_arg, tbl_def_arg, old_table_arg,
                                old_tbl_def_arg, cfs)) {
      DBUG_RETURN(HA_EXIT_FAILURE);
    }
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/*
  Checks index parameters and creates column families needed for storing data
  in rocksdb if necessary.

  @param in
    table_arg     Table with definition
    db_table      Table name
    tbl_def_arg   Table def structure being populated

  @param out
    cfs           CF info for each key definition in 'key_info' order

  @return
    0      - Ok
    other  - error
*/
int ha_rocksdb::create_cfs(
    const TABLE *const table_arg, Rdb_tbl_def *const tbl_def_arg,
    std::array<struct key_def_cf_info, MAX_INDEXES + 1> *const cfs) const {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(table_arg != nullptr);
  DBUG_ASSERT(table_arg->s != nullptr);

  char tablename_sys[NAME_LEN + 1];

  my_core::filename_to_tablename(tbl_def_arg->base_tablename().c_str(),
                                 tablename_sys, sizeof(tablename_sys));

  /*
    The first loop checks the index parameters and creates
    column families if necessary.
  */
  for (uint i = 0; i < tbl_def_arg->m_key_count; i++) {
    rocksdb::ColumnFamilyHandle *cf_handle;

    if (rocksdb_strict_collation_check &&
        !is_hidden_pk(i, table_arg, tbl_def_arg) &&
        tbl_def_arg->base_tablename().find(tmp_file_prefix) != 0) {
      for (uint part = 0; part < table_arg->key_info[i].actual_key_parts;
           part++) {
        if (!rdb_is_index_collation_supported(
                table_arg->key_info[i].key_part[part].field) &&
            !rdb_collation_exceptions->match(tablename_sys)) {
          std::string collation_err;
          for (const auto &coll : RDB_INDEX_COLLATIONS) {
            if (collation_err != "") {
              collation_err += ", ";
            }
            collation_err += coll->name;
          }
          my_printf_error(
              ER_UNKNOWN_ERROR, "Unsupported collation on string indexed "
                                "column %s.%s Use binary collation (%s).",
              MYF(0), tbl_def_arg->full_tablename().c_str(),
              table_arg->key_info[i].key_part[part].field->field_name,
              collation_err.c_str());
          DBUG_RETURN(HA_EXIT_FAILURE);
        }
      }
    }

    /*
      index comment has Column Family name. If there was no comment, we get
      NULL, and it means use the default column family.
    */
    const char *const comment = get_key_comment(i, table_arg, tbl_def_arg);
    const char *const key_name = get_key_name(i, table_arg, tbl_def_arg);

    if (looks_like_per_index_cf_typo(comment)) {
      my_error(ER_NOT_SUPPORTED_YET, MYF(0),
               "column family name looks like a typo of $per_index_cf");
      DBUG_RETURN(HA_EXIT_FAILURE);
    }
    /* Prevent create from using the system column family */
    if (comment && strcmp(DEFAULT_SYSTEM_CF_NAME, comment) == 0) {
      my_error(ER_WRONG_ARGUMENTS, MYF(0),
               "column family not valid for storing index data");
      DBUG_RETURN(HA_EXIT_FAILURE);
    }
    bool is_auto_cf_flag;
    cf_handle =
        cf_manager.get_or_create_cf(rdb, comment, tbl_def_arg->full_tablename(),
                                    key_name, &is_auto_cf_flag);
    if (!cf_handle)
      DBUG_RETURN(HA_EXIT_FAILURE);

    auto &cf = (*cfs)[i];
    cf.cf_handle = cf_handle;
    cf.is_reverse_cf = Rdb_cf_manager::is_cf_name_reverse(comment);
    cf.is_auto_cf = is_auto_cf_flag;
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/*
  Create key definition needed for storing data in rocksdb during ADD index
  inplace operations.

  @param in
    table_arg         Table with definition
    tbl_def_arg       New table def structure being populated
    old_tbl_def_arg   Old(current) table def structure
    cfs               Struct array which contains column family information

  @return
    0      - Ok
    other  - error, either given table ddl is not supported by rocksdb or OOM.
*/
int ha_rocksdb::create_inplace_key_defs(
    const TABLE *const table_arg, Rdb_tbl_def *const tbl_def_arg,
    const TABLE *const old_table_arg, const Rdb_tbl_def *const old_tbl_def_arg,
    const std::array<key_def_cf_info, MAX_INDEXES + 1> &cfs) const {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(table_arg != nullptr);
  DBUG_ASSERT(tbl_def_arg != nullptr);
  DBUG_ASSERT(old_tbl_def_arg != nullptr);

  std::shared_ptr<Rdb_key_def> *const old_key_descr =
      old_tbl_def_arg->m_key_descr_arr;
  std::shared_ptr<Rdb_key_def> *const new_key_descr =
      tbl_def_arg->m_key_descr_arr;
  const std::unordered_map<std::string, uint> old_key_pos =
      get_old_key_positions(table_arg, tbl_def_arg, old_table_arg,
                            old_tbl_def_arg);

  uint i;
  for (i = 0; i < tbl_def_arg->m_key_count; i++) {
    const auto &it = old_key_pos.find(get_key_name(i, table_arg, tbl_def_arg));
    if (it != old_key_pos.end()) {
      /*
        Found matching index in old table definition, so copy it over to the
        new one created.
      */
      const Rdb_key_def &okd = *old_key_descr[it->second];

      uint16 index_dict_version = 0;
      uchar index_type = 0;
      uint16 kv_version = 0;
      const GL_INDEX_ID gl_index_id = okd.get_gl_index_id();
      if (!dict_manager.get_index_info(gl_index_id, &index_dict_version,
                                       &index_type, &kv_version)) {
        // NO_LINT_DEBUG
        sql_print_error("RocksDB: Could not get index information "
                        "for Index Number (%u,%u), table %s",
                        gl_index_id.cf_id, gl_index_id.index_id,
                        old_tbl_def_arg->full_tablename().c_str());
        DBUG_RETURN(HA_EXIT_FAILURE);
      }

      /*
        We can't use the copy constructor because we need to update the
        keynr within the pack_info for each field and the keyno of the keydef
        itself.
      */
      new_key_descr[i] = std::make_shared<Rdb_key_def>(
          okd.get_index_number(), i, okd.get_cf(), index_dict_version,
          index_type, kv_version, okd.m_is_reverse_cf, okd.m_is_auto_cf,
          okd.m_name.c_str(), dict_manager.get_stats(gl_index_id));
    } else if (create_key_def(table_arg, i, tbl_def_arg, &new_key_descr[i],
                              cfs[i])) {
      DBUG_RETURN(HA_EXIT_FAILURE);
    }

    DBUG_ASSERT(new_key_descr[i] != nullptr);
    new_key_descr[i]->setup(table_arg, tbl_def_arg);
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

std::unordered_map<std::string, uint> ha_rocksdb::get_old_key_positions(
    const TABLE *const table_arg, const Rdb_tbl_def *const tbl_def_arg,
    const TABLE *const old_table_arg,
    const Rdb_tbl_def *const old_tbl_def_arg) const {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(table_arg != nullptr);
  DBUG_ASSERT(old_table_arg != nullptr);
  DBUG_ASSERT(tbl_def_arg != nullptr);
  DBUG_ASSERT(old_tbl_def_arg != nullptr);

  std::shared_ptr<Rdb_key_def> *const old_key_descr =
      old_tbl_def_arg->m_key_descr_arr;
  std::unordered_map<std::string, uint> old_key_pos;
  std::unordered_map<std::string, uint> new_key_pos;
  uint i;

  for (i = 0; i < tbl_def_arg->m_key_count; i++) {
    new_key_pos[get_key_name(i, table_arg, tbl_def_arg)] = i;
  }

  for (i = 0; i < old_tbl_def_arg->m_key_count; i++) {
    if (is_hidden_pk(i, old_table_arg, old_tbl_def_arg)) {
      old_key_pos[old_key_descr[i]->m_name] = i;
      continue;
    }

    /*
      In case of matching key name, need to check key parts of keys as well,
      in case a simultaneous drop + add is performed, where the key name is the
      same but the key parts are different.

      Example:
      CREATE TABLE t1 (a INT, b INT, KEY ka(a)) ENGINE=RocksDB;
      ALTER TABLE t1 DROP INDEX ka, ADD INDEX ka(b), ALGORITHM=INPLACE;
    */
    const KEY *const old_key = &old_table_arg->key_info[i];
    const auto &it = new_key_pos.find(old_key->name);
    if (it == new_key_pos.end()) {
      continue;
    }

    KEY *const new_key = &table_arg->key_info[it->second];

    if (!compare_key_parts(old_key, new_key)) {
      old_key_pos[old_key->name] = i;
    }
  }

  DBUG_RETURN(old_key_pos);
}

/* Check two keys to ensure that key parts within keys match */
int ha_rocksdb::compare_key_parts(const KEY *const old_key,
                                  const KEY *const new_key) const {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(old_key != nullptr);
  DBUG_ASSERT(new_key != nullptr);

  /* Skip if key parts do not match, as it is a different key */
  if (new_key->user_defined_key_parts != old_key->user_defined_key_parts) {
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  /* Check to see that key parts themselves match */
  for (uint i = 0; i < old_key->user_defined_key_parts; i++) {
    if (strcmp(old_key->key_part[i].field->field_name,
               new_key->key_part[i].field->field_name) != 0) {
      DBUG_RETURN(HA_EXIT_FAILURE);
    }
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/*
  Create key definition needed for storing data in rocksdb.
  This can be called either during CREATE table or doing ADD index operations.

  @param in
    table_arg     Table with definition
    i             Position of index being created inside table_arg->key_info
    tbl_def_arg   Table def structure being populated
    cf_info       Struct which contains column family information

  @param out
    new_key_def  Newly created index definition.

  @return
    0      - Ok
    other  - error, either given table ddl is not supported by rocksdb or OOM.
*/
int ha_rocksdb::create_key_def(const TABLE *const table_arg, const uint &i,
                               const Rdb_tbl_def *const tbl_def_arg,
                               std::shared_ptr<Rdb_key_def> *const new_key_def,
                               const struct key_def_cf_info &cf_info) const {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(new_key_def != nullptr);
  DBUG_ASSERT(*new_key_def == nullptr);

  const uint index_id = ddl_manager.get_and_update_next_number(&dict_manager);
  const uint16_t index_dict_version = Rdb_key_def::INDEX_INFO_VERSION_LATEST;
  uchar index_type;
  uint16_t kv_version;

  if (is_hidden_pk(i, table_arg, tbl_def_arg)) {
    index_type = Rdb_key_def::INDEX_TYPE_HIDDEN_PRIMARY;
    kv_version = Rdb_key_def::PRIMARY_FORMAT_VERSION_LATEST;
  } else if (i == table_arg->s->primary_key) {
    index_type = Rdb_key_def::INDEX_TYPE_PRIMARY;
    uint16 pk_latest_version = Rdb_key_def::PRIMARY_FORMAT_VERSION_LATEST;
    kv_version = pk_latest_version;
  } else {
    index_type = Rdb_key_def::INDEX_TYPE_SECONDARY;
    uint16 sk_latest_version = Rdb_key_def::SECONDARY_FORMAT_VERSION_LATEST;
    kv_version = sk_latest_version;
  }

  const char *const key_name = get_key_name(i, table_arg, m_tbl_def);
  *new_key_def = std::make_shared<Rdb_key_def>(
      index_id, i, cf_info.cf_handle, index_dict_version, index_type,
      kv_version, cf_info.is_reverse_cf, cf_info.is_auto_cf, key_name);

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

int rdb_normalize_tablename(const std::string &tablename,
                            std::string *const strbuf) {
  DBUG_ASSERT(strbuf != nullptr);

  if (tablename.size() < 2 || tablename[0] != '.' || tablename[1] != '/') {
    DBUG_ASSERT(0); // We were not passed table name?
    return HA_ERR_INTERNAL_ERROR;
  }

  size_t pos = tablename.find_first_of('/', 2);
  if (pos == std::string::npos) {
    DBUG_ASSERT(0); // We were not passed table name?
    return HA_ERR_INTERNAL_ERROR;
  }

  *strbuf = tablename.substr(2, pos - 2) + "." + tablename.substr(pos + 1);

  return HA_EXIT_SUCCESS;
}

/*
  Check to see if the user's original statement includes foreign key
  references
*/
bool ha_rocksdb::contains_foreign_key(THD *const thd) {
  bool success;
  const char *str = thd_query_string(thd)->str;

  DBUG_ASSERT(str != nullptr);

  while (*str != '\0') {
    // Scan from our current pos looking for 'FOREIGN'
    str = rdb_find_in_string(str, "FOREIGN", &success);
    if (!success) {
      return false;
    }

    // Skip past the found "FOREIGN'
    str = rdb_check_next_token(&my_charset_bin, str, "FOREIGN", &success);
    DBUG_ASSERT(success);

    if (!my_isspace(&my_charset_bin, *str)) {
      return false;
    }

    // See if the next token is 'KEY'
    str = rdb_check_next_token(&my_charset_bin, str, "KEY", &success);
    if (!success) {
      continue;
    }

    // See if the next token is '('
    str = rdb_check_next_token(&my_charset_bin, str, "(", &success);
    if (!success) {
      // There is an optional index id after 'FOREIGN KEY', skip it
      str = rdb_skip_id(&my_charset_bin, str);

      // Now check for '(' again
      str = rdb_check_next_token(&my_charset_bin, str, "(", &success);
    }

    // If we have found 'FOREIGN KEY [<word>] (' we can be confident we have
    // a foreign key clause.
    return success;
  }

  // We never found a valid foreign key clause
  return false;
}

/**
  @brief
  splits the normalized table name of <dbname>.<tablename>#P#<part_no> into
  the <dbname>, <tablename> and <part_no> components.

  @param dbbuf returns database name/table_schema
  @param tablebuf returns tablename
  @param partitionbuf returns partition suffix if there is one
  @return HA_EXIT_SUCCESS on success, non-zero on failure to split
*/
int rdb_split_normalized_tablename(const std::string &fullname,
                                   std::string *const db,
                                   std::string *const table,
                                   std::string *const partition) {
  DBUG_ASSERT(!fullname.empty());

#define RDB_PARTITION_STR "#P#"

  /* Normalize returns dbname.tablename. */
  size_t dotpos = fullname.find('.');

  /* Invalid table name? */
  if (dotpos == std::string::npos) {
    return HA_ERR_INTERNAL_ERROR;
  }

  // Table must have a database name associated with it.
  DBUG_ASSERT(dotpos > 0);

  if (db != nullptr) {
    *db = fullname.substr(0, dotpos);
  }

  dotpos++;

  const size_t partpos =
      fullname.find(RDB_PARTITION_STR, dotpos, strlen(RDB_PARTITION_STR));

  if (partpos != std::string::npos) {
    DBUG_ASSERT(partpos >= dotpos);

    if (table != nullptr) {
      *table = fullname.substr(dotpos, partpos - dotpos);
    }

    if (partition != nullptr) {
      *partition = fullname.substr(partpos + strlen(RDB_PARTITION_STR));
    }
  } else if (table != nullptr) {
    *table = fullname.substr(dotpos);
  }

  return HA_EXIT_SUCCESS;
}

/**
  @brief
  create() is called to create a database. The variable name will have the name
  of the table.

  @details
  When create() is called you do not need to worry about
  opening the table. Also, the .frm file will have already been
  created so adjusting create_info is not necessary. You can overwrite
  the .frm file at this point if you wish to change the table
  definition, but there are no methods currently provided for doing
  so.

  Called from handle.cc by ha_create_table().

  @see
  ha_create_table() in handle.cc
*/

int ha_rocksdb::create(const char *const name, TABLE *const table_arg,
                       HA_CREATE_INFO *const create_info) {
  DBUG_ENTER_FUNC();

  int res;
  std::string str;

  THD *const thd = my_core::thd_get_current_thd();

  if (get_table_if_exists(name)) {
    if (thd->lex->sql_command == SQLCOM_TRUNCATE) {
      if (delete_table(name)) {
        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
      }
    } else {
      if (rdb_normalize_tablename(name, &str)) {
        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
      }
      my_printf_error(
          ER_UNKNOWN_ERROR,
          "Table '%s' does not exist, but metadata information exists inside "
          "MyRocks. This is a sign of data inconsistency. Please check if "
          "'%s.frm' exists, and try to restore it if it does not exist.",
          MYF(0), str.c_str(), name);
      DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
    }
  }

  /*
    Construct dbname.tablename ourselves, because parititioning
    passes strings like "./test/t14#P#p0" for individual partitions,
    while table_arg->s->table_name has none of that.
  */
  if (rdb_normalize_tablename(name, &str)) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  if (contains_foreign_key(thd)) {
    my_printf_error(ER_NOT_SUPPORTED_YET, "MyRocks does not currently support "
                                          "foreign key constraints",
                    MYF(0));
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  /*
    TODO(alexyang): Temporarily disable unique indexes support when there is no
    Primary Key
  */
  for (uint keyno = 0; keyno < table_arg->s->keys; keyno++) {
    if ((table_arg->key_info[keyno].flags & HA_NOSAME) &&
        has_hidden_pk(table_arg)) {
      my_printf_error(ER_UNKNOWN_ERROR, "Unique index support is disabled when "
                                        "the table has no primary key. ",
                      MYF(0));
      DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
    }
  }

  bool write_err = false;
  const std::unique_ptr<rocksdb::WriteBatch> wb = dict_manager.begin();
  rocksdb::WriteBatch *const batch = wb.get();

  /* Create table/key descriptions and put them into the data dictionary */
  m_tbl_def = new Rdb_tbl_def(str);

  uint n_keys = table_arg->s->keys;

  /*
    If no primary key found, create a hidden PK and place it inside table
    definition
  */
  if (has_hidden_pk(table_arg)) {
    n_keys += 1;
  }

  m_key_descr_arr = new std::shared_ptr<Rdb_key_def>[n_keys];
  m_tbl_def->m_key_count = n_keys;
  m_tbl_def->m_key_descr_arr = m_key_descr_arr;

  if ((res = create_key_defs(table_arg, m_tbl_def))) {
    goto error;
  }

  m_pk_descr = m_key_descr_arr[pk_index(table_arg, m_tbl_def)];

  dict_manager.lock();
  write_err =
      ddl_manager.put_and_write(m_tbl_def, batch) || dict_manager.commit(batch);
  dict_manager.unlock();

  if (write_err) {
    goto error;
  }

  if (create_info->auto_increment_value)
    m_tbl_def->m_auto_incr_val = create_info->auto_increment_value;

  /*
    We only support auto_increment at start of the PRIMARY KEY.
  */
  // Field *field;
  // if ((field= table_arg->next_number_field))
  /* TODO mdcallag: disable this for now to let UNIQUE indexes kind of work
  if ((field= table_arg->found_next_number_field))
  {
    int pk= table_arg->s->primary_key;
    Field *pk_field= table_arg->key_info[pk].key_part[0].field;
    if (field->field_index !=  pk_field->field_index)
      DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }
  */
  DBUG_RETURN(HA_EXIT_SUCCESS);

error:
  /* Delete what we have allocated so far */
  delete m_tbl_def;
  m_tbl_def = nullptr;
  m_key_descr_arr = nullptr;

  DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
}

/**
  @note
  This function is used only when the table has not yet been opened, and
  keyread_allowed bitmap doesn't have the correct values yet.

  See comment in ha_rocksdb::index_flags() for details.
*/

bool ha_rocksdb::check_keyread_allowed(uint inx, uint part,
                                       bool all_parts) const {
  bool res = true;
  KEY *const key_info = &table_share->key_info[inx];

  Rdb_field_packing dummy1;
  res = dummy1.setup(nullptr, key_info->key_part[part].field, inx, part,
                     key_info->key_part[part].length);

  if (res && all_parts) {
    for (uint i = 0; i < part; i++) {
      Field *field;
      if ((field = key_info->key_part[i].field)) {
        Rdb_field_packing dummy;
        if (!dummy.setup(nullptr, field, inx, i,
                         key_info->key_part[i].length)) {
          /* Cannot do index-only reads for this column */
          res = false;
          break;
        }
      }
    }
  }

  const uint pk = table_share->primary_key;
  if (inx == pk && all_parts &&
      part + 1 == table_share->key_info[pk].user_defined_key_parts) {
    m_pk_can_be_decoded = res;
  }

  return res;
}

int ha_rocksdb::read_key_exact(const Rdb_key_def &kd,
                               rocksdb::Iterator *const iter,
                               const bool &full_key_match,
                               const rocksdb::Slice &key_slice) const {
  DBUG_ASSERT(iter != nullptr);

  /*
    We are looking for the first record such that
      index_tuple= lookup_tuple.
    lookup_tuple may be a prefix of the index.
  */
  if (kd.m_is_reverse_cf) {
    if (!full_key_match) {
      if (!iter->Valid())
        iter->SeekToLast();
      else
        iter->Prev();
    }
  }

  if (!iter->Valid() || !kd.value_matches_prefix(iter->key(), key_slice)) {
    /*
      Got a record that is not equal to the lookup value, or even a record
      from another table.index.
    */
    return HA_ERR_KEY_NOT_FOUND;
  }
  return HA_EXIT_SUCCESS;
}

int ha_rocksdb::read_before_key(const Rdb_key_def &kd,
                                const bool &full_key_match,
                                const rocksdb::Slice &key_slice) {
  /*
    We are looking for record with the biggest t.key such that
    t.key < lookup_tuple.
  */
  if (kd.m_is_reverse_cf) {
    if (m_scan_it->Valid() && full_key_match &&
        kd.value_matches_prefix(m_scan_it->key(), key_slice)) {
      /* We are using full key and we've hit an exact match */
      m_scan_it->Next();
    }
  } else {
    if (m_scan_it->Valid())
      m_scan_it->Prev();
    else
      m_scan_it->SeekToLast();
  }

  return m_scan_it->Valid() ? HA_EXIT_SUCCESS : HA_ERR_KEY_NOT_FOUND;
}

int ha_rocksdb::read_after_key(const Rdb_key_def &kd,
                               const bool &full_key_match,
                               const rocksdb::Slice &key_slice) {
  /*
    We are looking for the first record such that

      index_tuple $GT lookup_tuple

    with HA_READ_AFTER_KEY, $GT = '>',
    with HA_READ_KEY_OR_NEXT, $GT = '>='
  */
  if (kd.m_is_reverse_cf) {
    if (!m_scan_it->Valid()) {
      m_scan_it->SeekToLast();
    } else {
      /*
        We should step back
         - when not using full extended key
         - when using full extended key and when we've got an exact match
      */
      if (!full_key_match ||
          !kd.value_matches_prefix(m_scan_it->key(), key_slice)) {
        m_scan_it->Prev();
      }
    }
  }

  return m_scan_it->Valid() ? HA_EXIT_SUCCESS : HA_ERR_KEY_NOT_FOUND;
}

int ha_rocksdb::position_to_correct_key(const Rdb_key_def &kd,
                                        const enum ha_rkey_function &find_flag,
                                        const bool &full_key_match,
                                        const uchar *const key,
                                        const key_part_map &keypart_map,
                                        const rocksdb::Slice &key_slice,
                                        bool *const move_forward) {
  int rc = 0;

  *move_forward = true;

  switch (find_flag) {
  case HA_READ_KEY_EXACT:
    rc = read_key_exact(kd, m_scan_it, full_key_match, key_slice);
    break;
  case HA_READ_BEFORE_KEY:
    *move_forward = false;
    rc = read_before_key(kd, full_key_match, key_slice);
    if (rc == 0 && !kd.covers_key(m_scan_it->key())) {
      /* The record we've got is not from this index */
      rc = HA_ERR_KEY_NOT_FOUND;
    }
    break;
  case HA_READ_AFTER_KEY:
  case HA_READ_KEY_OR_NEXT:
    rc = read_after_key(kd, full_key_match, key_slice);
    if (rc == 0 && !kd.covers_key(m_scan_it->key())) {
      /* The record we've got is not from this index */
      rc = HA_ERR_KEY_NOT_FOUND;
    }
    break;
  case HA_READ_KEY_OR_PREV:
  case HA_READ_PREFIX:
    /* This flag is not used by the SQL layer, so we don't support it yet. */
    rc = HA_ERR_UNSUPPORTED;
    break;
  case HA_READ_PREFIX_LAST:
  case HA_READ_PREFIX_LAST_OR_PREV:
    *move_forward = false;
    /*
      Find the last record with the specified index prefix lookup.
      - HA_READ_PREFIX_LAST requires that the record has the
        prefix=lookup (if there are no such records,
        HA_ERR_KEY_NOT_FOUND should be returned).
      - HA_READ_PREFIX_LAST_OR_PREV has no such requirement. If there are no
        records with prefix=lookup, we should return the last record
        before that.
    */
    rc = read_before_key(kd, full_key_match, key_slice);
    if (rc == 0) {
      const rocksdb::Slice &rkey = m_scan_it->key();
      if (!kd.covers_key(rkey)) {
        /* The record we've got is not from this index */
        rc = HA_ERR_KEY_NOT_FOUND;
      } else if (find_flag == HA_READ_PREFIX_LAST) {
        uint size = kd.pack_index_tuple(table, m_pack_buffer, m_sk_packed_tuple,
                                        key, keypart_map);
        rocksdb::Slice lookup_tuple(reinterpret_cast<char *>(m_sk_packed_tuple),
                                    size);

        // We need to compare the key we've got with the original search prefix.
        if (!kd.value_matches_prefix(rkey, lookup_tuple)) {
          rc = HA_ERR_KEY_NOT_FOUND;
        }
      }
    }
    break;
  default:
    DBUG_ASSERT(0);
    break;
  }

  return rc;
}

int ha_rocksdb::calc_eq_cond_len(const Rdb_key_def &kd,
                                 const enum ha_rkey_function &find_flag,
                                 const rocksdb::Slice &slice,
                                 const int &bytes_changed_by_succ,
                                 const key_range *const end_key,
                                 uint *const end_key_packed_size) {
  if (find_flag == HA_READ_KEY_EXACT)
    return slice.size();

  if (find_flag == HA_READ_PREFIX_LAST) {
    /*
      We have made the kd.successor(m_sk_packed_tuple) call above.

      The slice is at least Rdb_key_def::INDEX_NUMBER_SIZE bytes long.
    */
    return slice.size() - bytes_changed_by_succ;
  }

  if (end_key) {
    *end_key_packed_size =
        kd.pack_index_tuple(table, m_pack_buffer, m_end_key_packed_tuple,
                            end_key->key, end_key->keypart_map);

    /*
      Calculating length of the equal conditions here. 4 byte index id is
      included.
      Example1: id1 BIGINT, id2 INT, id3 BIGINT, PRIMARY KEY (id1, id2, id3)
       WHERE id1=1 AND id2=1 AND id3>=2 => eq_cond_len= 4+8+4= 16
       WHERE id1=1 AND id2>=1 AND id3>=2 => eq_cond_len= 4+8= 12
      Example2: id1 VARCHAR(30), id2 INT, PRIMARY KEY (id1, id2)
       WHERE id1 = 'AAA' and id2 < 3; => eq_cond_len=13 (varchar used 9 bytes)
    */
    rocksdb::Slice end_slice(reinterpret_cast<char *>(m_end_key_packed_tuple),
                             *end_key_packed_size);
    return slice.difference_offset(end_slice);
  }

  /*
    On range scan without any end key condition, there is no
    eq cond, and eq cond length is the same as index_id size (4 bytes).
    Example1: id1 BIGINT, id2 INT, id3 BIGINT, PRIMARY KEY (id1, id2, id3)
     WHERE id1>=1 AND id2 >= 2 and id2 <= 5 => eq_cond_len= 4
  */
  return Rdb_key_def::INDEX_NUMBER_SIZE;
}

int ha_rocksdb::read_row_from_primary_key(uchar *const buf) {
  DBUG_ASSERT(buf != nullptr);

  int rc;
  const rocksdb::Slice &rkey = m_scan_it->key();
  const uint pk_size = rkey.size();
  const char *pk_data = rkey.data();

  memcpy(m_pk_packed_tuple, pk_data, pk_size);
  m_last_rowkey.copy(pk_data, pk_size, &my_charset_bin);

  if (m_lock_rows != RDB_LOCK_NONE) {
    /* We need to put a lock and re-read */
    rc = get_row_by_rowid(buf, m_pk_packed_tuple, pk_size);
  } else {
    /* Unpack from the row we've read */
    const rocksdb::Slice &value = m_scan_it->value();
    rc = convert_record_from_storage_format(&rkey, &value, buf);
  }

  return rc;
}

int ha_rocksdb::read_row_from_secondary_key(uchar *const buf,
                                            const Rdb_key_def &kd,
                                            bool move_forward) {
  DBUG_ASSERT(buf != nullptr);

  int rc = 0;
  uint pk_size;

  if (m_keyread_only && m_lock_rows == RDB_LOCK_NONE && !has_hidden_pk(table)) {
    /* Get the key columns and primary key value */
    const rocksdb::Slice &rkey = m_scan_it->key();
    pk_size =
        kd.get_primary_key_tuple(table, *m_pk_descr, &rkey, m_pk_packed_tuple);
    const rocksdb::Slice &value = m_scan_it->value();
    if (pk_size == RDB_INVALID_KEY_LEN ||
        kd.unpack_record(table, buf, &rkey, &value,
                         m_verify_row_debug_checksums)) {
      rc = HA_ERR_INTERNAL_ERROR;
    }
  } else {
    if (kd.m_is_reverse_cf)
      move_forward = !move_forward;

    rc = find_icp_matching_index_rec(move_forward, buf);
    if (!rc) {
      const rocksdb::Slice &rkey = m_scan_it->key();
      pk_size = kd.get_primary_key_tuple(table, *m_pk_descr, &rkey,
                                         m_pk_packed_tuple);
      if (pk_size == RDB_INVALID_KEY_LEN) {
        rc = HA_ERR_INTERNAL_ERROR;
      } else {
        rc = get_row_by_rowid(buf, m_pk_packed_tuple, pk_size);
      }
    }
  }

  if (!rc) {
    m_last_rowkey.copy((const char *)m_pk_packed_tuple, pk_size,
                       &my_charset_bin);
  }

  return rc;
}

/**
  @note
    The problem with this function is that SQL layer calls it, when
     - the table has not been yet opened (no ::open() call done)
     - this->table_share already exists, but it is in the process of being
       filled, so some of fields are still NULL.
     - In particular, table_share->key_info[inx].key_part[] is filled only up
       to part #part. Subsequent key parts are not yet filled.

    To complicate things further, SQL layer will call index_flags() with
    all_parts=TRUE. Essentially, we're asked to provide flags for reading
    keyparts whose datatype is not yet known.

    We walk around this problem by using check_keyread_allowed(), which uses
    table_share object and is careful not to step on unitialized data.

    When we get a call with all_parts=TRUE, we try to analyze all parts but
    ignore those that have key_part->field==nullptr (these are not initialized
    yet).
*/

ulong ha_rocksdb::index_flags(uint inx, uint part, bool all_parts) const {
  DBUG_ENTER_FUNC();

  ulong base_flags = HA_READ_NEXT | // doesn't seem to be used
                     HA_READ_ORDER | HA_READ_RANGE | HA_READ_PREV;

  if (check_keyread_allowed(inx, part, all_parts))
    base_flags |= HA_KEYREAD_ONLY;

  if (inx == table_share->primary_key) {
    /*
      Index-only reads on primary key are the same as table scan for us. Still,
      we need to explicitly "allow" them, otherwise SQL layer will miss some
      plans.
    */
    base_flags |= HA_KEYREAD_ONLY;
  } else {
    /*
      We can Index Condition Pushdown any key except the primary. With primary
      key, we get (pk, record) pair immediately, there is no place to put the
      ICP check.
    */
    base_flags |= HA_DO_INDEX_COND_PUSHDOWN;
  }

  DBUG_RETURN(base_flags);
}

/**
  @brief
  Read next index tuple through the secondary index.

  @details
  m_scan_it points at the index key-value pair that we should read the (pk,row)
  pair for.
*/
int ha_rocksdb::secondary_index_read(const int keyno, uchar *const buf) {
  DBUG_ASSERT(buf != nullptr);
  DBUG_ASSERT(table != nullptr);

  /* Use STATUS_NOT_FOUND when record not found or some error occurred */
  table->status = STATUS_NOT_FOUND;

  if (m_scan_it->Valid()) {
    rocksdb::Slice key = m_scan_it->key();

    /* Check if we've ran out of records of this index */
    if (m_key_descr_arr[keyno]->covers_key(key)) {
      int rc = 0;

      // TODO: We could here check if we have ran out of range we're scanning
      const uint size = m_key_descr_arr[keyno]->get_primary_key_tuple(
          table, *m_pk_descr, &key, m_pk_packed_tuple);
      if (size == RDB_INVALID_KEY_LEN) {
        return HA_ERR_INTERNAL_ERROR;
      }

      m_last_rowkey.copy((const char *)m_pk_packed_tuple, size,
                         &my_charset_bin);

      if (m_keyread_only && m_lock_rows == RDB_LOCK_NONE &&
          !has_hidden_pk(table)) {
        rocksdb::Slice value = m_scan_it->value();
        if (m_key_descr_arr[keyno]->unpack_record(
                table, buf, &key, &value, m_verify_row_debug_checksums)) {
          return HA_ERR_INTERNAL_ERROR;
        }
      } else {
        rc = get_row_by_rowid(buf, m_pk_packed_tuple, size);
      }

      if (!rc) {
        table->status = 0;
        update_row_stats(ROWS_READ);
      }
      return rc;
    }
  }
  return HA_ERR_END_OF_FILE;
}

/*
  ha_rocksdb::read_range_first overrides handler::read_range_first.
  The only difference from handler::read_range_first is that
  ha_rocksdb::read_range_first passes end_key to
  ha_rocksdb::index_read_map_impl function.
*/
int ha_rocksdb::read_range_first(const key_range *const start_key,
                                 const key_range *const end_key,
                                 bool eq_range_arg, bool sorted) {
  DBUG_ENTER_FUNC();

  int result;

  eq_range = eq_range_arg;
  set_end_range(end_key, RANGE_SCAN_ASC);

  range_key_part = table->key_info[active_index].key_part;

  if (!start_key) // Read first record
    result = ha_index_first(table->record[0]);
  else {
    if (is_using_prohibited_gap_locks(
            table,
            is_using_full_unique_key(active_index, start_key->keypart_map,
                                     start_key->flag))) {
      DBUG_RETURN(HA_ERR_LOCK_DEADLOCK);
    }

    MYSQL_TABLE_IO_WAIT(m_psi, PSI_TABLE_FETCH_ROW, active_index, 0, {
      result =
          index_read_map_impl(table->record[0], start_key->key,
                              start_key->keypart_map, start_key->flag, end_key);
    })
  }
  if (result)
    DBUG_RETURN((result == HA_ERR_KEY_NOT_FOUND) ? HA_ERR_END_OF_FILE : result);

  if (compare_key(end_range) <= 0) {
    DBUG_RETURN(HA_EXIT_SUCCESS);
  } else {
    /*
      The last read row does not fall in the range. So request
      storage engine to release row lock if possible.
    */
    unlock_row();
    DBUG_RETURN(HA_ERR_END_OF_FILE);
  }
}

int ha_rocksdb::index_read_map(uchar *const buf, const uchar *const key,
                               key_part_map keypart_map,
                               enum ha_rkey_function find_flag) {
  DBUG_ENTER_FUNC();

  DBUG_RETURN(index_read_map_impl(buf, key, keypart_map, find_flag, nullptr));
}

/*
   See storage/rocksdb/rocksdb-range-access.txt for description of how MySQL
   index navigation commands are converted into RocksDB lookup commands.

   This function takes end_key as an argument, and it is set on range scan.
   MyRocks needs to decide whether prefix bloom filter can be used or not.
   To decide to use prefix bloom filter or not, calculating equal condition
   length
   is needed. On equal lookups (find_flag == HA_READ_KEY_EXACT), equal
   condition length is the same as rocksdb::Slice.size() of the start key.
   On range scan, equal condition length is MIN(start_key, end_key) of the
   rocksdb::Slice expression.
*/
int ha_rocksdb::index_read_map_impl(uchar *const buf, const uchar *const key,
                                    key_part_map keypart_map,
                                    enum ha_rkey_function find_flag,
                                    const key_range *end_key) {
  DBUG_ENTER_FUNC();

  int rc = 0;

  ha_statistic_increment(&SSV::ha_read_key_count);
  const Rdb_key_def &kd = *m_key_descr_arr[active_index];
  const uint actual_key_parts = kd.get_key_parts();
  bool using_full_key = is_using_full_key(keypart_map, actual_key_parts);

  if (!end_key)
    end_key = end_range;

  /* By default, we don't need the retrieved records to match the prefix */
  m_sk_match_prefix = nullptr;

  if (active_index == table->s->primary_key && find_flag == HA_READ_KEY_EXACT &&
      using_full_key) {
    /*
      Equality lookup over primary key, using full tuple.
      This is a special case, use DB::Get.
    */
    const uint size = kd.pack_index_tuple(table, m_pack_buffer,
                                          m_pk_packed_tuple, key, keypart_map);
    rc = get_row_by_rowid(buf, m_pk_packed_tuple, size);
    if (!rc) {
      update_row_stats(ROWS_READ);
    }
    DBUG_RETURN(rc);
  }

  /*
    Unique secondary index performs lookups without the extended key fields
  */
  uint packed_size;
  if (active_index != table->s->primary_key &&
      table->key_info[active_index].flags & HA_NOSAME &&
      find_flag == HA_READ_KEY_EXACT && using_full_key) {
    key_part_map tmp_map = (key_part_map(1) << table->key_info[active_index]
                                                   .user_defined_key_parts) -
                           1;
    packed_size = kd.pack_index_tuple(table, m_pack_buffer, m_sk_packed_tuple,
                                      key, tmp_map);
    if (table->key_info[active_index].user_defined_key_parts !=
        kd.get_key_parts())
      using_full_key = false;
  } else {
    packed_size = kd.pack_index_tuple(table, m_pack_buffer, m_sk_packed_tuple,
                                      key, keypart_map);
  }

  if ((pushed_idx_cond && pushed_idx_cond_keyno == active_index) &&
      (find_flag == HA_READ_KEY_EXACT || find_flag == HA_READ_PREFIX_LAST)) {
    /*
      We are doing a point index lookup, and ICP is enabled. It is possible
      that this call will be followed by ha_rocksdb->index_next_same() call.

      Do what InnoDB does: save the lookup tuple now. We will need it in
      index_next_same/find_icp_matching_index_rec in order to stop scanning
      as soon as index record doesn't match the lookup tuple.

      When not using ICP, handler::index_next_same() will make sure that rows
      that don't match the lookup prefix are not returned.
      row matches the lookup prefix.
    */
    m_sk_match_prefix = m_sk_match_prefix_buf;
    m_sk_match_length = packed_size;
    memcpy(m_sk_match_prefix, m_sk_packed_tuple, packed_size);
  }

  int bytes_changed_by_succ = 0;
  if (find_flag == HA_READ_PREFIX_LAST_OR_PREV ||
      find_flag == HA_READ_PREFIX_LAST || find_flag == HA_READ_AFTER_KEY) {
    /* See below */
    bytes_changed_by_succ = kd.successor(m_sk_packed_tuple, packed_size);
  }

  rocksdb::Slice slice(reinterpret_cast<const char *>(m_sk_packed_tuple),
                       packed_size);

  uint end_key_packed_size = 0;
  const uint eq_cond_len =
      calc_eq_cond_len(kd, find_flag, slice, bytes_changed_by_succ, end_key,
                       &end_key_packed_size);

  bool use_all_keys = false;
  if (find_flag == HA_READ_KEY_EXACT &&
      my_count_bits(keypart_map) == kd.get_key_parts())
    use_all_keys = true;

  Rdb_transaction *const tx = get_or_create_tx(table->in_use);
  const bool is_new_snapshot = !tx->has_snapshot();
  // Loop as long as we get a deadlock error AND we end up creating the
  // snapshot here (i.e. it did not exist prior to this)
  for (;;) {
    /*
      This will open the iterator and position it at a record that's equal or
      greater than the lookup tuple.
    */
    setup_scan_iterator(kd, &slice, use_all_keys, is_ascending(kd, find_flag),
                        eq_cond_len);

    /*
      Once we are positioned on from above, move to the position we really
      want: See storage/rocksdb/rocksdb-range-access.txt
    */
    bool move_forward;
    rc = position_to_correct_key(kd, find_flag, using_full_key, key,
                                 keypart_map, slice, &move_forward);

    if (rc) {
      /* This status is returned on any error */
      table->status = STATUS_NOT_FOUND;
      DBUG_RETURN(rc);
    }

    m_skip_scan_it_next_call = false;

    /*
      Now get the data for the row into 'buf'.  If we were using a primary key
      then we have all the rows we need.  For a secondary key we now need to
      lookup the primary key.
    */
    if (active_index == table->s->primary_key)
      rc = read_row_from_primary_key(buf);
    else
      rc = read_row_from_secondary_key(buf, kd, move_forward);

    if (rc != HA_ERR_LOCK_DEADLOCK || !is_new_snapshot)
      break; /* Exit the loop */

    // release the snapshot and iterator so they will be regenerated
    tx->release_snapshot();
    release_scan_iterator();
  }

  if (rc) {
    /* the only possible error condition is record-not-found */
    table->status = STATUS_NOT_FOUND;
  } else {
    table->status = 0;
    update_row_stats(ROWS_READ);
  }

  DBUG_RETURN(rc);
}

/*
  @brief
  Scan the secondary index until we find an index record that satisfies ICP

  @param move_forward   TRUE  <=> move m_scan_it forward
                        FALSE <=> move m_scan_it backward
  @param buf            Record buffer (must be the same buffer that
                        pushed index condition points to, in practice
                        it is table->record[0])

  @detail
  Move the current iterator m_scan_it until we get an index tuple that
  satisfies the pushed Index Condition.
  (if there is no pushed index condition, return right away)

  @return
    0     - Index tuple satisfies ICP, can do index read.
    other - error code
*/

int ha_rocksdb::find_icp_matching_index_rec(const bool &move_forward,
                                            uchar *const buf) {
  DBUG_ASSERT(buf != nullptr);

  if (pushed_idx_cond && pushed_idx_cond_keyno == active_index) {
    const Rdb_key_def &kd = *m_key_descr_arr[active_index];

    while (1) {
      if (!m_scan_it->Valid()) {
        table->status = STATUS_NOT_FOUND;
        return HA_ERR_END_OF_FILE;
      }
      const rocksdb::Slice rkey = m_scan_it->key();

      if (!kd.covers_key(rkey)) {
        table->status = STATUS_NOT_FOUND;
        return HA_ERR_END_OF_FILE;
      }

      if (m_sk_match_prefix) {
        const rocksdb::Slice prefix((const char *)m_sk_match_prefix,
                                    m_sk_match_length);
        if (!kd.value_matches_prefix(rkey, prefix)) {
          table->status = STATUS_NOT_FOUND;
          return HA_ERR_END_OF_FILE;
        }
      }

      const rocksdb::Slice value = m_scan_it->value();
      if (kd.unpack_record(table, buf, &rkey, &value,
                           m_verify_row_debug_checksums)) {
        return HA_ERR_INTERNAL_ERROR;
      }

      const enum icp_result icp_status = check_index_cond();
      if (icp_status == ICP_NO_MATCH) {
        if (move_forward)
          m_scan_it->Next();
        else
          m_scan_it->Prev();
        continue; /* Get the next (or prev) index tuple */
      } else if (icp_status == ICP_OUT_OF_RANGE) {
        /* We have walked out of range we are scanning */
        table->status = STATUS_NOT_FOUND;
        return HA_ERR_END_OF_FILE;
      } else /* icp_status == ICP_MATCH */
      {
        /* Index Condition is satisfied. We have rc==0, proceed to fetch the
         * row. */
        break;
      }
      /*
        TODO: should we have this here, or RockDB handles this internally?
        if (my_core::thd_killed(current_thd))
        {
          rc= HA_ERR_INTERNAL_ERROR; // doesn't matter
          break;
        }
      */
    }
  }
  return HA_EXIT_SUCCESS;
}

int ha_rocksdb::index_read_last_map(uchar *const buf, const uchar *const key,
                                    key_part_map keypart_map) {
  DBUG_ENTER_FUNC();

  DBUG_RETURN(index_read_map(buf, key, keypart_map, HA_READ_PREFIX_LAST));
}

int ha_rocksdb::check(THD *const thd, HA_CHECK_OPT *const check_opt) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(thd != nullptr);
  DBUG_ASSERT(check_opt != nullptr);

  const uint pk = pk_index(table, m_tbl_def);
  String rowkey_copy;
  String sec_key_copy;
  const char *const table_name = table->s->table_name.str;

  // Only when debugging: don't use snapshot when reading
  // Rdb_transaction *tx= get_or_create_tx(table->in_use);
  // tx->snapshot= nullptr;

  const bool save_verify_row_debug_checksums = m_verify_row_debug_checksums;
  m_verify_row_debug_checksums = true;

  /* For each secondary index, check that we can get a PK value from it */
  // NO_LINT_DEBUG
  sql_print_information("CHECKTABLE %s: Checking table %s", table_name,
                        table_name);
  ha_rows UNINIT_VAR(row_checksums_at_start); // set/used iff first_index==true
  ha_rows row_checksums = ha_rows(-1);
  bool first_index = true;

  for (uint keyno = 0; keyno < table->s->keys; keyno++) {
    if (keyno != pk) {
      extra(HA_EXTRA_KEYREAD);
      ha_index_init(keyno, true);
      ha_rows rows = 0;
      ha_rows checksums = 0;
      if (first_index)
        row_checksums_at_start = m_row_checksums_checked;
      int res;
      // NO_LINT_DEBUG
      sql_print_information("CHECKTABLE %s:   Checking index %s", table_name,
                            table->key_info[keyno].name);
      while (1) {
        if (!rows)
          res = index_first(table->record[0]);
        else
          res = index_next(table->record[0]);

        if (res == HA_ERR_END_OF_FILE)
          break;
        if (res) {
          // error
          // NO_LINT_DEBUG
          sql_print_error("CHECKTABLE %s:   .. row %lld: index scan error %d",
                          table_name, rows, res);
          goto error;
        }
        rocksdb::Slice key = m_scan_it->key();
        sec_key_copy.copy(key.data(), key.size(), &my_charset_bin);
        rowkey_copy.copy(m_last_rowkey.ptr(), m_last_rowkey.length(),
                         &my_charset_bin);

        if (m_key_descr_arr[keyno]->unpack_info_has_checksum(
                m_scan_it->value())) {
          checksums++;
        }

        if ((res = get_row_by_rowid(table->record[0], rowkey_copy.ptr(),
                                    rowkey_copy.length()))) {
          // NO_LINT_DEBUG
          sql_print_error("CHECKTABLE %s:   .. row %lld: "
                          "failed to fetch row by rowid",
                          table_name, rows);
          goto error;
        }

        longlong hidden_pk_id = 0;
        if (has_hidden_pk(table) &&
            read_hidden_pk_id_from_rowkey(&hidden_pk_id))
          goto error;

        /* Check if we get the same PK value */
        uint packed_size = m_pk_descr->pack_record(
            table, m_pack_buffer, table->record[0], m_pk_packed_tuple, nullptr,
            false, hidden_pk_id);
        if (packed_size != rowkey_copy.length() ||
            memcmp(m_pk_packed_tuple, rowkey_copy.ptr(), packed_size)) {
          // NO_LINT_DEBUG
          sql_print_error("CHECKTABLE %s:   .. row %lld: PK value mismatch",
                          table_name, rows);
          goto print_and_error;
        }

        /* Check if we get the same secondary key value */
        packed_size = m_key_descr_arr[keyno]->pack_record(
            table, m_pack_buffer, table->record[0], m_sk_packed_tuple,
            &m_sk_tails, false, hidden_pk_id);
        if (packed_size != sec_key_copy.length() ||
            memcmp(m_sk_packed_tuple, sec_key_copy.ptr(), packed_size)) {
          // NO_LINT_DEBUG
          sql_print_error("CHECKTABLE %s:   .. row %lld: "
                          "secondary index value mismatch",
                          table_name, rows);
          goto print_and_error;
        }
        rows++;
        continue;

      print_and_error : {
        std::string buf;
        buf = rdb_hexdump(rowkey_copy.ptr(), rowkey_copy.length(),
                          RDB_MAX_HEXDUMP_LEN);
        // NO_LINT_DEBUG
        sql_print_error("CHECKTABLE %s:   rowkey: %s", table_name, buf.c_str());

        buf = rdb_hexdump(m_retrieved_record.data(), m_retrieved_record.size(),
                          RDB_MAX_HEXDUMP_LEN);
        // NO_LINT_DEBUG
        sql_print_error("CHECKTABLE %s:   record: %s", table_name, buf.c_str());

        buf = rdb_hexdump(sec_key_copy.ptr(), sec_key_copy.length(),
                          RDB_MAX_HEXDUMP_LEN);
        // NO_LINT_DEBUG
        sql_print_error("CHECKTABLE %s:   index: %s", table_name, buf.c_str());

        goto error;
      }
      }
      // NO_LINT_DEBUG
      sql_print_information("CHECKTABLE %s:   ... %lld index entries checked "
                            "(%lld had checksums)",
                            table_name, rows, checksums);

      if (first_index) {
        row_checksums = m_row_checksums_checked - row_checksums_at_start;
        first_index = false;
      }
      ha_index_end();
    }
  }
  if (row_checksums != ha_rows(-1)) {
    // NO_LINT_DEBUG
    sql_print_information("CHECKTABLE %s:   %lld table records had checksums",
                          table_name, row_checksums);
  }
  extra(HA_EXTRA_NO_KEYREAD);

  m_verify_row_debug_checksums = save_verify_row_debug_checksums;
  /*
    TODO: we should check also for PK records that are missing in the secondary
    indexes.
    For that, need to walk through the PK and check that every PK record has a
    proper counterpart in each secondary index.
  */
  DBUG_RETURN(HA_ADMIN_OK);
error:
  m_verify_row_debug_checksums = save_verify_row_debug_checksums;
  ha_index_or_rnd_end();
  extra(HA_EXTRA_NO_KEYREAD);

  DBUG_RETURN(HA_ADMIN_CORRUPT);
}

static void dbug_dump_str(FILE *const out, const char *const str, int len) {
  fprintf(out, "\"");
  for (int i = 0; i < len; i++) {
    if (str[i] > 32)
      fprintf(out, "%c", str[i]);
    else
      fprintf(out, "\\%d", str[i]);
  }
  fprintf(out, "\"");
}

/*
  Debugging help: dump the whole database into a human-readable file.
  Usage:
    dbug_dump_database(rdb);
*/

void dbug_dump_database(rocksdb::DB *const db) {
  FILE *const out = fopen("/tmp/rocksdb.dump", "wt");
  if (!out)
    return;

  rocksdb::Iterator *it = db->NewIterator(rocksdb::ReadOptions());
  for (it->SeekToFirst(); it->Valid(); it->Next()) {
    rocksdb::Slice key = it->key();
    rocksdb::Slice val = it->value();
    dbug_dump_str(out, key.data(), key.size());
    fprintf(out, " -> ");
    dbug_dump_str(out, val.data(), val.size());
    fprintf(out, "\n");
  }

  delete it;
  fclose(out);
}

rocksdb::Status ha_rocksdb::get_for_update(
    Rdb_transaction *const tx, rocksdb::ColumnFamilyHandle *const column_family,
    const rocksdb::Slice &key, std::string *const value) const {
  DBUG_ASSERT(m_lock_rows != RDB_LOCK_NONE);
  const bool exclusive = m_lock_rows != RDB_LOCK_READ;

  rocksdb::Status s = tx->get_for_update(column_family, key, value, exclusive);

  // If we have a lock conflict and we are running in READ COMMITTTED mode
  // release and reacquire the snapshot and then retry the get_for_update().
  if (s.IsBusy() && !s.IsDeadlock() &&
      my_core::thd_tx_isolation(ha_thd()) == ISO_READ_COMMITTED) {
    tx->release_snapshot();
    tx->acquire_snapshot(false);

    s = tx->get_for_update(column_family, key, value, exclusive);
  }

  return s;
}

/*
  Given a rowid (i.e. packed PK) as a parameter, get the record.

  @return
    0      - Ok
    other  - HA_ERR error code.
*/

int ha_rocksdb::get_row_by_rowid(uchar *const buf, const char *const rowid,
                                 const uint rowid_size) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(buf != nullptr);
  DBUG_ASSERT(rowid != nullptr);
  DBUG_ASSERT(table != nullptr);

  int rc;

  rocksdb::Slice key_slice(rowid, rowid_size);

  Rdb_transaction *const tx = get_or_create_tx(table->in_use);
  DBUG_ASSERT(tx != nullptr);

  DEBUG_SYNC(ha_thd(), "rocksdb.get_row_by_rowid");
  DBUG_EXECUTE_IF("dbug.rocksdb.get_row_by_rowid", {
    THD *thd = ha_thd();
    const char act[] = "now signal Reached "
                       "wait_for signal.rocksdb.get_row_by_rowid_let_running";
    DBUG_ASSERT(opt_debug_sync_timeout > 0);
    DBUG_ASSERT(!debug_sync_set_action(thd, STRING_WITH_LEN(act)));
  };);

  bool found;
  rocksdb::Status s;

  if (m_lock_rows == RDB_LOCK_NONE) {
    tx->acquire_snapshot(true);
    s = tx->get(m_pk_descr->get_cf(), key_slice, &m_retrieved_record);
  } else {
    s = get_for_update(tx, m_pk_descr->get_cf(), key_slice,
                       &m_retrieved_record);
  }

  if (!s.IsNotFound() && !s.ok()) {
    DBUG_RETURN(tx->set_status_error(table->in_use, s, *m_pk_descr, m_tbl_def));
  }
  found = !s.IsNotFound();

  table->status = STATUS_NOT_FOUND;
  if (found) {
    m_last_rowkey.copy((const char *)rowid, rowid_size, &my_charset_bin);
    rc = convert_record_from_storage_format(&key_slice, buf);
    if (!rc)
      table->status = 0;
  } else {
    /*
      Note: we don't need to unlock the row. It is intentional that we keep
      locks on rows that don't exist.
    */
    rc = HA_ERR_KEY_NOT_FOUND;
  }

  DBUG_RETURN(rc);
}

int ha_rocksdb::index_next(uchar *const buf) {
  DBUG_ENTER_FUNC();

  bool moves_forward = true;
  ha_statistic_increment(&SSV::ha_read_next_count);
  if (m_key_descr_arr[active_index]->m_is_reverse_cf) {
    moves_forward = false;
  }

  int rc = index_next_with_direction(buf, moves_forward);
  if (rc == HA_ERR_KEY_NOT_FOUND)
    rc = HA_ERR_END_OF_FILE;

  DBUG_RETURN(rc);
}

int ha_rocksdb::index_prev(uchar *const buf) {
  DBUG_ENTER_FUNC();

  bool moves_forward = false;
  ha_statistic_increment(&SSV::ha_read_prev_count);
  if (m_key_descr_arr[active_index]->m_is_reverse_cf) {
    moves_forward = true;
  }

  int rc = index_next_with_direction(buf, moves_forward);
  if (rc == HA_ERR_KEY_NOT_FOUND)
    rc = HA_ERR_END_OF_FILE;

  DBUG_RETURN(rc);
}

int ha_rocksdb::index_next_with_direction(uchar *const buf, bool move_forward) {
  DBUG_ENTER_FUNC();

  int rc;

  if (active_index == pk_index(table, m_tbl_def)) {
    rc = rnd_next_with_direction(buf, move_forward);
  } else {
    if (m_skip_scan_it_next_call) {
      m_skip_scan_it_next_call = false;
    } else {
      if (move_forward)
        m_scan_it->Next(); /* this call cannot fail */
      else
        m_scan_it->Prev();
    }
    rc = find_icp_matching_index_rec(move_forward, buf);
    if (!rc)
      rc = secondary_index_read(active_index, buf);
  }

  DBUG_RETURN(rc);
}

int ha_rocksdb::index_first(uchar *const buf) {
  DBUG_ENTER_FUNC();

  m_sk_match_prefix = nullptr;
  ha_statistic_increment(&SSV::ha_read_first_count);
  int rc = m_key_descr_arr[active_index]->m_is_reverse_cf
               ? index_last_intern(buf)
               : index_first_intern(buf);
  if (rc == HA_ERR_KEY_NOT_FOUND)
    rc = HA_ERR_END_OF_FILE;

  DBUG_RETURN(rc);
}

int ha_rocksdb::index_last(uchar *const buf) {
  DBUG_ENTER_FUNC();

  m_sk_match_prefix = nullptr;
  ha_statistic_increment(&SSV::ha_read_last_count);
  int rc = m_key_descr_arr[active_index]->m_is_reverse_cf
               ? index_first_intern(buf)
               : index_last_intern(buf);
  if (rc == HA_ERR_KEY_NOT_FOUND)
    rc = HA_ERR_END_OF_FILE;

  DBUG_RETURN(rc);
}

/*
  Start scanning from the "first" value.

  The 'first' here means "the first from start of the key space".
  For reverse-ordered key spaces, the first value will be the biggest, 'zzzz'.

  An picture of a forward-ordered keyspace (remember, the keys have form
  'indexnr-keyval'. Suppose the index we are at has number n)

      (n-1) - ...
      ( n )          <--- 1. (n) doesn't exist in the db but it would be here.
      ( n ) - aaa       <--- 2. Seek("n") will put us here on the first index
      ( n ) - bbb               record.
      ( n ) - cc

  So, need to do: Seek(n);

  A backward-ordered keyspace:

      (n+1) - bbb
      (n+1) - aaa
      (n+1)        <--- (n+1) doesn't exist in the db but would be here.
      ( n ) - ccc       <--- 1. We need to be here.
      ( n ) - bbb
      ( n ) - aaa
      ( n )

  So, need to: Seek(n+1);

*/

int ha_rocksdb::index_first_intern(uchar *const buf) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(buf != nullptr);

  uchar *key;
  uint key_size;
  int rc;

  if (is_pk(active_index, table, m_tbl_def)) {
    key = m_pk_packed_tuple;
  } else {
    key = m_sk_packed_tuple;
  }

  DBUG_ASSERT(key != nullptr);

  const Rdb_key_def &kd = *m_key_descr_arr[active_index];
  if (kd.m_is_reverse_cf) {
    kd.get_supremum_key(key, &key_size);
  } else {
    kd.get_infimum_key(key, &key_size);
  }

  rocksdb::Slice index_key((const char *)key, key_size);

  Rdb_transaction *const tx = get_or_create_tx(table->in_use);
  DBUG_ASSERT(tx != nullptr);

  const bool is_new_snapshot = !tx->has_snapshot();
  // Loop as long as we get a deadlock error AND we end up creating the
  // snapshot here (i.e. it did not exist prior to this)
  for (;;) {
    setup_scan_iterator(kd, &index_key, false, !kd.m_is_reverse_cf,
                        Rdb_key_def::INDEX_NUMBER_SIZE);
    m_skip_scan_it_next_call = true;

    rc = index_next_with_direction(buf, true);
    if (rc != HA_ERR_LOCK_DEADLOCK || !is_new_snapshot)
      break; // exit the loop

    // release the snapshot and iterator so they will be regenerated
    tx->release_snapshot();
    release_scan_iterator();
  }

  DBUG_RETURN(rc);
}

/**
  @details
  Start scanning from the "last" value

  The 'last' here means "the last from start of the key space".
  For reverse-ordered key spaces, we will actually read the smallest value.

  An picture of a forward-ordered keyspace (remember, the keys have form
  'indexnr-keyval'. Suppose the we are at a key that has number n)

     (n-1)-something
     ( n )-aaa
     ( n )-bbb
     ( n )-ccc            <----------- Need to seek to here.
     (n+1)      <---- Doesn't exist, but would be here.
     (n+1)-smth, or no value at all

   RocksDB's Iterator::Seek($val) seeks to "at $val or first value that's
   greater". We can't see to "(n)-ccc" directly, because we don't know what
   is the value of 'ccc' (the biggest record with prefix (n)). Instead, we seek
   to "(n+1)", which is the least possible value that's greater than any value
   in index #n. Then we step one record back.

   So, need to:  it->Seek(n+1) || it->SeekToLast(); it->Prev();

   A backward-ordered keyspace:

      (n+1)-something
      ( n ) - ccc
      ( n ) - bbb
      ( n ) - aaa       <---------------- (*) Need to seek here.
      ( n ) <--- Doesn't exist, but would be here.
      (n-1)-smth, or no value at all

   So, need to:  it->Seek(n) || it->SeekToLast(); it->Prev();
*/

int ha_rocksdb::index_last_intern(uchar *const buf) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(buf != nullptr);

  uchar *key;
  uint key_size;
  int rc;

  if (is_pk(active_index, table, m_tbl_def)) {
    key = m_pk_packed_tuple;
  } else {
    key = m_sk_packed_tuple;
  }

  DBUG_ASSERT(key != nullptr);

  const Rdb_key_def &kd = *m_key_descr_arr[active_index];
  if (kd.m_is_reverse_cf) {
    kd.get_infimum_key(key, &key_size);
  } else {
    kd.get_supremum_key(key, &key_size);
  }

  rocksdb::Slice index_key((const char *)key, key_size);

  Rdb_transaction *const tx = get_or_create_tx(table->in_use);
  DBUG_ASSERT(tx != nullptr);

  const bool is_new_snapshot = !tx->has_snapshot();
  // Loop as long as we get a deadlock error AND we end up creating the
  // snapshot here (i.e. it did not exist prior to this)
  for (;;) {
    setup_scan_iterator(kd, &index_key, false, kd.m_is_reverse_cf,
                        Rdb_key_def::INDEX_NUMBER_SIZE);

    if (!m_scan_it->Valid()) {
      /*
        RocksDB keyspace has no records that follow our index. It could be, our
        index is the last in the keyspace. Navigate to last record in the
        keyspace.
      */
      m_scan_it->SeekToLast();
    } else {
      /*
        Iterator is pointing at some record right after the end of the index.
        Move one record back.
      */
      m_scan_it->Prev();
    }
    m_skip_scan_it_next_call = false;

    if (is_pk(active_index, table, m_tbl_def)) {
      m_skip_scan_it_next_call = true;
      rc = rnd_next_with_direction(buf, false);
    } else {
      rc = find_icp_matching_index_rec(false /*move_forward*/, buf);
      if (!rc)
        rc = secondary_index_read(active_index, buf);
    }

    if (rc != HA_ERR_LOCK_DEADLOCK || !is_new_snapshot)
      break; /* exit the loop */

    // release the snapshot and iterator so they will be regenerated
    tx->release_snapshot();
    release_scan_iterator();
  }

  DBUG_RETURN(rc);
}

void ha_rocksdb::unlock_row() {
  DBUG_ENTER_FUNC();

  if (m_lock_rows != RDB_LOCK_NONE) {
    Rdb_transaction *const tx = get_or_create_tx(table->in_use);
    tx->release_lock(m_pk_descr->get_cf(),
                     std::string(m_last_rowkey.ptr(), m_last_rowkey.length()));
  }

  DBUG_VOID_RETURN;
}

/*
  Returning true if SingleDelete can be used.
  - Secondary Indexes can always use SingleDelete.
  - If the index is PRIMARY KEY, and if all of the columns of the table
    are covered by the PRIMARY KEY, SingleDelete can be used.
*/
bool ha_rocksdb::can_use_single_delete(const uint &index) const {
  return (index != pk_index(table, m_tbl_def) ||
          (!has_hidden_pk(table) &&
           table->key_info[index].actual_key_parts == table->s->fields));
}

bool ha_rocksdb::skip_unique_check() const {
  /*
    We want to skip unique checks if:
      1) bulk_load is on
      2) the user set unique_checks option to 0
  */
  return THDVAR(table->in_use, bulk_load) ||
         my_core::thd_test_options(table->in_use, OPTION_RELAXED_UNIQUE_CHECKS);
}

bool ha_rocksdb::commit_in_the_middle() {
  return THDVAR(table->in_use, bulk_load) ||
         THDVAR(table->in_use, commit_in_the_middle);
}

/*
  Executing bulk commit if it should.
  @retval true if bulk commit failed
  @retval false if bulk commit was skipped or succeeded
*/
bool ha_rocksdb::do_bulk_commit(Rdb_transaction *const tx) {
  DBUG_ASSERT(tx != nullptr);
  return commit_in_the_middle() &&
         tx->get_write_count() >= THDVAR(table->in_use, bulk_load_size) &&
         tx->flush_batch();
}

/*
  If table was created without primary key, SQL layer represents the primary
  key number as MAX_INDEXES.  Hence, this function returns true if the table
  does not contain a primary key. (In which case we generate a hidden
  'auto-incremented' pk.)
*/
bool ha_rocksdb::has_hidden_pk(const TABLE *const table) const {
  DBUG_ASSERT(table != nullptr);
  return Rdb_key_def::table_has_hidden_pk(table);
}

/*
  Returns true if given index number is a hidden_pk.
  - This is used when a table is created with no primary key.
*/
bool ha_rocksdb::is_hidden_pk(const uint index, const TABLE *const table_arg,
                              const Rdb_tbl_def *const tbl_def_arg) {
  DBUG_ASSERT(table_arg != nullptr);
  DBUG_ASSERT(table_arg->s != nullptr);
  DBUG_ASSERT(tbl_def_arg != nullptr);

  return (table_arg->s->primary_key == MAX_INDEXES &&
          index == tbl_def_arg->m_key_count - 1);
}

/* Returns index of primary key */
uint ha_rocksdb::pk_index(const TABLE *const table_arg,
                          const Rdb_tbl_def *const tbl_def_arg) {
  DBUG_ASSERT(table_arg != nullptr);
  DBUG_ASSERT(table_arg->s != nullptr);
  DBUG_ASSERT(tbl_def_arg != nullptr);

  return table_arg->s->primary_key == MAX_INDEXES ? tbl_def_arg->m_key_count - 1
                                                  : table_arg->s->primary_key;
}

/* Returns true if given index number is a primary key */
bool ha_rocksdb::is_pk(const uint index, const TABLE *const table_arg,
                       const Rdb_tbl_def *const tbl_def_arg) {
  DBUG_ASSERT(table_arg != nullptr);
  DBUG_ASSERT(table_arg->s != nullptr);
  DBUG_ASSERT(tbl_def_arg != nullptr);

  return index == table_arg->s->primary_key ||
         is_hidden_pk(index, table_arg, tbl_def_arg);
}

const char *ha_rocksdb::get_key_name(const uint index,
                                     const TABLE *const table_arg,
                                     const Rdb_tbl_def *const tbl_def_arg) {
  DBUG_ASSERT(table_arg != nullptr);

  if (is_hidden_pk(index, table_arg, tbl_def_arg)) {
    return HIDDEN_PK_NAME;
  }

  return table_arg->key_info[index].name;
}

const char *ha_rocksdb::get_key_comment(const uint index,
                                        const TABLE *const table_arg,
                                        const Rdb_tbl_def *const tbl_def_arg) {
  DBUG_ASSERT(table_arg != nullptr);

  if (is_hidden_pk(index, table_arg, tbl_def_arg)) {
    return nullptr;
  }

  return table_arg->key_info[index].comment.str;
}

int ha_rocksdb::write_row(uchar *const buf) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(buf != nullptr);
  DBUG_ASSERT(buf == table->record[0]);
  DBUG_ASSERT(m_lock_rows == RDB_LOCK_WRITE);

  ha_statistic_increment(&SSV::ha_write_count);
  /*
    Note: "buf == table->record[0]" is copied from innodb. I am not aware of
    any use cases where this condition is not true.
  */
  if (table->next_number_field && buf == table->record[0]) {
    int err;
    if ((err = update_auto_increment())) {
      DBUG_RETURN(err);
    }
  }

  const int rv = update_write_row(nullptr, buf, skip_unique_check());

  if (rv == 0) {
    update_row_stats(ROWS_INSERTED);
  }

  DBUG_RETURN(rv);
}

/**
  Constructing m_last_rowkey (MyRocks key expression) from
  before_update|delete image (MySQL row expression).
  m_last_rowkey is normally set during lookup phase, such as
  rnd_next_with_direction() and rnd_pos(). With Read Free Replication,
  these read functions are skipped and update_rows(), delete_rows() are
  called without setting m_last_rowkey. This function sets m_last_rowkey
  for Read Free Replication.
*/
void ha_rocksdb::set_last_rowkey(const uchar *const old_data) {
  if (old_data && use_read_free_rpl()) {
    const int old_pk_size = m_pk_descr->pack_record(
        table, m_pack_buffer, old_data, m_pk_packed_tuple, nullptr, false);
    m_last_rowkey.copy((const char *)m_pk_packed_tuple, old_pk_size,
                       &my_charset_bin);
  }
}

int ha_rocksdb::get_pk_for_update(struct update_row_info *const row_info) {
  int size;

  /*
    Get new row key for any insert, and any update where the pk is not hidden.
    Row key for updates with hidden pk is handled below.
  */
  if (!has_hidden_pk(table)) {
    row_info->hidden_pk_id = 0;

    row_info->new_pk_unpack_info = &m_pk_unpack_info;

    size = m_pk_descr->pack_record(table, m_pack_buffer, row_info->new_data,
                                   m_pk_packed_tuple,
                                   row_info->new_pk_unpack_info, false);
  } else if (row_info->old_data == nullptr) {
    row_info->hidden_pk_id = update_hidden_pk_val();
    size =
        m_pk_descr->pack_hidden_pk(row_info->hidden_pk_id, m_pk_packed_tuple);
  } else {
    /*
      If hidden primary key, rowkey for new record will always be the same as
      before
    */
    size = row_info->old_pk_slice.size();
    memcpy(m_pk_packed_tuple, row_info->old_pk_slice.data(), size);
    if (read_hidden_pk_id_from_rowkey(&row_info->hidden_pk_id)) {
      return HA_ERR_INTERNAL_ERROR;
    }
  }

  row_info->new_pk_slice =
      rocksdb::Slice((const char *)m_pk_packed_tuple, size);

  return HA_EXIT_SUCCESS;
}

int ha_rocksdb::check_and_lock_unique_pk(const uint &key_id,
                                         const struct update_row_info &row_info,
                                         bool *const found,
                                         bool *const pk_changed) {
  DBUG_ASSERT(found != nullptr);
  DBUG_ASSERT(pk_changed != nullptr);

  *pk_changed = false;

  /*
    For UPDATEs, if the key has changed, we need to obtain a lock. INSERTs
    always require locking.
  */
  if (row_info.old_pk_slice.size() > 0) {
    /*
      If the keys are the same, then no lock is needed
    */
    if (!Rdb_pk_comparator::bytewise_compare(row_info.new_pk_slice,
                                             row_info.old_pk_slice)) {
      *found = false;
      return HA_EXIT_SUCCESS;
    }

    *pk_changed = true;
  }

  /*
    Perform a read to determine if a duplicate entry exists. For primary
    keys, a point lookup will be sufficient.

    note: we intentionally don't set options.snapshot here. We want to read
    the latest committed data.
  */

  /*
    To prevent race conditions like below, it is necessary to
    take a lock for a target row. get_for_update() holds a gap lock if
    target key does not exist, so below conditions should never
    happen.

    1) T1 Get(empty) -> T2 Get(empty) -> T1 Put(insert) -> T1 commit
       -> T2 Put(overwrite) -> T2 commit
    2) T1 Get(empty) -> T1 Put(insert, not committed yet) -> T2 Get(empty)
       -> T2 Put(insert, blocked) -> T1 commit -> T2 commit(overwrite)
  */
  const rocksdb::Status s =
      get_for_update(row_info.tx, m_pk_descr->get_cf(), row_info.new_pk_slice,
                     &m_retrieved_record);
  if (!s.ok() && !s.IsNotFound()) {
    return row_info.tx->set_status_error(table->in_use, s,
                                         *m_key_descr_arr[key_id], m_tbl_def);
  }

  *found = !s.IsNotFound();
  return HA_EXIT_SUCCESS;
}

int ha_rocksdb::check_and_lock_sk(const uint &key_id,
                                  const struct update_row_info &row_info,
                                  bool *const found) const {
  DBUG_ASSERT(found != nullptr);
  *found = false;

  /*
    Can skip checking this key if none of the key fields have changed.
  */
  if (row_info.old_data != nullptr && !m_update_scope.is_set(key_id)) {
    return HA_EXIT_SUCCESS;
  }

  KEY *key_info = nullptr;
  uint n_null_fields = 0;
  uint user_defined_key_parts = 1;

  key_info = &table->key_info[key_id];
  user_defined_key_parts = key_info->user_defined_key_parts;
  /*
    If there are no uniqueness requirements, there's no need to obtain a
    lock for this key.
  */
  if (!(key_info->flags & HA_NOSAME)) {
    return HA_EXIT_SUCCESS;
  }

  const Rdb_key_def &kd = *m_key_descr_arr[key_id];

  /*
    Calculate the new key for obtaining the lock

    For unique secondary indexes, the key used for locking does not
    include the extended fields.
  */
  int size =
      kd.pack_record(table, m_pack_buffer, row_info.new_data, m_sk_packed_tuple,
                     nullptr, false, 0, user_defined_key_parts, &n_null_fields);
  if (n_null_fields > 0) {
    /*
      If any fields are marked as NULL this will never match another row as
      to NULL never matches anything else including another NULL.
     */
    return HA_EXIT_SUCCESS;
  }

  const rocksdb::Slice new_slice =
      rocksdb::Slice((const char *)m_sk_packed_tuple, size);

  /*
    For UPDATEs, if the key has changed, we need to obtain a lock. INSERTs
    always require locking.
  */
  if (row_info.old_data != nullptr) {
    size = kd.pack_record(table, m_pack_buffer, row_info.old_data,
                          m_sk_packed_tuple_old, nullptr, false,
                          row_info.hidden_pk_id, user_defined_key_parts);
    const rocksdb::Slice old_slice =
        rocksdb::Slice((const char *)m_sk_packed_tuple_old, size);

    /*
      For updates, if the keys are the same, then no lock is needed

      Also check to see if the key has any fields set to NULL. If it does, then
      this key is unique since NULL is not equal to each other, so no lock is
      needed.
    */
    if (!Rdb_pk_comparator::bytewise_compare(new_slice, old_slice)) {
      return HA_EXIT_SUCCESS;
    }
  }

  /*
    Perform a read to determine if a duplicate entry exists - since this is
    a secondary indexes a range scan is needed.

    note: we intentionally don't set options.snapshot here. We want to read
    the latest committed data.
  */

  const bool all_parts_used = (user_defined_key_parts == kd.get_key_parts());

  /*
    This iterator seems expensive since we need to allocate and free
    memory for each unique index.

    If this needs to be optimized, for keys without NULL fields, the
    extended primary key fields can be migrated to the value portion of the
    key. This enables using Get() instead of Seek() as in the primary key
    case.

    The bloom filter may need to be disabled for this lookup.
  */
  const bool total_order_seek = !can_use_bloom_filter(
      ha_thd(), kd, new_slice, all_parts_used,
      is_ascending(*m_key_descr_arr[key_id], HA_READ_KEY_EXACT));
  const bool fill_cache = !THDVAR(ha_thd(), skip_fill_cache);

  /*
    psergey-todo: we just need to take lock, lookups not needed:
  */
  std::string dummy_value;
  const rocksdb::Status s =
      get_for_update(row_info.tx, kd.get_cf(), new_slice, &dummy_value);
  if (!s.ok() && !s.IsNotFound()) {
    return row_info.tx->set_status_error(table->in_use, s, kd, m_tbl_def);
  }

  rocksdb::Iterator *const iter = row_info.tx->get_iterator(
      kd.get_cf(), total_order_seek, fill_cache, true /* read current data */,
      false /* acquire snapshot */);
  /*
    Need to scan the transaction to see if there is a duplicate key.
    Also need to scan RocksDB and verify the key has not been deleted
    in the transaction.
  */
  iter->Seek(new_slice);
  *found = !read_key_exact(kd, iter, all_parts_used, new_slice);
  delete iter;

  return HA_EXIT_SUCCESS;
}

int ha_rocksdb::check_uniqueness_and_lock(
    const struct update_row_info &row_info, bool *const pk_changed) {
  /*
    Go through each index and determine if the index has uniqueness
    requirements. If it does, then try to obtain a row lock on the new values.
    Once all locks have been obtained, then perform the changes needed to
    update/insert the row.
  */
  for (uint key_id = 0; key_id < m_tbl_def->m_key_count; key_id++) {
    bool found;
    int rc;

    if (is_pk(key_id, table, m_tbl_def)) {
      rc = check_and_lock_unique_pk(key_id, row_info, &found, pk_changed);
    } else {
      rc = check_and_lock_sk(key_id, row_info, &found);
    }

    if (rc != 0) {
      return rc;
    }

    if (found) {
      /* There is a row with this key already, so error out. */
      errkey = key_id;
      m_dupp_errkey = errkey;
      return HA_ERR_FOUND_DUPP_KEY;
    }
  }

  return HA_EXIT_SUCCESS;
}

int ha_rocksdb::check_duplicate_sk(const TABLE *table_arg,
                                   const Rdb_key_def &index,
                                   const rocksdb::Slice *key,
                                   struct unique_sk_buf_info *sk_info) {
  uint n_null_fields = 0;
  const rocksdb::Comparator *index_comp = index.get_cf()->GetComparator();

  /* Get proper SK buffer. */
  uchar *sk_buf = sk_info->swap_and_get_sk_buf();

  /* Get memcmp form of sk without extended pk tail */
  uint sk_memcmp_size =
      index.get_memcmp_sk_parts(table_arg, *key, sk_buf, &n_null_fields);

  sk_info->sk_memcmp_key =
      rocksdb::Slice(reinterpret_cast<char *>(sk_buf), sk_memcmp_size);

  if (sk_info->sk_memcmp_key_old.size() > 0 && n_null_fields == 0 &&
      index_comp->Compare(sk_info->sk_memcmp_key, sk_info->sk_memcmp_key_old) ==
          0) {
    return 1;
  }

  sk_info->sk_memcmp_key_old = sk_info->sk_memcmp_key;
  return 0;
}

int ha_rocksdb::bulk_load_key(Rdb_transaction *const tx, const Rdb_key_def &kd,
                              const rocksdb::Slice &key,
                              const rocksdb::Slice &value) {
  rocksdb::ColumnFamilyHandle *const cf = kd.get_cf();
  DBUG_ASSERT(cf != nullptr);

  if (m_sst_info == nullptr) {
    m_sst_info = std::make_shared<Rdb_sst_info>(
        rdb, m_table_handler->m_table_name, kd.get_name(), cf,
        rocksdb_db_options, THDVAR(ha_thd(), trace_sst_api));
    tx->start_bulk_load(this);
    m_bulk_load_tx = tx;
  }

  DBUG_ASSERT(m_sst_info != nullptr);

  int rc = m_sst_info->put(key, value);
  if (rc != 0) {
    my_printf_error(ER_UNKNOWN_ERROR,
                    "Failed to add a key to sst file writer(%s)", MYF(0),
                    m_sst_info->error_message().c_str());
    rc = HA_ERR_INTERNAL_ERROR;
  }

  return rc;
}

int ha_rocksdb::finalize_bulk_load() {
  int rc = 0;

  /* Skip if there are no possible ongoing bulk loads */
  if (m_sst_info == nullptr && m_bulk_load_tx == nullptr) {
    return rc;
  }

  mysql_mutex_lock(&m_bulk_load_mutex);

  /*
    We need this check because it's possible that m_sst_info has been
    flushed and cleared by another thread by the time the mutex has been
    acquired.
  */
  if (m_sst_info != nullptr) {
    rc = m_sst_info->commit();
    if (rc != 0) {
      my_printf_error(ER_UNKNOWN_ERROR,
                      "Failed to commit bulk loaded sst file to the "
                      "data store (%s)",
                      MYF(0), m_sst_info->error_message().c_str());
      rc = HA_ERR_INTERNAL_ERROR;
    }

    m_sst_info = nullptr;
    m_bulk_load_tx->end_bulk_load(this);
    m_bulk_load_tx = nullptr;
  }

  mysql_mutex_unlock(&m_bulk_load_mutex);
  return rc;
}

int ha_rocksdb::update_pk(const Rdb_key_def &kd,
                          const struct update_row_info &row_info,
                          const bool &pk_changed) {
  const uint key_id = kd.get_keyno();
  const bool hidden_pk = is_hidden_pk(key_id, table, m_tbl_def);
  if (!hidden_pk && pk_changed) {
    /*
      The old key needs to be deleted.
    */
    const rocksdb::Status s = delete_or_singledelete(
        key_id, row_info.tx, kd.get_cf(), row_info.old_pk_slice);
    if (!s.ok()) {
      return row_info.tx->set_status_error(table->in_use, s, kd, m_tbl_def);
    }
  }

  if (table->next_number_field) {
    update_auto_incr_val();
  }

  rocksdb::Slice value_slice;
  convert_record_to_storage_format(row_info.new_pk_slice,
                                   row_info.new_pk_unpack_info, &value_slice);

  int rc = 0;
  const auto cf = m_pk_descr->get_cf();
  if (rocksdb_enable_bulk_load_api && THDVAR(table->in_use, bulk_load) &&
      !hidden_pk) {
    /*
      Write the primary key directly to an SST file using an SstFileWriter
     */
    rc = bulk_load_key(row_info.tx, kd, row_info.new_pk_slice, value_slice);
  } else if (row_info.skip_unique_check) {
    /*
      It is responsibility of the user to make sure that the data being
      inserted doesn't violate any unique keys.
    */
    row_info.tx->get_blind_write_batch()->Put(cf, row_info.new_pk_slice,
                                              value_slice);
  } else if (row_info.tx->m_ddl_transaction) {
    /*
      DDL statement must check for unique key conflicts. For example:
      ALTER TABLE tbl DROP PRIMARY KEY, ADD PRIMARY KEY(non_unique_column)
    */
    row_info.tx->get_indexed_write_batch()->Put(cf, row_info.new_pk_slice,
                                                value_slice);
  } else {
    const auto s = row_info.tx->put(cf, row_info.new_pk_slice, value_slice);
    if (!s.ok()) {
      if (s.IsBusy()) {
        errkey = table->s->primary_key;
        m_dupp_errkey = errkey;
        rc = HA_ERR_FOUND_DUPP_KEY;
      } else {
        rc = row_info.tx->set_status_error(table->in_use, s, *m_pk_descr,
                                           m_tbl_def);
      }
    }
  }

  return rc;
}

int ha_rocksdb::update_sk(const TABLE *const table_arg, const Rdb_key_def &kd,
                          const struct update_row_info &row_info) {
  int new_packed_size;
  int old_packed_size;

  rocksdb::Slice new_key_slice;
  rocksdb::Slice new_value_slice;
  rocksdb::Slice old_key_slice;

  const uint key_id = kd.get_keyno();
  /*
    Can skip updating this key if none of the key fields have changed.
  */
  if (row_info.old_data != nullptr && !m_update_scope.is_set(key_id)) {
    return HA_EXIT_SUCCESS;
  }

  const bool store_row_debug_checksums = should_store_row_debug_checksums();

  new_packed_size = kd.pack_record(
      table_arg, m_pack_buffer, row_info.new_data, m_sk_packed_tuple,
      &m_sk_tails, store_row_debug_checksums, row_info.hidden_pk_id);

  if (row_info.old_data != nullptr) {
    // The old value
    old_packed_size = kd.pack_record(
        table_arg, m_pack_buffer, row_info.old_data, m_sk_packed_tuple_old,
        &m_sk_tails_old, store_row_debug_checksums, row_info.hidden_pk_id);

    /*
      Check if we are going to write the same value. This can happen when
      one does
        UPDATE tbl SET col='foo'
      and we are looking at the row that already has col='foo'.

      We also need to compare the unpack info. Suppose, the collation is
      case-insensitive, and unpack info contains information about whether
      the letters were uppercase and lowercase.  Then, both 'foo' and 'FOO'
      will have the same key value, but different data in unpack_info.

      (note: anyone changing bytewise_compare should take this code into
      account)
    */
    if (old_packed_size == new_packed_size &&
        m_sk_tails_old.get_current_pos() == m_sk_tails.get_current_pos() &&
        memcmp(m_sk_packed_tuple_old, m_sk_packed_tuple, old_packed_size) ==
            0 &&
        memcmp(m_sk_tails_old.ptr(), m_sk_tails.ptr(),
               m_sk_tails.get_current_pos()) == 0) {
      return HA_EXIT_SUCCESS;
    }

    /*
      Deleting entries from secondary index should skip locking, but
      be visible to the transaction.
      (also note that DDL statements do not delete rows, so this is not a DDL
       statement)
    */
    old_key_slice = rocksdb::Slice(
        reinterpret_cast<const char *>(m_sk_packed_tuple_old), old_packed_size);

    row_info.tx->get_indexed_write_batch()->SingleDelete(kd.get_cf(),
                                                         old_key_slice);
  }

  /*
    We're writing a new entry for secondary key. We can skip locking; we
    should write to
    - WriteBatchWithIndex normally (so that transaction sees the new row)
    - non-indexed WriteBatch, when we don't need to see the new row:
       = when doing a DDL operation and writing to a non-unique index, or
       = when doing a bulk load
  */
  rocksdb::WriteBatchBase *write_batch;
  if ((row_info.tx->m_ddl_transaction &&
       !(table_arg->key_info[key_id].flags & HA_NOSAME)) ||
      row_info.skip_unique_check) {
    write_batch = row_info.tx->get_blind_write_batch();
  } else {
    write_batch = row_info.tx->get_indexed_write_batch();
  }

  new_key_slice = rocksdb::Slice(
      reinterpret_cast<const char *>(m_sk_packed_tuple), new_packed_size);
  new_value_slice =
      rocksdb::Slice(reinterpret_cast<const char *>(m_sk_tails.ptr()),
                     m_sk_tails.get_current_pos());

  write_batch->Put(kd.get_cf(), new_key_slice, new_value_slice);

  return HA_EXIT_SUCCESS;
}

int ha_rocksdb::update_indexes(const struct update_row_info &row_info,
                               const bool &pk_changed) {
  int rc;

  for (uint key_id = 0; key_id < m_tbl_def->m_key_count; key_id++) {
    const Rdb_key_def &kd = *m_key_descr_arr[key_id];
    if (is_pk(key_id, table, m_tbl_def)) {
      rc = update_pk(kd, row_info, pk_changed);
    } else {
      rc = update_sk(table, kd, row_info);
    }

    if (rc != 0) {
      return rc;
    }
  }

  return HA_EXIT_SUCCESS;
}

int ha_rocksdb::update_write_row(const uchar *const old_data,
                                 const uchar *const new_data,
                                 const bool skip_unique_check) {
  DBUG_ENTER_FUNC();

  bool pk_changed = false;
  struct update_row_info row_info;

  row_info.old_data = old_data;
  row_info.new_data = new_data;
  row_info.skip_unique_check = skip_unique_check;
  row_info.new_pk_unpack_info = nullptr;

  set_last_rowkey(old_data);

  row_info.tx = get_or_create_tx(table->in_use);

  if (old_data != nullptr) {
    row_info.old_pk_slice =
        rocksdb::Slice(m_last_rowkey.ptr(), m_last_rowkey.length());

    /* Determine which indexes need updating. */
    calc_updated_indexes();
  }

  /*
    Get the new row key into row_info.new_pk_slice
   */
  int rc = get_pk_for_update(&row_info);
  if (rc != 0) {
    DBUG_RETURN(rc);
  }

  if (!skip_unique_check) {
    /*
      Check to see if we are going to have failures because of unique
      keys.  Also lock the appropriate key values.
    */
    rc = check_uniqueness_and_lock(row_info, &pk_changed);
    if (rc != 0) {
      DBUG_RETURN(rc);
    }
  }

  DEBUG_SYNC(ha_thd(), "rocksdb.update_write_row_after_unique_check");

  /*
    At this point, all locks have been obtained, and all checks for duplicate
    keys have been performed. No further errors can be allowed to occur from
    here because updates to the transaction will be made and those updates
    cannot be easily removed without rolling back the entire transaction.
  */
  rc = update_indexes(row_info, pk_changed);
  if (rc != 0) {
    DBUG_RETURN(rc);
  }

  if (do_bulk_commit(row_info.tx)) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/*
  Open a cursor and position it at the passed record
*/

void ha_rocksdb::setup_scan_iterator(const Rdb_key_def &kd,
                                     rocksdb::Slice *const slice,
                                     const bool use_all_keys,
                                     const bool is_ascending,
                                     const uint eq_cond_len) {
  DBUG_ASSERT(slice != nullptr);
  DBUG_ASSERT(slice->size() >= eq_cond_len);

  Rdb_transaction *const tx = get_or_create_tx(table->in_use);

  bool skip_bloom = true;

  const rocksdb::Slice eq_cond(slice->data(), eq_cond_len);
  if (can_use_bloom_filter(ha_thd(), kd, eq_cond, use_all_keys, is_ascending)) {
    skip_bloom = false;
  }

  /*
    In some cases, setup_scan_iterator() is called multiple times from
    the same query but bloom filter can not always be used.
    Suppose the following query example. id2 is VARCHAR(30) and PRIMARY KEY
    (id1, id2).
     select count(*) from t2 WHERE id1=100 and id2 IN ('00000000000000000000',
    '100');
    In this case, setup_scan_iterator() is called twice, the first time is for
    (id1, id2)=(100, '00000000000000000000') and the second time is for (100,
    '100').
    If prefix bloom filter length is 24 bytes, prefix bloom filter can be used
    for the
    first condition but not for the second condition.
    If bloom filter condition is changed, currently it is necessary to destroy
    and
    re-create Iterator.
  */
  if (m_scan_it_skips_bloom != skip_bloom) {
    release_scan_iterator();
  }

  /*
    SQL layer can call rnd_init() multiple times in a row.
    In that case, re-use the iterator, but re-position it at the table start.
  */
  if (!m_scan_it) {
    const bool fill_cache = !THDVAR(ha_thd(), skip_fill_cache);
    if (commit_in_the_middle()) {
      DBUG_ASSERT(m_scan_it_snapshot == nullptr);
      m_scan_it_snapshot = rdb->GetSnapshot();

      auto read_opts = rocksdb::ReadOptions();
      read_opts.total_order_seek = true; // TODO: set based on WHERE conditions
      read_opts.snapshot = m_scan_it_snapshot;
      m_scan_it = rdb->NewIterator(read_opts, kd.get_cf());
    } else {
      m_scan_it = tx->get_iterator(kd.get_cf(), skip_bloom, fill_cache);
    }
    m_scan_it_skips_bloom = skip_bloom;
  }
  /*
    Seek() will "Position at the first key in the source that at or past
    target".
    The operation cannot fail.
  */
  m_scan_it->Seek(*slice);
}

void ha_rocksdb::release_scan_iterator() {
  delete m_scan_it;
  m_scan_it = nullptr;

  if (m_scan_it_snapshot) {
    rdb->ReleaseSnapshot(m_scan_it_snapshot);
    m_scan_it_snapshot = nullptr;
  }
}

void ha_rocksdb::setup_iterator_for_rnd_scan() {
  uint key_size;

  if (m_pk_descr->m_is_reverse_cf)
    m_pk_descr->get_supremum_key(m_pk_packed_tuple, &key_size);
  else
    m_pk_descr->get_infimum_key(m_pk_packed_tuple, &key_size);

  rocksdb::Slice table_key((const char *)m_pk_packed_tuple, key_size);

  setup_scan_iterator(*m_pk_descr, &table_key);
  m_skip_scan_it_next_call = true;
}

int ha_rocksdb::rnd_init(bool scan) {
  DBUG_ENTER_FUNC();

  Rdb_transaction *const tx = get_or_create_tx(table->in_use);
  setup_read_decoders();

  if (scan) {
    m_rnd_scan_is_new_snapshot = !tx->has_snapshot();
    setup_iterator_for_rnd_scan();
  } else {
    /* We don't need any preparations for rnd_pos() calls. */
  }

  // If m_lock_rows is on then we will be doing a get_for_update when accessing
  // the index, so don't acquire the snapshot right away.  Otherwise acquire
  // the snapshot immediately.
  tx->acquire_snapshot(m_lock_rows == RDB_LOCK_NONE);

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

int ha_rocksdb::rnd_next(uchar *const buf) {
  DBUG_ENTER_FUNC();

  int rc;
  ha_statistic_increment(&SSV::ha_read_rnd_next_count);
  for (;;) {
    rc = rnd_next_with_direction(buf, true);
    if (rc != HA_ERR_LOCK_DEADLOCK || !m_rnd_scan_is_new_snapshot)
      break; /* exit the loop */

    // release the snapshot and iterator and then regenerate them
    Rdb_transaction *tx = get_or_create_tx(table->in_use);
    tx->release_snapshot();
    release_scan_iterator();
    setup_iterator_for_rnd_scan();
  }

  m_rnd_scan_is_new_snapshot = false;

  if (rc == HA_ERR_KEY_NOT_FOUND)
    rc = HA_ERR_END_OF_FILE;

  DBUG_RETURN(rc);
}

/*
  See also secondary_index_read().
*/
int ha_rocksdb::rnd_next_with_direction(uchar *const buf, bool move_forward) {
  DBUG_ENTER_FUNC();

  int rc;

  table->status = STATUS_NOT_FOUND;

  if (!m_scan_it || !m_scan_it->Valid()) {
    /*
      We can get here when SQL layer has called

        h->index_init(PRIMARY);
        h->index_read_map(full index tuple, HA_READ_KEY_EXACT);

      In this case, we should return EOF.
    */
    DBUG_RETURN(HA_ERR_END_OF_FILE);
  }

  for (;;) {
    if (m_skip_scan_it_next_call) {
      m_skip_scan_it_next_call = false;
    } else {
      if (move_forward)
        m_scan_it->Next(); /* this call cannot fail */
      else
        m_scan_it->Prev(); /* this call cannot fail */
    }

    if (!m_scan_it->Valid()) {
      rc = HA_ERR_END_OF_FILE;
      break;
    }

    /* check if we're out of this table */
    const rocksdb::Slice key = m_scan_it->key();
    if (!m_pk_descr->covers_key(key)) {
      rc = HA_ERR_END_OF_FILE;
      break;
    }

    if (m_lock_rows != RDB_LOCK_NONE) {
      /*
        Lock the row we've just read.

        Now we call get_for_update which will 1) Take a lock and 2) Will fail
        if the row was deleted since the snapshot was taken.
      */
      Rdb_transaction *const tx = get_or_create_tx(table->in_use);
      DEBUG_SYNC(ha_thd(), "rocksdb_concurrent_delete");
      const rocksdb::Status s =
          get_for_update(tx, m_pk_descr->get_cf(), key, &m_retrieved_record);
      if (s.IsNotFound() &&
          my_core::thd_tx_isolation(ha_thd()) == ISO_READ_COMMITTED) {
        // This occurs if we accessed a row, tried to lock it, failed,
        // released and reacquired the snapshot (because of READ COMMITTED
        // mode) and the row was deleted by someone else in the meantime.
        // If so, we just want to move on to the next row.
        continue;
      }

      if (!s.ok()) {
        DBUG_RETURN(
            tx->set_status_error(table->in_use, s, *m_pk_descr, m_tbl_def));
      }

      // If we called get_for_update() use the value from that call not from
      // the iterator as it may be stale since we don't have a snapshot
      // when m_lock_rows is not RDB_LOCK_NONE.
      m_last_rowkey.copy(key.data(), key.size(), &my_charset_bin);
      rc = convert_record_from_storage_format(&key, buf);
    } else {
      // Use the value from the iterator
      rocksdb::Slice value = m_scan_it->value();
      m_last_rowkey.copy(key.data(), key.size(), &my_charset_bin);
      rc = convert_record_from_storage_format(&key, &value, buf);
    }

    table->status = 0;
    break;
  }

  if (!rc) {
    update_row_stats(ROWS_READ);
  }

  DBUG_RETURN(rc);
}

int ha_rocksdb::rnd_end() {
  DBUG_ENTER_FUNC();

  release_scan_iterator();

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

int ha_rocksdb::index_init(uint idx, bool sorted) {
  DBUG_ENTER_FUNC();

  Rdb_transaction *const tx = get_or_create_tx(table->in_use);
  DBUG_ASSERT(tx != nullptr);

  setup_read_decoders();

  // If m_lock_rows is not RDB_LOCK_NONE then we will be doing a get_for_update
  // when accessing the index, so don't acquire the snapshot right away.
  // Otherwise acquire the snapshot immediately.
  tx->acquire_snapshot(m_lock_rows == RDB_LOCK_NONE);

  active_index = idx;

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

int ha_rocksdb::index_end() {
  DBUG_ENTER_FUNC();

  release_scan_iterator();

  active_index = MAX_KEY;
  in_range_check_pushed_down = FALSE;

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

int ha_rocksdb::truncate() {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(m_tbl_def != nullptr);

  m_tbl_def->m_auto_incr_val = 1;
  m_tbl_def->m_hidden_pk_val = 1;

  remove_rows(m_tbl_def);

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/*
  Delete the row we've last read. The row is also passed as parameter.

  @detail
    The caller guarantees table buf points to the row that was just read.
    The row is either table->record[0] or table->record[1].
    (Check out InnoDB: row_update_for_mysql() has "UT_NOT_USED(mysql_rec)"
*/
int ha_rocksdb::delete_row(const uchar *const buf) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(buf != nullptr);

  ha_statistic_increment(&SSV::ha_delete_count);
  set_last_rowkey(buf);

  rocksdb::Slice key_slice(m_last_rowkey.ptr(), m_last_rowkey.length());
  Rdb_transaction *const tx = get_or_create_tx(table->in_use);

  const uint index = pk_index(table, m_tbl_def);
  rocksdb::Status s =
      delete_or_singledelete(index, tx, m_pk_descr->get_cf(), key_slice);
  if (!s.ok()) {
    DBUG_RETURN(tx->set_status_error(table->in_use, s, *m_pk_descr, m_tbl_def));
  }

  longlong hidden_pk_id = 0;
  if (m_tbl_def->m_key_count > 1 && has_hidden_pk(table) &&
      read_hidden_pk_id_from_rowkey(&hidden_pk_id))
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);

  // Delete the record for every secondary index
  for (uint i = 0; i < m_tbl_def->m_key_count; i++) {
    if (!is_pk(i, table, m_tbl_def)) {
      int packed_size;
      const Rdb_key_def &kd = *m_key_descr_arr[i];
      packed_size = kd.pack_record(table, m_pack_buffer, buf, m_sk_packed_tuple,
                                   nullptr, false, hidden_pk_id);
      rocksdb::Slice secondary_key_slice(
          reinterpret_cast<const char *>(m_sk_packed_tuple), packed_size);
      /* Deleting on secondary key doesn't need any locks: */
      tx->get_indexed_write_batch()->SingleDelete(kd.get_cf(),
                                                  secondary_key_slice);
    }
  }

  if (do_bulk_commit(tx)) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }
  update_row_stats(ROWS_DELETED);

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

rocksdb::Status ha_rocksdb::delete_or_singledelete(
    uint index, Rdb_transaction *const tx,
    rocksdb::ColumnFamilyHandle *const column_family,
    const rocksdb::Slice &key) {
  if (can_use_single_delete(index))
    return tx->single_delete(column_family, key);
  return tx->delete_key(column_family, key);
}

void ha_rocksdb::update_stats(void) {
  DBUG_ENTER_FUNC();

  stats.records = 0;
  stats.index_file_length = 0ul;
  stats.data_file_length = 0ul;
  stats.mean_rec_length = 0;

  for (uint i = 0; i < m_tbl_def->m_key_count; i++) {
    if (is_pk(i, table, m_tbl_def)) {
      stats.data_file_length = m_pk_descr->m_stats.m_actual_disk_size;
      stats.records = m_pk_descr->m_stats.m_rows;
    } else {
      stats.index_file_length += m_key_descr_arr[i]->m_stats.m_actual_disk_size;
    }
  }

  DBUG_VOID_RETURN;
}

int ha_rocksdb::info(uint flag) {
  DBUG_ENTER_FUNC();

  if (!table)
    return HA_EXIT_FAILURE;

  if (flag & HA_STATUS_VARIABLE) {
    /*
      Test only to simulate corrupted stats
    */
    DBUG_EXECUTE_IF("myrocks_simulate_negative_stats",
                    m_pk_descr->m_stats.m_actual_disk_size =
                        -m_pk_descr->m_stats.m_actual_disk_size;);

    update_stats();

    /*
      If any stats are negative due to bad cached stats, re-run analyze table
      and re-retrieve the stats.
    */
    if (static_cast<longlong>(stats.data_file_length) < 0 ||
        static_cast<longlong>(stats.index_file_length) < 0 ||
        static_cast<longlong>(stats.records) < 0) {
      if (analyze(nullptr, nullptr)) {
        DBUG_RETURN(HA_EXIT_FAILURE);
      }

      update_stats();
    }

    if (stats.records == 0) {
      // most likely, the table is in memtable
      // try to deduce from GetApproximateSizes
      uchar buf[Rdb_key_def::INDEX_NUMBER_SIZE * 2];
      auto r = get_range(pk_index(table, m_tbl_def), buf);
      uint64_t sz = 0;

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
      rdb->GetApproximateSizes(m_pk_descr->get_cf(), &r, 1, &sz, true);
#pragma GCC diagnostic pop

      stats.records = sz / ROCKSDB_ASSUMED_KEY_VALUE_DISK_SIZE;
      stats.data_file_length = sz;

      if (rocksdb_debug_optimizer_n_rows > 0)
        stats.records = rocksdb_debug_optimizer_n_rows;
    }

    if (stats.records != 0)
      stats.mean_rec_length = stats.data_file_length / stats.records;
  }
  if (flag & HA_STATUS_CONST) {
    ref_length = m_pk_descr->max_storage_fmt_length();

    // TODO: Needs to reimplement after having real index statistics
    for (uint i = 0; i < m_tbl_def->m_key_count; i++) {
      if (is_hidden_pk(i, table, m_tbl_def)) {
        continue;
      }
      KEY *const k = &table->key_info[i];
      for (uint j = 0; j < k->actual_key_parts; j++) {
        const Rdb_index_stats &k_stats = m_key_descr_arr[i]->m_stats;
        uint x = k_stats.m_distinct_keys_per_prefix.size() > j &&
                         k_stats.m_distinct_keys_per_prefix[j] > 0
                     ? k_stats.m_rows / k_stats.m_distinct_keys_per_prefix[j]
                     : 0;
        if (x > stats.records)
          x = stats.records;
        if ((x == 0 && rocksdb_debug_optimizer_no_zero_cardinality) ||
            rocksdb_debug_optimizer_n_rows > 0) {
          // Fake cardinality implementation. For example, (idx1, idx2, idx3)
          // index
          // will have rec_per_key for (idx1)=4, (idx1,2)=2, and (idx1,2,3)=1.
          // rec_per_key for the whole index is 1, and multiplied by 2^n if
          // n suffix columns of the index are not used.
          x = 1 << (k->actual_key_parts - j - 1);
        }
        k->rec_per_key[j] = x;
      }
    }
  }

  if (flag & HA_STATUS_ERRKEY) {
    /*
      Currently we support only primary keys so we know which key had a
      uniqueness violation.
    */
    errkey = m_dupp_errkey;
    dup_ref = m_pk_tuple; // TODO(?): this should store packed PK.
  }

  if (flag & HA_STATUS_AUTO) {
    stats.auto_increment_value = m_tbl_def->m_auto_incr_val;
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

void ha_rocksdb::position(const uchar *const record) {
  DBUG_ENTER_FUNC();

  longlong hidden_pk_id = 0;
  if (has_hidden_pk(table) && read_hidden_pk_id_from_rowkey(&hidden_pk_id))
    DBUG_ASSERT(false); // should never reach here

  /*
    Get packed primary key value from the record.

    (Note: m_last_rowkey has the packed PK of last-read-row, which allows to
    handle most cases, but there is an exception to this: when slave applies
    RBR events, it fills the record and then calls position(); rnd_pos())

    Also note that we *can* rely on PK column values being available. This is
    because table_flags() includes HA_PRIMARY_KEY_REQUIRED_FOR_POSITION bit.
    When that is true, table->prepare_for_position() adds PK columns into the
    read set (this may potentially disable index-only access when PK column
    cannot be restored from its mem-comparable form in the secondary indexes).
  */
  const uint packed_size = m_pk_descr->pack_record(
      table, m_pack_buffer, record, ref, nullptr, false, hidden_pk_id);

  /*
    It could be that mem-comparable form of PK occupies less than ref_length
    bytes. Fill the remainder with zeros.
  */
  if (ref_length > packed_size)
    memset(ref + packed_size, 0, ref_length - packed_size);

  DBUG_VOID_RETURN;
}

int ha_rocksdb::rnd_pos(uchar *const buf, uchar *const pos) {
  DBUG_ENTER_FUNC();

  int rc;
  size_t len;

  ha_statistic_increment(&SSV::ha_read_rnd_count);
  len = m_pk_descr->key_length(table,
                               rocksdb::Slice((const char *)pos, ref_length));
  if (len == size_t(-1)) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR); /* Data corruption? */
  }

  rc = get_row_by_rowid(buf, pos, len);

  if (!rc) {
    update_row_stats(ROWS_READ);
  }

  DBUG_RETURN(rc);
}

/*
  @brief
    Calculate (if needed) the bitmap of indexes that are modified by the
    current query

  @detail
    The calculation done by checking index definitions against the
  table->write_set
    column bitmap.
*/

void ha_rocksdb::calc_updated_indexes() {
  if (!m_update_scope_is_valid) {
    m_update_scope_is_valid = true;
    m_update_scope.clear_all();

    for (uint keynr = 0; keynr < table->s->keys; keynr++) {
      const Rdb_key_def &kd = *m_key_descr_arr[keynr];
      /* Walk over all key parts, including the "extended key" suffix */
      const uint key_parts = kd.get_key_parts();
      for (uint kp = 0; kp < key_parts; kp++) {
        if (has_hidden_pk(table) && kp + 1 == key_parts)
          break;

        Field *const field = kd.get_table_field_for_part_no(table, kp);
        if (bitmap_is_set(table->write_set, field->field_index)) {
          m_update_scope.set_bit(keynr);
          break;
        }
      }
    }
  }
}

int ha_rocksdb::update_row(const uchar *const old_data, uchar *const new_data) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(old_data != nullptr);
  DBUG_ASSERT(new_data != nullptr);
  DBUG_ASSERT(m_lock_rows == RDB_LOCK_WRITE);
  /*
    old_data points to record we're updating. It is the same as the record
    we've just read (for multi-table UPDATE, too, because SQL layer will make
    an rnd_pos() call to re-read the record before calling update_row())
  */
  DBUG_ASSERT(new_data == table->record[0]);

  ha_statistic_increment(&SSV::ha_update_count);
  const int rv = update_write_row(old_data, new_data, false);

  if (rv == 0) {
    update_row_stats(ROWS_UPDATED);
  }

  DBUG_RETURN(rv);
}

/* The following function was copied from ha_blackhole::store_lock: */
THR_LOCK_DATA **ha_rocksdb::store_lock(THD *const thd, THR_LOCK_DATA **to,
                                       enum thr_lock_type lock_type) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(thd != nullptr);
  DBUG_ASSERT(to != nullptr);

  bool in_lock_tables = my_core::thd_in_lock_tables(thd);

  /* First, make a decision about MyRocks's internal locking */
  if (lock_type >= TL_WRITE_ALLOW_WRITE) {
    m_lock_rows = RDB_LOCK_WRITE;
  } else if (lock_type == TL_READ_WITH_SHARED_LOCKS) {
    m_lock_rows = RDB_LOCK_READ;
  } else {
    m_lock_rows = RDB_LOCK_NONE;
    if (THDVAR(thd, lock_scanned_rows)) {
      /*
        The following logic was copied directly from
        ha_innobase::store_lock_with_x_type() in
        storage/innobase/handler/ha_innodb.cc and causes MyRocks to leave
        locks in place on rows that are in a table that is not being updated.
      */
      const uint sql_command = my_core::thd_sql_command(thd);
      if ((lock_type == TL_READ && in_lock_tables) ||
          (lock_type == TL_READ_HIGH_PRIORITY && in_lock_tables) ||
          lock_type == TL_READ_WITH_SHARED_LOCKS ||
          lock_type == TL_READ_NO_INSERT ||
          (lock_type != TL_IGNORE && sql_command != SQLCOM_SELECT)) {

        ulong tx_isolation = my_core::thd_tx_isolation(thd);
        if (sql_command != SQLCOM_CHECKSUM &&
            ((my_core::thd_test_options(thd, OPTION_BIN_LOG) &&
              tx_isolation > ISO_READ_COMMITTED) ||
             tx_isolation == ISO_SERIALIZABLE ||
             (lock_type != TL_READ && lock_type != TL_READ_NO_INSERT) ||
             (sql_command != SQLCOM_INSERT_SELECT &&
              sql_command != SQLCOM_REPLACE_SELECT &&
              sql_command != SQLCOM_UPDATE && sql_command != SQLCOM_DELETE &&
              sql_command != SQLCOM_CREATE_TABLE))) {
          m_lock_rows = RDB_LOCK_READ;
        }
      }
    }
  }

  /* Then, tell the SQL layer what kind of locking it should use: */
  if (lock_type != TL_IGNORE && m_db_lock.type == TL_UNLOCK) {
    /*
      Here is where we get into the guts of a row level lock.
      If TL_UNLOCK is set
      If we are not doing a LOCK TABLE or DISCARD/IMPORT
      TABLESPACE, then allow multiple writers
    */

    if ((lock_type >= TL_WRITE_CONCURRENT_INSERT && lock_type <= TL_WRITE) &&
        !in_lock_tables && !my_core::thd_tablespace_op(thd)) {
      lock_type = TL_WRITE_ALLOW_WRITE;
    }

    /*
      In queries of type INSERT INTO t1 SELECT ... FROM t2 ...
      MySQL would use the lock TL_READ_NO_INSERT on t2, and that
      would conflict with TL_WRITE_ALLOW_WRITE, blocking all inserts
      to t2. Convert the lock to a normal read lock to allow
      concurrent inserts to t2.
    */

    if (lock_type == TL_READ_NO_INSERT && !in_lock_tables) {
      lock_type = TL_READ;
    }

    m_db_lock.type = lock_type;
  }

  *to++ = &m_db_lock;

  DBUG_RETURN(to);
}

void ha_rocksdb::read_thd_vars(THD *const thd) {
  m_store_row_debug_checksums = THDVAR(thd, store_row_debug_checksums);
  m_verify_row_debug_checksums = THDVAR(thd, verify_row_debug_checksums);
  m_checksums_pct = THDVAR(thd, checksums_pct);
}

const char *ha_rocksdb::thd_rocksdb_tmpdir() {
  const char *tmp_dir = THDVAR(ha_thd(), tmpdir);

  /*
    We want to treat an empty string as nullptr, in these cases DDL operations
    will use the default --tmpdir passed to mysql instead.
  */
  if (tmp_dir != nullptr && *tmp_dir == '\0') {
    tmp_dir = nullptr;
  }

  return (tmp_dir);
}

int ha_rocksdb::external_lock(THD *const thd, int lock_type) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(thd != nullptr);

  int res = 0;
  int binlog_format = my_core::thd_binlog_format(thd);
  bool unsafe_for_binlog = THDVAR(ha_thd(), unsafe_for_binlog);
  if (lock_type == F_WRLCK && !thd->rli_slave && !unsafe_for_binlog &&
      binlog_format != BINLOG_FORMAT_ROW &&
      binlog_format != BINLOG_FORMAT_UNSPEC &&
      my_core::thd_binlog_filter_ok(thd)) {
    my_printf_error(
        ER_UNKNOWN_ERROR,
        "Can't execute updates on master with binlog_format != ROW.", MYF(0));
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  if (lock_type == F_UNLCK) {
    Rdb_transaction *const tx = get_or_create_tx(thd);

    tx->io_perf_end_and_record(&m_io_perf);
    if (!my_core::thd_test_options(thd, OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN)) {
      /*
        Do like InnoDB: when we get here, it's time to commit a
        single-statement transaction.

        If the statement involved multiple tables, this code will be executed
        for each of them, but that's ok because non-first tx->commit() calls
        will be no-ops.
      */
      res = tx->commit_or_rollback();
    }
  } else {
    if (my_core::thd_tx_isolation(thd) < ISO_READ_COMMITTED ||
        my_core::thd_tx_isolation(thd) > ISO_REPEATABLE_READ) {
      my_printf_error(
          ER_UNKNOWN_ERROR, "MyRocks supports only READ COMMITTED and "
                            "REPEATABLE READ isolation levels. "
                            "Please change from current isolation "
                            "level %s",
          MYF(0), tx_isolation_names[my_core::thd_tx_isolation(thd)]);
      DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
    }
    /*
      It's nice to do the following on start of every statement. The problem
      is, handler->start_stmt() is not called for INSERTs.
      So, we put this code here.
    */
    Rdb_transaction *const tx = get_or_create_tx(thd);
    read_thd_vars(thd);

    m_update_scope_is_valid = false;

    if (skip_unique_check()) {
      if ((thd->lex->sql_command == SQLCOM_INSERT ||
           thd->lex->sql_command == SQLCOM_LOAD ||
           thd->lex->sql_command == SQLCOM_REPLACE) &&
          (thd->lex->duplicates == DUP_REPLACE ||
           thd->lex->duplicates == DUP_UPDATE)) {
        my_printf_error(ER_UNKNOWN_ERROR,
                        "When unique checking is disabled in MyRocks, INSERT,"
                        "UPDATE,LOAD statements with clauses that update or "
                        "replace the key (i.e. "
                        "INSERT ON DUPLICATE KEY UPDATE, REPLACE) are not "
                        "allowed. Query: %s",
                        MYF(0), thd->query());
        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
      }
    }

    if (lock_type == F_WRLCK) {
      if (tx->is_tx_read_only()) {
        my_printf_error(ER_UNKNOWN_ERROR,
                        "Can't execute updates when you started a transaction "
                        "with START TRANSACTION WITH CONSISTENT SNAPSHOT.",
                        MYF(0));
        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
      }

      /*
        SQL layer signals us to take a write lock. It does so when starting DML
        statement. We should put locks on the rows we're reading.

        Note: sometimes, external_lock() can be called without a prior
        ::store_lock call.  That's why we need to set lock_* members here, too.
      */
      m_lock_rows = RDB_LOCK_WRITE;

      if (thd->lex->sql_command == SQLCOM_CREATE_INDEX ||
          thd->lex->sql_command == SQLCOM_DROP_INDEX ||
          thd->lex->sql_command == SQLCOM_ALTER_TABLE) {
        tx->m_ddl_transaction = true;
      }
    }
    rocksdb_register_tx(rocksdb_hton, thd, tx);
    tx->io_perf_start(&m_io_perf);
  }

  DBUG_RETURN(res);
}

/**
  @note
  A quote from ha_innobase::start_stmt():
  <quote>
  MySQL calls this function at the start of each SQL statement inside LOCK
  TABLES. Inside LOCK TABLES the ::external_lock method does not work to
  mark SQL statement borders.
  </quote>
*/

int ha_rocksdb::start_stmt(THD *const thd, thr_lock_type lock_type) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(thd != nullptr);

  Rdb_transaction *const tx = get_or_create_tx(thd);
  read_thd_vars(thd);
  rocksdb_register_tx(ht, thd, tx);
  tx->io_perf_start(&m_io_perf);

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

rocksdb::Range get_range(uint32_t i,
                         uchar buf[Rdb_key_def::INDEX_NUMBER_SIZE * 2],
                         int offset1, int offset2) {
  uchar *buf_begin = buf;
  uchar *buf_end = buf + Rdb_key_def::INDEX_NUMBER_SIZE;
  rdb_netbuf_store_index(buf_begin, i + offset1);
  rdb_netbuf_store_index(buf_end, i + offset2);

  return rocksdb::Range(
      rocksdb::Slice((const char *)buf_begin, Rdb_key_def::INDEX_NUMBER_SIZE),
      rocksdb::Slice((const char *)buf_end, Rdb_key_def::INDEX_NUMBER_SIZE));
}

static rocksdb::Range get_range(const Rdb_key_def &kd,
                                uchar buf[Rdb_key_def::INDEX_NUMBER_SIZE * 2],
                                int offset1, int offset2) {
  return get_range(kd.get_index_number(), buf, offset1, offset2);
}

rocksdb::Range get_range(const Rdb_key_def &kd,
                         uchar buf[Rdb_key_def::INDEX_NUMBER_SIZE * 2]) {
  if (kd.m_is_reverse_cf) {
    return myrocks::get_range(kd, buf, 1, 0);
  } else {
    return myrocks::get_range(kd, buf, 0, 1);
  }
}

rocksdb::Range
ha_rocksdb::get_range(const int &i,
                      uchar buf[Rdb_key_def::INDEX_NUMBER_SIZE * 2]) const {
  return myrocks::get_range(*m_key_descr_arr[i], buf);
}

/*
  Drop index thread's main logic
*/

void Rdb_drop_index_thread::run() {
  mysql_mutex_lock(&m_signal_mutex);

  for (;;) {
    // The stop flag might be set by shutdown command
    // after drop_index_thread releases signal_mutex
    // (i.e. while executing expensive Seek()). To prevent drop_index_thread
    // from entering long cond_timedwait, checking if stop flag
    // is true or not is needed, with drop_index_interrupt_mutex held.
    if (m_stop) {
      break;
    }

    timespec ts;
    clock_gettime(CLOCK_REALTIME, &ts);
    ts.tv_sec += dict_manager.is_drop_index_empty()
                     ? 24 * 60 * 60 // no filtering
                     : 60;          // filtering

    const auto ret __attribute__((__unused__)) =
        mysql_cond_timedwait(&m_signal_cond, &m_signal_mutex, &ts);
    if (m_stop) {
      break;
    }
    // make sure, no program error is returned
    DBUG_ASSERT(ret == 0 || ret == ETIMEDOUT);
    mysql_mutex_unlock(&m_signal_mutex);

    std::unordered_set<GL_INDEX_ID> indices;
    dict_manager.get_ongoing_drop_indexes(&indices);
    if (!indices.empty()) {
      std::unordered_set<GL_INDEX_ID> finished;
      rocksdb::ReadOptions read_opts;
      read_opts.total_order_seek = true; // disable bloom filter

      for (const auto d : indices) {
        uint32 cf_flags = 0;
        if (!dict_manager.get_cf_flags(d.cf_id, &cf_flags)) {
          sql_print_error("RocksDB: Failed to get column family flags "
                          "from cf id %u. MyRocks data dictionary may "
                          "get corrupted.",
                          d.cf_id);
          abort_with_stack_traces();
        }
        rocksdb::ColumnFamilyHandle *cfh = cf_manager.get_cf(d.cf_id);
        DBUG_ASSERT(cfh);
        const bool is_reverse_cf = cf_flags & Rdb_key_def::REVERSE_CF_FLAG;

        bool index_removed = false;
        uchar key_buf[Rdb_key_def::INDEX_NUMBER_SIZE] = {0};
        rdb_netbuf_store_uint32(key_buf, d.index_id);
        const rocksdb::Slice key =
            rocksdb::Slice((char *)key_buf, sizeof(key_buf));
        uchar buf[Rdb_key_def::INDEX_NUMBER_SIZE * 2];
        rocksdb::Range range = get_range(d.index_id, buf, is_reverse_cf ? 1 : 0,
                                         is_reverse_cf ? 0 : 1);
        rocksdb::CompactRangeOptions compact_range_options;
        compact_range_options.bottommost_level_compaction =
            rocksdb::BottommostLevelCompaction::kForce;
        compact_range_options.exclusive_manual_compaction = false;
        rocksdb::Status status = DeleteFilesInRange(rdb->GetBaseDB(), cfh,
                                                    &range.start, &range.limit);
        if (!status.ok()) {
          if (status.IsShutdownInProgress()) {
            break;
          }
          rdb_handle_io_error(status, RDB_IO_ERROR_BG_THREAD);
        }
        status = rdb->CompactRange(compact_range_options, cfh, &range.start,
                                   &range.limit);
        if (!status.ok()) {
          if (status.IsShutdownInProgress()) {
            break;
          }
          rdb_handle_io_error(status, RDB_IO_ERROR_BG_THREAD);
        }
        std::unique_ptr<rocksdb::Iterator> it(rdb->NewIterator(read_opts, cfh));
        it->Seek(key);
        if (is_reverse_cf) {
          if (!it->Valid()) {
            it->SeekToLast();
          } else {
            it->Prev();
          }
        }
        if (!it->Valid()) {
          index_removed = true;
        } else {
          if (memcmp(it->key().data(), key_buf,
                     Rdb_key_def::INDEX_NUMBER_SIZE)) {
            // Key does not have same prefix
            index_removed = true;
          }
        }
        if (index_removed) {
          finished.insert(d);
        }
      }

      if (!finished.empty()) {
        dict_manager.finish_drop_indexes(finished);
      }
    }
    mysql_mutex_lock(&m_signal_mutex);
  }

  mysql_mutex_unlock(&m_signal_mutex);
}

Rdb_tbl_def *ha_rocksdb::get_table_if_exists(const char *const tablename) {
  DBUG_ASSERT(tablename != nullptr);

  std::string str;
  if (rdb_normalize_tablename(tablename, &str)) {
    // We were not passed table name?
    DBUG_ASSERT(0);
    return nullptr;
  }

  return ddl_manager.find(str);
}

/*
  Note: the following function is called when the table is not open. That is,
  this->table==nullptr, pk_key_descr==nullptr, etc.

  tablename points to line in form "./dbname/tablename".
*/

int ha_rocksdb::delete_table(const char *const tablename) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(tablename != nullptr);

  const std::unique_ptr<rocksdb::WriteBatch> wb = dict_manager.begin();
  rocksdb::WriteBatch *const batch = wb.get();

  /* Find the table in the hash */
  Rdb_tbl_def *const tbl = get_table_if_exists(tablename);
  if (!tbl)
    DBUG_RETURN(HA_ERR_NO_SUCH_TABLE);
  dict_manager.add_drop_table(tbl->m_key_descr_arr, tbl->m_key_count, batch);

  /*
    Remove the table entry in data dictionary (this will also remove it from
    the persistent data dictionary).
  */
  ddl_manager.remove(tbl, batch, true);
  if (dict_manager.commit(batch))
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);

  rdb_drop_idx_thread.signal();

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

void ha_rocksdb::remove_rows(Rdb_tbl_def *const tbl) {
  const rocksdb::WriteOptions wo =
      rdb_get_rocksdb_write_options(handler::ha_thd());

  rocksdb::ReadOptions opts;
  opts.total_order_seek = true;
  rocksdb::Iterator *const it = rdb->NewIterator(opts);

  char key_buf[MAX_KEY_LENGTH];
  uint key_len;
  /*
    Remove all records in each index.
    (This is is not crash-safe, but it doesn't matter, because bulk row
    deletion will be handled on rocksdb side)
  */
  for (uint i = 0; i < tbl->m_key_count; i++) {
    const Rdb_key_def &kd = *tbl->m_key_descr_arr[i];
    kd.get_infimum_key(reinterpret_cast<uchar *>(key_buf), &key_len);

    const rocksdb::Slice table_key(key_buf, key_len);
    it->Seek(table_key);
    while (it->Valid()) {
      const rocksdb::Slice key = it->key();
      if (!kd.covers_key(key)) {
        break;
      }

      if (can_use_single_delete(i))
        rdb->SingleDelete(wo, key);
      else
        rdb->Delete(wo, key);
      it->Next();
    }
  }
  delete it;
}

int ha_rocksdb::rename_table(const char *const from, const char *const to) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(from != nullptr);
  DBUG_ASSERT(to != nullptr);

  bool write_err = false;
  std::string from_str;
  std::string to_str;
  std::string from_db;
  std::string to_db;

  if (rdb_normalize_tablename(from, &from_str) ||
      rdb_split_normalized_tablename(from_str, &from_db)) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  if (rdb_normalize_tablename(to, &to_str) ||
      rdb_split_normalized_tablename(to_str, &to_db)) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  // If the user changed the database part of the name then validate that the
  // 'to' database exists.
  if (from_db != to_db && !rdb_database_exists(to_db)) {
    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  /* Check if any index has a per-index column family */
  {
    /*
      We can't check this directly, because
      1. the object that referred to the old table has been close()d.
      2. this ha_rocksdb object has no connection to any table at all, it has
         been just created with (TABLE*)nullptr.

      So, we have to find the old table in the ddl_manager (it's there because
      it has been opened by this statement), and check is_auto_cf there.
    */
    Rdb_tbl_def *tdef;
    if (!(tdef = ddl_manager.find(from_str)))
      DBUG_RETURN(HA_ERR_INTERNAL_ERROR);

    for (uint i = 0; i < tdef->m_key_count; i++) {
      DBUG_ASSERT(tdef->m_key_descr_arr != nullptr);

      if (tdef->m_key_descr_arr[i]->m_is_auto_cf) {
        my_error(ER_NOT_SUPPORTED_YET, MYF(0),
                 "ALTER TABLE on table with per-index CF");
        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
      }
    }
  }

  const std::unique_ptr<rocksdb::WriteBatch> wb = dict_manager.begin();
  rocksdb::WriteBatch *const batch = wb.get();
  dict_manager.lock();
  write_err =
      ddl_manager.rename(from_str, to_str, batch) || dict_manager.commit(batch);
  dict_manager.unlock();

  DBUG_RETURN(write_err ? HA_ERR_INTERNAL_ERROR : 0);
}

/**
  check_if_incompatible_data() called if ALTER TABLE can't detect otherwise
  if new and old definition are compatible

  @details If there are no other explicit signs like changed number of
  fields this function will be called by compare_tables()
  (sql/sql_tables.cc) to decide should we rewrite whole table or only .frm
  file.

*/

bool ha_rocksdb::check_if_incompatible_data(HA_CREATE_INFO *const info,
                                            uint table_changes) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(info != nullptr);

  // this function is needed only for online alter-table
  DBUG_RETURN(COMPATIBLE_DATA_NO);
}

int ha_rocksdb::extra(enum ha_extra_function operation) {
  DBUG_ENTER_FUNC();

  switch (operation) {
  case HA_EXTRA_KEYREAD:
    m_keyread_only = true;
    break;
  case HA_EXTRA_NO_KEYREAD:
    m_keyread_only = false;
    break;
  case HA_EXTRA_FLUSH:
    /*
      If the table has blobs, then they are part of m_retrieved_record.
      This call invalidates them.
    */
    m_retrieved_record.clear();
    break;
  default:
    break;
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/*
  Given a starting key and an ending key, estimate the number of rows that
  will exist between the two keys.
*/
ha_rows ha_rocksdb::records_in_range(uint inx, key_range *const min_key,
                                     key_range *const max_key) {
  DBUG_ENTER_FUNC();

  ha_rows ret = THDVAR(ha_thd(), records_in_range);
  if (ret) {
    DBUG_RETURN(ret);
  }
  if (table->force_index) {
    const ha_rows force_rows = THDVAR(ha_thd(), force_index_records_in_range);
    if (force_rows) {
      DBUG_RETURN(force_rows);
    }
  }

  const Rdb_key_def &kd = *m_key_descr_arr[inx];

  uint size1 = 0;
  if (min_key) {
    size1 = kd.pack_index_tuple(table, m_pack_buffer, m_sk_packed_tuple,
                                min_key->key, min_key->keypart_map);
    if (min_key->flag == HA_READ_PREFIX_LAST_OR_PREV ||
        min_key->flag == HA_READ_PREFIX_LAST ||
        min_key->flag == HA_READ_AFTER_KEY) {
      kd.successor(m_sk_packed_tuple, size1);
    }
  } else {
    kd.get_infimum_key(m_sk_packed_tuple, &size1);
  }

  uint size2 = 0;
  if (max_key) {
    size2 = kd.pack_index_tuple(table, m_pack_buffer, m_sk_packed_tuple_old,
                                max_key->key, max_key->keypart_map);
    if (max_key->flag == HA_READ_PREFIX_LAST_OR_PREV ||
        max_key->flag == HA_READ_PREFIX_LAST ||
        max_key->flag == HA_READ_AFTER_KEY) {
      kd.successor(m_sk_packed_tuple_old, size2);
    }
    // pad the upper key with FFFFs to make sure it is more than the lower
    if (size1 > size2) {
      memset(m_sk_packed_tuple_old + size2, 0xff, size1 - size2);
      size2 = size1;
    }
  } else {
    kd.get_supremum_key(m_sk_packed_tuple_old, &size2);
  }

  const rocksdb::Slice slice1((const char *)m_sk_packed_tuple, size1);
  const rocksdb::Slice slice2((const char *)m_sk_packed_tuple_old, size2);

  // slice1 >= slice2 means no row will match
  if (slice1.compare(slice2) >= 0) {
    DBUG_RETURN(HA_EXIT_SUCCESS);
  }

  rocksdb::Range r(kd.m_is_reverse_cf ? slice2 : slice1,
                   kd.m_is_reverse_cf ? slice1 : slice2);

  uint64_t sz = 0;
  auto disk_size = kd.m_stats.m_actual_disk_size;
  if (disk_size == 0)
    disk_size = kd.m_stats.m_data_size;
  auto rows = kd.m_stats.m_rows;
  if (rows == 0 || disk_size == 0) {
    rows = 1;
    disk_size = ROCKSDB_ASSUMED_KEY_VALUE_DISK_SIZE;
  }

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  // Getting statistics, including from Memtables
  rdb->GetApproximateSizes(kd.get_cf(), &r, 1, &sz, true);
#pragma GCC diagnostic pop

  ret = rows * sz / disk_size;

  /*
    GetApproximateSizes() gives estimates so ret might exceed stats.records.
    MySQL then decides to use full index scan rather than range scan, which
    is not efficient for most cases.
    To prevent this, changing estimated records slightly smaller than
    stats.records.
  */
  if (ret >= stats.records) {
    ret = stats.records * 0.99;
  }

  if (rocksdb_debug_optimizer_n_rows > 0) {
    ret = rocksdb_debug_optimizer_n_rows;
  } else if (ret == 0) {
    ret = 1;
  }

  DBUG_RETURN(ret);
}

void ha_rocksdb::update_create_info(HA_CREATE_INFO *const create_info) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(create_info != nullptr);

  if (!(create_info->used_fields & HA_CREATE_USED_AUTO)) {
    create_info->auto_increment_value = m_tbl_def->m_auto_incr_val;
  }

  DBUG_VOID_RETURN;
}

/**
  @brief
  Doing manual compaction on OPTIMIZE TABLE in RocksDB.
  Compaction itself is executed by background thread in RocksDB, but
  CompactRange() waits until compaction completes so this function
  may take a long time.
  Since RocksDB dataset is allocated per index id, OPTIMIZE TABLE
  triggers manual compaction for all indexes of the table.
  @details
  Compaction range is from the beginning of the index id to
  the first row of the next index id. When using reverse order
  column family, the first row of the next index id should be
  the last row of the previous index id.
*/
int ha_rocksdb::optimize(THD *const thd, HA_CHECK_OPT *const check_opt) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(thd != nullptr);
  DBUG_ASSERT(check_opt != nullptr);

  int rc = 0;
  for (uint i = 0; i < table->s->keys; i++) {
    uchar buf[Rdb_key_def::INDEX_NUMBER_SIZE * 2];
    auto range = get_range(i, buf);
    if (!rdb->CompactRange(rocksdb::CompactRangeOptions(),
                           m_key_descr_arr[i]->get_cf(), &range.start,
                           &range.limit)
             .ok()) {
      rc = 1;
      break;
    }
  }

  DBUG_RETURN(rc);
}

int ha_rocksdb::calculate_stats(const TABLE *const table_arg, THD *const thd,
                                HA_CHECK_OPT *const check_opt) {
  DBUG_ENTER_FUNC();

  // find per column family key ranges which need to be queried
  std::unordered_map<rocksdb::ColumnFamilyHandle *, std::vector<rocksdb::Range>>
      ranges;
  std::unordered_set<GL_INDEX_ID> ids_to_check;
  std::vector<uchar> buf(table_arg->s->keys * 2 *
                         Rdb_key_def::INDEX_NUMBER_SIZE);
  for (uint i = 0; i < table_arg->s->keys; i++) {
    const auto bufp = &buf[i * 2 * Rdb_key_def::INDEX_NUMBER_SIZE];
    const Rdb_key_def &kd = *m_key_descr_arr[i];
    ranges[kd.get_cf()].push_back(get_range(i, bufp));
    ids_to_check.insert(kd.get_gl_index_id());
  }

  // for analyze statements, force flush on memtable to get accurate cardinality
  Rdb_cf_manager &cf_manager = rdb_get_cf_manager();
  if (thd != nullptr && THDVAR(thd, flush_memtable_on_analyze) &&
      !rocksdb_pause_background_work) {
    for (auto it : ids_to_check) {
      rdb->Flush(rocksdb::FlushOptions(), cf_manager.get_cf(it.cf_id));
    }
  }

  // get RocksDB table properties for these ranges
  rocksdb::TablePropertiesCollection props;
  for (auto it : ranges) {
    const auto old_size __attribute__((__unused__)) = props.size();
    const auto status = rdb->GetPropertiesOfTablesInRange(
        it.first, &it.second[0], it.second.size(), &props);
    DBUG_ASSERT(props.size() >= old_size);
    if (!status.ok())
      DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
  }

  int num_sst = 0;
  // group stats per index id
  std::unordered_map<GL_INDEX_ID, Rdb_index_stats> stats;
  for (const auto &it : ids_to_check) {
    // Initialize the stats to 0. If there are no files that contain
    // this gl_index_id, then 0 should be stored for the cached stats.
    stats[it] = Rdb_index_stats(it);
  }
  for (const auto &it : props) {
    std::vector<Rdb_index_stats> sst_stats;
    Rdb_tbl_prop_coll::read_stats_from_tbl_props(it.second, &sst_stats);
    /*
      sst_stats is a list of index statistics for indexes that have entries
      in the current SST file.
    */
    for (const auto &it1 : sst_stats) {
      /*
        Only update statistics for indexes that belong to this SQL table.

        The reason is: We are walking through all SST files that have
        entries from this table (and so can compute good statistics). For
        other SQL tables, it can be that we're only seeing a small fraction
        of table's entries (and so we can't update statistics based on that).
      */
      if (ids_to_check.find(it1.m_gl_index_id) == ids_to_check.end())
        continue;

      auto kd = ddl_manager.safe_find(it1.m_gl_index_id);
      DBUG_ASSERT(kd != nullptr);
      stats[it1.m_gl_index_id].merge(it1, true, kd->max_storage_fmt_length());
    }
    num_sst++;
  }

  // set and persist new stats
  ddl_manager.set_stats(stats);
  ddl_manager.persist_stats(true);

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

int ha_rocksdb::analyze(THD *const thd, HA_CHECK_OPT *const check_opt) {
  DBUG_ENTER_FUNC();

  if (!table) {
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  DBUG_RETURN(calculate_stats(table, thd, check_opt));
}

void ha_rocksdb::get_auto_increment(ulonglong off, ulonglong inc,
                                    ulonglong nb_desired_values,
                                    ulonglong *const first_value,
                                    ulonglong *const nb_reserved_values) {
  /*
    MySQL has a somewhat complicated way of handling the auto-increment value.
    The first time get_auto_increment is called for a statement,
    nb_desired_values is the estimate for how many values will be needed.  The
    engine can then reserve some values, and those will be automatically used
    by MySQL, until a hard-coded value shows up in the insert statement, after
    which MySQL again calls this function to reset its starting value.
   *
    For simplicity we will just ignore nb_desired_values - we aren't going to
    reserve any extra values for a multi-insert statement.  Each row will
    simply acquire the next value as needed and we will always tell MySQL that
    we only reserved 1 value.  Since we are using an atomic value for
    m_auto_incr_val this should be safe - if we had to grab a mutex, doing
    an actual reserve of some values might be a better solution.
   */
  DEBUG_SYNC(ha_thd(), "rocksdb.autoinc_vars");

  if (off > inc) {
    off = 1;
  }

  // Local variable reference to simplify code below
  std::atomic<longlong> &auto_incr = m_tbl_def->m_auto_incr_val;

  if (inc == 1 && off == 1) {
    // Optimization for the standard case where we are always simply
    // incrementing from the last position
    *first_value = auto_incr++;
  } else {
    // The next value can be more complicated if either `inc` or 'off' is not 1
    longlong new_val;
    longlong last_val = auto_incr;

    // Loop until we can correctly update the atomic value
    do {
      // Calculate the next value in the auto increment series:
      //   offset + N * increment
      // where N is 0, 1, 2, ...
      //
      // For further information please visit:
      // http://dev.mysql.com/doc/refman/5.7/en/replication-options-master.html
      new_val = ((last_val + (inc - off) - 1) / inc) * inc + off;

      // Attempt to store the new value (plus 1 since m_auto_incr_val contains
      // the next available value) into the atomic value.  If the current
      // value no longer matches what we have in 'last_val' this will fail and
      // we will repeat the loop (`last_val` will automatically get updated
      // with the current value).
    } while (!auto_incr.compare_exchange_weak(last_val, new_val + 1));

    *first_value = new_val;
  }

  *nb_reserved_values = 1;
}

#ifndef DBUG_OFF

/* Debugger help function */
static char dbug_item_print_buf[512];

const char *dbug_print_item(Item *const item) {
  char *const buf = dbug_item_print_buf;
  String str(buf, sizeof(dbug_item_print_buf), &my_charset_bin);
  str.length(0);
  if (!item)
    return "(Item*)nullptr";
  item->print(&str, QT_ORDINARY);
  if (str.c_ptr() == buf)
    return buf;
  else
    return "Couldn't fit into buffer";
}

#endif /*DBUG_OFF*/

/**
  SQL layer calls this function to push an index condition.

  @details
    The condition is for index keyno (only one condition can be pushed at a
    time).
    The caller guarantees that condition refers only to index fields; besides
    that, fields must have

      $field->part_of_key.set_bit(keyno)

    which means that

       (handler->index_flags(keyno, $keypart, 0) & HA_KEYREAD_ONLY) == 1

    which means that field value can be restored from the index tuple.

  @return
    Part of condition we couldn't check (always nullptr).
*/

class Item *ha_rocksdb::idx_cond_push(uint keyno, class Item *const idx_cond) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(keyno != MAX_KEY);
  DBUG_ASSERT(idx_cond != nullptr);

  pushed_idx_cond = idx_cond;
  pushed_idx_cond_keyno = keyno;
  in_range_check_pushed_down = TRUE;

  /* We will check the whole condition */
  DBUG_RETURN(nullptr);
}

/*
  @brief
  Check the index condition.

  @detail
  Check the index condition. (The caller has unpacked all needed index
  columns into table->record[0])

  @return
    ICP_NO_MATCH - Condition not satisfied (caller should continue
                   scanning)
    OUT_OF_RANGE - We've left the range we're scanning (caller should
                   stop scanning and return HA_ERR_END_OF_FILE)

    ICP_MATCH    - Condition is satisfied (caller should fetch the record
                   and return it)
*/

enum icp_result ha_rocksdb::check_index_cond() const {
  DBUG_ASSERT(pushed_idx_cond);
  DBUG_ASSERT(pushed_idx_cond_keyno != MAX_KEY);

  if (end_range && compare_key_icp(end_range) > 0) {
    /* caller should return HA_ERR_END_OF_FILE already */
    return ICP_OUT_OF_RANGE;
  }

  return pushed_idx_cond->val_int() ? ICP_MATCH : ICP_NO_MATCH;
}

/**
  Checking if an index is used for ascending scan or not

  @detail
  Currently RocksDB does not support bloom filter for
  prefix lookup + descending scan, but supports bloom filter for
  prefix lookup + ascending scan. This function returns true if
  the scan pattern is absolutely ascending.
  @param kd
  @param find_flag
*/
bool ha_rocksdb::is_ascending(const Rdb_key_def &kd,
                              enum ha_rkey_function find_flag) const {
  bool is_ascending;
  switch (find_flag) {
  case HA_READ_KEY_EXACT: {
    is_ascending = !kd.m_is_reverse_cf;
    break;
  }
  case HA_READ_PREFIX: {
    is_ascending = true;
    break;
  }
  case HA_READ_KEY_OR_NEXT:
  case HA_READ_AFTER_KEY: {
    is_ascending = !kd.m_is_reverse_cf;
    break;
  }
  case HA_READ_KEY_OR_PREV:
  case HA_READ_BEFORE_KEY:
  case HA_READ_PREFIX_LAST:
  case HA_READ_PREFIX_LAST_OR_PREV: {
    is_ascending = kd.m_is_reverse_cf;
    break;
  }
  default:
    is_ascending = false;
  }
  return is_ascending;
}

/*
  Checks if inplace alter is supported for a given operation.
*/

my_core::enum_alter_inplace_result ha_rocksdb::check_if_supported_inplace_alter(
    TABLE *altered_table, my_core::Alter_inplace_info *const ha_alter_info) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(ha_alter_info != nullptr);

  if (ha_alter_info->handler_flags &
      ~(my_core::Alter_inplace_info::DROP_INDEX |
        my_core::Alter_inplace_info::DROP_UNIQUE_INDEX |
        my_core::Alter_inplace_info::ADD_INDEX |
        my_core::Alter_inplace_info::ADD_UNIQUE_INDEX)) {
    DBUG_RETURN(my_core::HA_ALTER_INPLACE_NOT_SUPPORTED);
  }

  /* We don't support unique keys on table w/ no primary keys */
  if ((ha_alter_info->handler_flags &
       my_core::Alter_inplace_info::ADD_UNIQUE_INDEX) &&
      has_hidden_pk(altered_table)) {
    DBUG_RETURN(my_core::HA_ALTER_INPLACE_NOT_SUPPORTED);
  }

  DBUG_RETURN(my_core::HA_ALTER_INPLACE_SHARED_LOCK_AFTER_PREPARE);
}

/**
  Allows the storage engine to update internal structures with concurrent
  writes blocked. If check_if_supported_inplace_alter() returns
  HA_ALTER_INPLACE_NO_LOCK_AFTER_PREPARE or
  HA_ALTER_INPLACE_SHARED_AFTER_PREPARE, this function is called with
  exclusive lock otherwise the same level of locking as for
  inplace_alter_table() will be used.

  @note Storage engines are responsible for reporting any errors by
  calling my_error()/print_error()

  @note If this function reports error, commit_inplace_alter_table()
  will be called with commit= false.

  @note For partitioning, failing to prepare one partition, means that
  commit_inplace_alter_table() will be called to roll back changes for
  all partitions. This means that commit_inplace_alter_table() might be
  called without prepare_inplace_alter_table() having been called first
  for a given partition.

  @param    altered_table     TABLE object for new version of table.
  @param    ha_alter_info     Structure describing changes to be done
                              by ALTER TABLE and holding data used
                              during in-place alter.

  @retval   true              Error
  @retval   false             Success
*/
bool ha_rocksdb::prepare_inplace_alter_table(
    TABLE *const altered_table,
    my_core::Alter_inplace_info *const ha_alter_info) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(altered_table != nullptr);
  DBUG_ASSERT(ha_alter_info != nullptr);

  const uint n_dropped_keys = ha_alter_info->index_drop_count;
  const uint n_added_keys = ha_alter_info->index_add_count;
  const uint old_n_keys = m_tbl_def->m_key_count;
  uint new_n_keys = altered_table->s->keys;

  if (has_hidden_pk(altered_table)) {
    new_n_keys += 1;
  }

  std::shared_ptr<Rdb_key_def> *const old_key_descr =
      m_tbl_def->m_key_descr_arr;
  std::shared_ptr<Rdb_key_def> *const new_key_descr =
      new std::shared_ptr<Rdb_key_def>[new_n_keys];

  Rdb_tbl_def *const new_tdef = new Rdb_tbl_def(m_tbl_def->full_tablename());
  new_tdef->m_key_descr_arr = new_key_descr;
  new_tdef->m_key_count = new_n_keys;
  new_tdef->m_auto_incr_val =
      m_tbl_def->m_auto_incr_val.load(std::memory_order_relaxed);
  new_tdef->m_hidden_pk_val =
      m_tbl_def->m_hidden_pk_val.load(std::memory_order_relaxed);

  if (ha_alter_info->handler_flags &
          (my_core::Alter_inplace_info::DROP_INDEX |
           my_core::Alter_inplace_info::DROP_UNIQUE_INDEX |
           my_core::Alter_inplace_info::ADD_INDEX |
           my_core::Alter_inplace_info::ADD_UNIQUE_INDEX) &&
      create_key_defs(altered_table, new_tdef, table, m_tbl_def)) {
    /* Delete the new key descriptors */
    delete[] new_key_descr;

    /*
      Explicitly mark as nullptr so we don't accidentally remove entries
      from data dictionary on cleanup (or cause double delete[]).
    */
    new_tdef->m_key_descr_arr = nullptr;
    delete new_tdef;

    my_printf_error(ER_UNKNOWN_ERROR,
                    "MyRocks failed creating new key definitions during alter.",
                    MYF(0));
    DBUG_RETURN(HA_EXIT_FAILURE);
  }

  std::unordered_set<std::shared_ptr<Rdb_key_def>> added_indexes;
  std::unordered_set<GL_INDEX_ID> dropped_index_ids;

  uint i;
  uint j;
  const KEY *key;

  /* Determine which(if any) key definition(s) need to be dropped */
  for (i = 0; i < ha_alter_info->index_drop_count; i++) {
    const KEY *const key = ha_alter_info->index_drop_buffer[i];
    for (j = 0; j < old_n_keys; j++) {
      if (!old_key_descr[j]->m_name.compare(key->name)) {
        dropped_index_ids.insert(old_key_descr[j]->get_gl_index_id());
        break;
      }
    }
  }

  DBUG_ASSERT(dropped_index_ids.size() == ha_alter_info->index_drop_count);

  /* Determine which(if any) key definitions(s) need to be added */
  for (i = 0; i < ha_alter_info->index_add_count; i++) {
    key = &ha_alter_info->key_info_buffer[ha_alter_info->index_add_buffer[i]];
    for (j = 0; j < new_n_keys; j++) {
      if (!new_key_descr[j]->m_name.compare(key->name)) {
        added_indexes.insert(new_key_descr[j]);
        break;
      }
    }
  }

  DBUG_ASSERT(added_indexes.size() == ha_alter_info->index_add_count);

  ha_alter_info->handler_ctx = new Rdb_inplace_alter_ctx(
      new_tdef, old_key_descr, new_key_descr, old_n_keys, new_n_keys,
      added_indexes, dropped_index_ids, n_added_keys, n_dropped_keys);

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/**
  Alter the table structure in-place with operations specified using
  HA_ALTER_FLAGS and Alter_inplace_info. The level of concurrency allowed
  during this operation depends on the return value from
  check_if_supported_inplace_alter().

  @note Storage engines are responsible for reporting any errors by
  calling my_error()/print_error()

  @note If this function reports error, commit_inplace_alter_table()
  will be called with commit= false.

  @param    altered_table     TABLE object for new version of table.
  @param    ha_alter_info     Structure describing changes to be done
                              by ALTER TABLE and holding data used
                              during in-place alter.

  @retval   true              Error
  @retval   false             Success
*/
bool ha_rocksdb::inplace_alter_table(
    TABLE *const altered_table,
    my_core::Alter_inplace_info *const ha_alter_info) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(altered_table != nullptr);
  DBUG_ASSERT(ha_alter_info != nullptr);
  DBUG_ASSERT(ha_alter_info->handler_ctx != nullptr);

  Rdb_inplace_alter_ctx *const ctx =
      static_cast<Rdb_inplace_alter_ctx *>(ha_alter_info->handler_ctx);

  if (ha_alter_info->handler_flags &
      (my_core::Alter_inplace_info::ADD_INDEX |
       my_core::Alter_inplace_info::ADD_UNIQUE_INDEX)) {
    /*
      Buffers need to be set up again to account for new, possibly longer
      secondary keys.
    */
    free_key_buffers();

    DBUG_ASSERT(ctx != nullptr);

    /*
      If adding unique index, allocate special buffers for duplicate checking.
    */
    int err;
    if ((err = alloc_key_buffers(
             altered_table, ctx->m_new_tdef,
             ha_alter_info->handler_flags &
                 my_core::Alter_inplace_info::ADD_UNIQUE_INDEX))) {
      my_printf_error(ER_UNKNOWN_ERROR,
                      "MyRocks failed allocating key buffers during alter.",
                      MYF(0));
      DBUG_RETURN(err);
    }

    /* Populate all new secondary keys by scanning the primary key. */
    if ((err = inplace_populate_sk(altered_table, ctx->m_added_indexes))) {
      my_printf_error(ER_UNKNOWN_ERROR,
                      "MyRocks failed populating secondary key during alter.",
                      MYF(0));
      DBUG_RETURN(HA_EXIT_FAILURE);
    }
  }

  DBUG_EXECUTE_IF("myrocks_simulate_index_create_rollback", {
    dbug_create_err_inplace_alter();
    DBUG_RETURN(HA_EXIT_FAILURE);
  };);

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

/**
 Scan the Primary Key index entries and populate the new secondary keys.
*/
int ha_rocksdb::inplace_populate_sk(
    TABLE *const new_table_arg,
    const std::unordered_set<std::shared_ptr<Rdb_key_def>> &indexes) {
  DBUG_ENTER_FUNC();

  const std::unique_ptr<rocksdb::WriteBatch> wb = dict_manager.begin();
  rocksdb::WriteBatch *const batch = wb.get();

  /* Update the data dictionary */
  std::unordered_set<GL_INDEX_ID> create_index_ids;
  for (const auto &index : indexes) {
    create_index_ids.insert(index->get_gl_index_id());
  }
  dict_manager.add_create_index(create_index_ids, batch);
  dict_manager.commit(batch);

  const bool hidden_pk_exists = has_hidden_pk(table);

  int res = 0;
  Rdb_transaction *tx = get_or_create_tx(table->in_use);

  /*
    There is one specific scenario where m_sst_info may not be nullptr. This
    happens if the handler we're using happens to be the handler where the PK
    bulk load was done on. The sequence of events that lead to this is as
    follows (T1 is PK bulk load, T2 is SK alter table):

    T1: Execute last INSERT statement
    T1: Return TABLE and handler object back to Table_cache_manager
    T1: Close connection
    T2: Execute ALTER statement
    T2: Take same TABLE/handler from Table_cache_manager
    T2: Call closefrm which will call finalize_bulk_load on every other open
        table/handler *except* the one it's on.
    T2: Acquire stale snapshot of PK
    T1: Call finalize_bulk_load

    This is rare because usually, closefrm will call the destructor (and thus
    finalize_bulk_load) on the handler where PK bulk load is done. However, if
    the thread ids of the bulk load thread and the alter thread differ by a
    multiple of table_cache_instances (8 by default), then they hash to the
    same bucket in Table_cache_manager and the alter thread will not not call
    the destructor on the handler it is holding. Thus, its m_sst_info will not
    be nullptr.

    At this point, it is safe to refresh the snapshot because we know all other
    open handlers have been closed at this point, and the one we're on is the
    only one left.
  */
  if (m_sst_info != nullptr) {
    if ((res = finalize_bulk_load())) {
      DBUG_RETURN(res);
    }
    tx->commit();
  }

  const ulonglong rdb_merge_buf_size = THDVAR(ha_thd(), merge_buf_size);
  const ulonglong rdb_merge_combine_read_size =
      THDVAR(ha_thd(), merge_combine_read_size);

  for (const auto &index : indexes) {
    const rocksdb::Comparator *index_comp = index->get_cf()->GetComparator();
    bool is_unique_index =
        new_table_arg->key_info[index->get_keyno()].flags & HA_NOSAME;

    Rdb_index_merge rdb_merge(thd_rocksdb_tmpdir(), rdb_merge_buf_size,
                              rdb_merge_combine_read_size, index_comp);

    if ((res = rdb_merge.init())) {
      DBUG_RETURN(res);
    }

    /*
      Note: We pass in the currently existing table + tbl_def object here,
      as the pk index position may have changed in the case of hidden primary
      keys.
    */
    const uint pk = pk_index(table, m_tbl_def);
    ha_index_init(pk, true);

    /* Scan each record in the primary key in order */
    for (res = index_first(table->record[0]); res == 0;
         res = index_next(table->record[0])) {
      longlong hidden_pk_id = 0;
      if (hidden_pk_exists && read_hidden_pk_id_from_rowkey(&hidden_pk_id)) {
        // NO_LINT_DEBUG
        sql_print_error("Error retrieving hidden pk id.");
        ha_index_end();
        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
      }

      /* Create new secondary index entry */
      const int new_packed_size = index->pack_record(
          new_table_arg, m_pack_buffer, table->record[0], m_sk_packed_tuple,
          &m_sk_tails, should_store_row_debug_checksums(), hidden_pk_id);

      const rocksdb::Slice key = rocksdb::Slice(
          reinterpret_cast<const char *>(m_sk_packed_tuple), new_packed_size);
      const rocksdb::Slice val =
          rocksdb::Slice(reinterpret_cast<const char *>(m_sk_tails.ptr()),
                         m_sk_tails.get_current_pos());

      /*
        Add record to offset tree in preparation for writing out to
        disk in sorted chunks.
      */
      if ((res = rdb_merge.add(key, val))) {
        ha_index_end();
        DBUG_RETURN(res);
      }
    }

    if (res != HA_ERR_END_OF_FILE) {
      // NO_LINT_DEBUG
      sql_print_error("Error retrieving index entry from primary key.");
      ha_index_end();
      DBUG_RETURN(res);
    }

    ha_index_end();

    /*
      Perform an n-way merge of n sorted buffers on disk, then writes all
      results to RocksDB via SSTFileWriter API.
    */
    rocksdb::Slice merge_key;
    rocksdb::Slice merge_val;

    struct unique_sk_buf_info sk_info;
    sk_info.dup_sk_buf = m_dup_sk_packed_tuple;
    sk_info.dup_sk_buf_old = m_dup_sk_packed_tuple_old;

    while ((res = rdb_merge.next(&merge_key, &merge_val)) == 0) {
      /* Perform uniqueness check if needed */
      if (is_unique_index) {
        if (check_duplicate_sk(new_table_arg, *index, &merge_key, &sk_info)) {
          /*
            Duplicate entry found when trying to create unique secondary key.
            We need to unpack the record into new_table_arg->record[0] as it
            is used inside print_keydup_error so that the error message shows
            the duplicate record.
          */
          if (index->unpack_record(new_table_arg, new_table_arg->record[0],
                                   &merge_key, nullptr,
                                   m_verify_row_debug_checksums)) {
            /* Should never reach here */
            DBUG_ASSERT(0);
          }

          print_keydup_error(new_table_arg,
                             &new_table_arg->key_info[index->get_keyno()],
                             MYF(0));
          DBUG_RETURN(ER_DUP_ENTRY);
        }
      }

      /*
        Insert key and slice to SST via SSTFileWriter API.
      */
      if ((res = bulk_load_key(tx, *index, merge_key, merge_val))) {
        break;
      }
    }

    /*
      Here, res == -1 means that we are finished, while > 0 means an error
      occurred.
    */
    if (res > 0) {
      // NO_LINT_DEBUG
      sql_print_error("Error while bulk loading keys in external merge sort.");
      DBUG_RETURN(res);
    }

    if ((res = tx->finish_bulk_load())) {
      // NO_LINT_DEBUG
      sql_print_error("Error finishing bulk load.");
      DBUG_RETURN(res);
    }
  }

  /*
    Explicitly tell jemalloc to clean up any unused dirty pages at this point.
    See https://reviews.facebook.net/D63723 for more details.
  */
  purge_all_jemalloc_arenas();

  DBUG_EXECUTE_IF("crash_during_online_index_creation", DBUG_SUICIDE(););
  DBUG_RETURN(res);
}

/**
  Commit or rollback the changes made during prepare_inplace_alter_table()
  and inplace_alter_table() inside the storage engine.
  Note that in case of rollback the allowed level of concurrency during
  this operation will be the same as for inplace_alter_table() and thus
  might be higher than during prepare_inplace_alter_table(). (For example,
  concurrent writes were blocked during prepare, but might not be during
  rollback).

  @note Storage engines are responsible for reporting any errors by
  calling my_error()/print_error()

  @note If this function with commit= true reports error, it will be called
  again with commit= false.

  @note In case of partitioning, this function might be called for rollback
  without prepare_inplace_alter_table() having been called first.
  Also partitioned tables sets ha_alter_info->group_commit_ctx to a NULL
  terminated array of the partitions handlers and if all of them are
  committed as one, then group_commit_ctx should be set to NULL to indicate
  to the partitioning handler that all partitions handlers are committed.
  @see prepare_inplace_alter_table().

  @param    altered_table     TABLE object for new version of table.
  @param    ha_alter_info     Structure describing changes to be done
                              by ALTER TABLE and holding data used
                              during in-place alter.
  @param    commit            True => Commit, False => Rollback.

  @retval   true              Error
  @retval   false             Success
*/
bool ha_rocksdb::commit_inplace_alter_table(
    my_core::TABLE *const altered_table,
    my_core::Alter_inplace_info *const ha_alter_info, bool commit) {
  DBUG_ENTER_FUNC();

  DBUG_ASSERT(altered_table != nullptr);
  DBUG_ASSERT(ha_alter_info != nullptr);

  Rdb_inplace_alter_ctx *const ctx0 =
      static_cast<Rdb_inplace_alter_ctx *>(ha_alter_info->handler_ctx);

  /*
    IMPORTANT: When rollback is requested, mysql will abort with
    an assertion failure. That means every failed commit during inplace alter
    table will result in a fatal error on the server. Indexes ongoing creation
    will be detected when the server restarts, and dropped.

    For partitioned tables, a rollback call to this function (commit == false)
    is done for each partition.  A successful commit call only executes once
    for all partitions.
  */
  if (!commit) {
    /* If ctx has not been created yet, nothing to do here */
    if (!ctx0) {
      DBUG_RETURN(HA_EXIT_SUCCESS);
    }

    /*
      Cannot call destructor for Rdb_tbl_def directly because we don't want to
      erase the mappings inside the ddl_manager, as the old_key_descr is still
      using them.
    */
    if (ctx0->m_new_key_descr) {
      /* Delete the new key descriptors */
      for (uint i = 0; i < ctx0->m_new_tdef->m_key_count; i++) {
        ctx0->m_new_key_descr[i] = nullptr;
      }

      delete[] ctx0->m_new_key_descr;
      ctx0->m_new_key_descr = nullptr;
      ctx0->m_new_tdef->m_key_descr_arr = nullptr;

      delete ctx0->m_new_tdef;
    }

    /* Rollback any partially created indexes */
    dict_manager.rollback_ongoing_index_creation();

    DBUG_RETURN(HA_EXIT_SUCCESS);
  }

  DBUG_ASSERT(ctx0);

  /*
    For partitioned tables, we need to commit all changes to all tables at
    once, unlike in the other inplace alter API methods.
  */
  inplace_alter_handler_ctx **ctx_array;
  inplace_alter_handler_ctx *ctx_single[2];

  if (ha_alter_info->group_commit_ctx) {
    DBUG_EXECUTE_IF("crash_during_index_creation_partition", DBUG_SUICIDE(););
    ctx_array = ha_alter_info->group_commit_ctx;
  } else {
    ctx_single[0] = ctx0;
    ctx_single[1] = nullptr;
    ctx_array = ctx_single;
  }

  DBUG_ASSERT(ctx0 == ctx_array[0]);
  ha_alter_info->group_commit_ctx = nullptr;

  if (ha_alter_info->handler_flags &
      (my_core::Alter_inplace_info::DROP_INDEX |
       my_core::Alter_inplace_info::DROP_UNIQUE_INDEX |
       my_core::Alter_inplace_info::ADD_INDEX |
       my_core::Alter_inplace_info::ADD_UNIQUE_INDEX)) {
    const std::unique_ptr<rocksdb::WriteBatch> wb = dict_manager.begin();
    rocksdb::WriteBatch *const batch = wb.get();
    std::unordered_set<GL_INDEX_ID> create_index_ids;

    m_tbl_def = ctx0->m_new_tdef;
    m_key_descr_arr = m_tbl_def->m_key_descr_arr;
    m_pk_descr = m_key_descr_arr[pk_index(altered_table, m_tbl_def)];

    dict_manager.lock();
    for (inplace_alter_handler_ctx **pctx = ctx_array; *pctx; pctx++) {
      Rdb_inplace_alter_ctx *const ctx =
          static_cast<Rdb_inplace_alter_ctx *>(*pctx);

      /* Mark indexes to be dropped */
      dict_manager.add_drop_index(ctx->m_dropped_index_ids, batch);

      for (const auto &index : ctx->m_added_indexes) {
        create_index_ids.insert(index->get_gl_index_id());
      }

      if (ddl_manager.put_and_write(ctx->m_new_tdef, batch)) {
        /*
          Failed to write new entry into data dictionary, this should never
          happen.
        */
        DBUG_ASSERT(0);
      }
    }

    if (dict_manager.commit(batch)) {
      /*
        Should never reach here. We assume MyRocks will abort if commit fails.
      */
      DBUG_ASSERT(0);
    }

    dict_manager.unlock();

    /* Mark ongoing create indexes as finished/remove from data dictionary */
    dict_manager.finish_indexes_operation(
        create_index_ids, Rdb_key_def::DDL_CREATE_INDEX_ONGOING);

    /*
      We need to recalculate the index stats here manually.  The reason is that
      the secondary index does not exist inside
      m_index_num_to_keydef until it is committed to the data dictionary, which
      prevents us from updating the stats normally as the ddl_manager cannot
      find the proper gl_index_ids yet during adjust_stats calls.
    */
    if (calculate_stats(altered_table, nullptr, nullptr)) {
      /* Failed to update index statistics, should never happen */
      DBUG_ASSERT(0);
    }

    rdb_drop_idx_thread.signal();
  }

  DBUG_RETURN(HA_EXIT_SUCCESS);
}

#define SHOW_FNAME(name) rocksdb_show_##name

#define DEF_SHOW_FUNC(name, key)                                               \
  static int SHOW_FNAME(name)(MYSQL_THD thd, SHOW_VAR * var, char *buff) {     \
    rocksdb_status_counters.name =                                             \
        rocksdb_stats->getTickerCount(rocksdb::key);                           \
    var->type = SHOW_LONGLONG;                                                 \
    var->value = (char *)&rocksdb_status_counters.name;                        \
    return HA_EXIT_SUCCESS;                                                    \
  }

#define DEF_STATUS_VAR(name)                                                   \
  { "rocksdb_" #name, (char *)&SHOW_FNAME(name), SHOW_FUNC }

#define DEF_STATUS_VAR_PTR(name, ptr, option)                                  \
  { "rocksdb_" name, (char *)ptr, option }

#define DEF_STATUS_VAR_FUNC(name, ptr, option)                                 \
  { name, reinterpret_cast<char *>(ptr), option }

struct rocksdb_status_counters_t {
  uint64_t block_cache_miss;
  uint64_t block_cache_hit;
  uint64_t block_cache_add;
  uint64_t block_cache_index_miss;
  uint64_t block_cache_index_hit;
  uint64_t block_cache_filter_miss;
  uint64_t block_cache_filter_hit;
  uint64_t block_cache_data_miss;
  uint64_t block_cache_data_hit;
  uint64_t bloom_filter_useful;
  uint64_t memtable_hit;
  uint64_t memtable_miss;
  uint64_t compaction_key_drop_new;
  uint64_t compaction_key_drop_obsolete;
  uint64_t compaction_key_drop_user;
  uint64_t number_keys_written;
  uint64_t number_keys_read;
  uint64_t number_keys_updated;
  uint64_t bytes_written;
  uint64_t bytes_read;
  uint64_t no_file_closes;
  uint64_t no_file_opens;
  uint64_t no_file_errors;
  uint64_t l0_slowdown_micros;
  uint64_t memtable_compaction_micros;
  uint64_t l0_num_files_stall_micros;
  uint64_t rate_limit_delay_millis;
  uint64_t num_iterators;
  uint64_t number_multiget_get;
  uint64_t number_multiget_keys_read;
  uint64_t number_multiget_bytes_read;
  uint64_t number_deletes_filtered;
  uint64_t number_merge_failures;
  uint64_t bloom_filter_prefix_checked;
  uint64_t bloom_filter_prefix_useful;
  uint64_t number_reseeks_iteration;
  uint64_t getupdatessince_calls;
  uint64_t block_cachecompressed_miss;
  uint64_t block_cachecompressed_hit;
  uint64_t wal_synced;
  uint64_t wal_bytes;
  uint64_t write_self;
  uint64_t write_other;
  uint64_t write_timedout;
  uint64_t write_wal;
  uint64_t flush_write_bytes;
  uint64_t compact_read_bytes;
  uint64_t compact_write_bytes;
  uint64_t number_superversion_acquires;
  uint64_t number_superversion_releases;
  uint64_t number_superversion_cleanups;
  uint64_t number_block_not_compressed;
};

static rocksdb_status_counters_t rocksdb_status_counters;

DEF_SHOW_FUNC(block_cache_miss, BLOCK_CACHE_MISS)
DEF_SHOW_FUNC(block_cache_hit, BLOCK_CACHE_HIT)
DEF_SHOW_FUNC(block_cache_add, BLOCK_CACHE_ADD)
DEF_SHOW_FUNC(block_cache_index_miss, BLOCK_CACHE_INDEX_MISS)
DEF_SHOW_FUNC(block_cache_index_hit, BLOCK_CACHE_INDEX_HIT)
DEF_SHOW_FUNC(block_cache_filter_miss, BLOCK_CACHE_FILTER_MISS)
DEF_SHOW_FUNC(block_cache_filter_hit, BLOCK_CACHE_FILTER_HIT)
DEF_SHOW_FUNC(block_cache_data_miss, BLOCK_CACHE_DATA_MISS)
DEF_SHOW_FUNC(block_cache_data_hit, BLOCK_CACHE_DATA_HIT)
DEF_SHOW_FUNC(bloom_filter_useful, BLOOM_FILTER_USEFUL)
DEF_SHOW_FUNC(memtable_hit, MEMTABLE_HIT)
DEF_SHOW_FUNC(memtable_miss, MEMTABLE_MISS)
DEF_SHOW_FUNC(compaction_key_drop_new, COMPACTION_KEY_DROP_NEWER_ENTRY)
DEF_SHOW_FUNC(compaction_key_drop_obsolete, COMPACTION_KEY_DROP_OBSOLETE)
DEF_SHOW_FUNC(compaction_key_drop_user, COMPACTION_KEY_DROP_USER)
DEF_SHOW_FUNC(number_keys_written, NUMBER_KEYS_WRITTEN)
DEF_SHOW_FUNC(number_keys_read, NUMBER_KEYS_READ)
DEF_SHOW_FUNC(number_keys_updated, NUMBER_KEYS_UPDATED)
DEF_SHOW_FUNC(bytes_written, BYTES_WRITTEN)
DEF_SHOW_FUNC(bytes_read, BYTES_READ)
DEF_SHOW_FUNC(no_file_closes, NO_FILE_CLOSES)
DEF_SHOW_FUNC(no_file_opens, NO_FILE_OPENS)
DEF_SHOW_FUNC(no_file_errors, NO_FILE_ERRORS)
DEF_SHOW_FUNC(l0_slowdown_micros, STALL_L0_SLOWDOWN_MICROS)
DEF_SHOW_FUNC(memtable_compaction_micros, STALL_MEMTABLE_COMPACTION_MICROS)
DEF_SHOW_FUNC(l0_num_files_stall_micros, STALL_L0_NUM_FILES_MICROS)
DEF_SHOW_FUNC(rate_limit_delay_millis, RATE_LIMIT_DELAY_MILLIS)
DEF_SHOW_FUNC(num_iterators, NO_ITERATORS)
DEF_SHOW_FUNC(number_multiget_get, NUMBER_MULTIGET_CALLS)
DEF_SHOW_FUNC(number_multiget_keys_read, NUMBER_MULTIGET_KEYS_READ)
DEF_SHOW_FUNC(number_multiget_bytes_read, NUMBER_MULTIGET_BYTES_READ)
DEF_SHOW_FUNC(number_deletes_filtered, NUMBER_FILTERED_DELETES)
DEF_SHOW_FUNC(number_merge_failures, NUMBER_MERGE_FAILURES)
DEF_SHOW_FUNC(bloom_filter_prefix_checked, BLOOM_FILTER_PREFIX_CHECKED)
DEF_SHOW_FUNC(bloom_filter_prefix_useful, BLOOM_FILTER_PREFIX_USEFUL)
DEF_SHOW_FUNC(number_reseeks_iteration, NUMBER_OF_RESEEKS_IN_ITERATION)
DEF_SHOW_FUNC(getupdatessince_calls, GET_UPDATES_SINCE_CALLS)
DEF_SHOW_FUNC(block_cachecompressed_miss, BLOCK_CACHE_COMPRESSED_MISS)
DEF_SHOW_FUNC(block_cachecompressed_hit, BLOCK_CACHE_COMPRESSED_HIT)
DEF_SHOW_FUNC(wal_synced, WAL_FILE_SYNCED)
DEF_SHOW_FUNC(wal_bytes, WAL_FILE_BYTES)
DEF_SHOW_FUNC(write_self, WRITE_DONE_BY_SELF)
DEF_SHOW_FUNC(write_other, WRITE_DONE_BY_OTHER)
DEF_SHOW_FUNC(write_timedout, WRITE_TIMEDOUT)
DEF_SHOW_FUNC(write_wal, WRITE_WITH_WAL)
DEF_SHOW_FUNC(flush_write_bytes, FLUSH_WRITE_BYTES)
DEF_SHOW_FUNC(compact_read_bytes, COMPACT_READ_BYTES)
DEF_SHOW_FUNC(compact_write_bytes, COMPACT_WRITE_BYTES)
DEF_SHOW_FUNC(number_superversion_acquires, NUMBER_SUPERVERSION_ACQUIRES)
DEF_SHOW_FUNC(number_superversion_releases, NUMBER_SUPERVERSION_RELEASES)
DEF_SHOW_FUNC(number_superversion_cleanups, NUMBER_SUPERVERSION_CLEANUPS)
DEF_SHOW_FUNC(number_block_not_compressed, NUMBER_BLOCK_NOT_COMPRESSED)

static void myrocks_update_status() {
  export_stats.rows_deleted = global_stats.rows[ROWS_DELETED];
  export_stats.rows_inserted = global_stats.rows[ROWS_INSERTED];
  export_stats.rows_read = global_stats.rows[ROWS_READ];
  export_stats.rows_updated = global_stats.rows[ROWS_UPDATED];

  export_stats.system_rows_deleted = global_stats.system_rows[ROWS_DELETED];
  export_stats.system_rows_inserted = global_stats.system_rows[ROWS_INSERTED];
  export_stats.system_rows_read = global_stats.system_rows[ROWS_READ];
  export_stats.system_rows_updated = global_stats.system_rows[ROWS_UPDATED];
}

static SHOW_VAR myrocks_status_variables[] = {
    DEF_STATUS_VAR_FUNC("rows_deleted", &export_stats.rows_deleted,
                        SHOW_LONGLONG),
    DEF_STATUS_VAR_FUNC("rows_inserted", &export_stats.rows_inserted,
                        SHOW_LONGLONG),
    DEF_STATUS_VAR_FUNC("rows_read", &export_stats.rows_read, SHOW_LONGLONG),
    DEF_STATUS_VAR_FUNC("rows_updated", &export_stats.rows_updated,
                        SHOW_LONGLONG),
    DEF_STATUS_VAR_FUNC("system_rows_deleted",
                        &export_stats.system_rows_deleted, SHOW_LONGLONG),
    DEF_STATUS_VAR_FUNC("system_rows_inserted",
                        &export_stats.system_rows_inserted, SHOW_LONGLONG),
    DEF_STATUS_VAR_FUNC("system_rows_read", &export_stats.system_rows_read,
                        SHOW_LONGLONG),
    DEF_STATUS_VAR_FUNC("system_rows_updated",
                        &export_stats.system_rows_updated, SHOW_LONGLONG),

    {NullS, NullS, SHOW_LONG}};

static void show_myrocks_vars(THD *thd, SHOW_VAR *var, char *buff) {
  myrocks_update_status();
  var->type = SHOW_ARRAY;
  var->value = reinterpret_cast<char *>(&myrocks_status_variables);
}

static SHOW_VAR rocksdb_status_vars[] = {
    DEF_STATUS_VAR(block_cache_miss),
    DEF_STATUS_VAR(block_cache_hit),
    DEF_STATUS_VAR(block_cache_add),
    DEF_STATUS_VAR(block_cache_index_miss),
    DEF_STATUS_VAR(block_cache_index_hit),
    DEF_STATUS_VAR(block_cache_filter_miss),
    DEF_STATUS_VAR(block_cache_filter_hit),
    DEF_STATUS_VAR(block_cache_data_miss),
    DEF_STATUS_VAR(block_cache_data_hit),
    DEF_STATUS_VAR(bloom_filter_useful),
    DEF_STATUS_VAR(memtable_hit),
    DEF_STATUS_VAR(memtable_miss),
    DEF_STATUS_VAR(compaction_key_drop_new),
    DEF_STATUS_VAR(compaction_key_drop_obsolete),
    DEF_STATUS_VAR(compaction_key_drop_user),
    DEF_STATUS_VAR(number_keys_written),
    DEF_STATUS_VAR(number_keys_read),
    DEF_STATUS_VAR(number_keys_updated),
    DEF_STATUS_VAR(bytes_written),
    DEF_STATUS_VAR(bytes_read),
    DEF_STATUS_VAR(no_file_closes),
    DEF_STATUS_VAR(no_file_opens),
    DEF_STATUS_VAR(no_file_errors),
    DEF_STATUS_VAR(l0_slowdown_micros),
    DEF_STATUS_VAR(memtable_compaction_micros),
    DEF_STATUS_VAR(l0_num_files_stall_micros),
    DEF_STATUS_VAR(rate_limit_delay_millis),
    DEF_STATUS_VAR(num_iterators),
    DEF_STATUS_VAR(number_multiget_get),
    DEF_STATUS_VAR(number_multiget_keys_read),
    DEF_STATUS_VAR(number_multiget_bytes_read),
    DEF_STATUS_VAR(number_deletes_filtered),
    DEF_STATUS_VAR(number_merge_failures),
    DEF_STATUS_VAR(bloom_filter_prefix_checked),
    DEF_STATUS_VAR(bloom_filter_prefix_useful),
    DEF_STATUS_VAR(number_reseeks_iteration),
    DEF_STATUS_VAR(getupdatessince_calls),
    DEF_STATUS_VAR(block_cachecompressed_miss),
    DEF_STATUS_VAR(block_cachecompressed_hit),
    DEF_STATUS_VAR(wal_synced),
    DEF_STATUS_VAR(wal_bytes),
    DEF_STATUS_VAR(write_self),
    DEF_STATUS_VAR(write_other),
    DEF_STATUS_VAR(write_timedout),
    DEF_STATUS_VAR(write_wal),
    DEF_STATUS_VAR(flush_write_bytes),
    DEF_STATUS_VAR(compact_read_bytes),
    DEF_STATUS_VAR(compact_write_bytes),
    DEF_STATUS_VAR(number_superversion_acquires),
    DEF_STATUS_VAR(number_superversion_releases),
    DEF_STATUS_VAR(number_superversion_cleanups),
    DEF_STATUS_VAR(number_block_not_compressed),
    DEF_STATUS_VAR_PTR("snapshot_conflict_errors",
                       &rocksdb_snapshot_conflict_errors, SHOW_LONGLONG),
    DEF_STATUS_VAR_PTR("wal_group_syncs", &rocksdb_wal_group_syncs,
                       SHOW_LONGLONG),
    DEF_STATUS_VAR_PTR("number_stat_computes", &rocksdb_number_stat_computes,
                       SHOW_LONGLONG),
    DEF_STATUS_VAR_PTR("number_sst_entry_put", &rocksdb_num_sst_entry_put,
                       SHOW_LONGLONG),
    DEF_STATUS_VAR_PTR("number_sst_entry_delete", &rocksdb_num_sst_entry_delete,
                       SHOW_LONGLONG),
    DEF_STATUS_VAR_PTR("number_sst_entry_singledelete",
                       &rocksdb_num_sst_entry_singledelete, SHOW_LONGLONG),
    DEF_STATUS_VAR_PTR("number_sst_entry_merge", &rocksdb_num_sst_entry_merge,
                       SHOW_LONGLONG),
    DEF_STATUS_VAR_PTR("number_sst_entry_other", &rocksdb_num_sst_entry_other,
                       SHOW_LONGLONG),
    {"rocksdb", reinterpret_cast<char *>(&show_myrocks_vars), SHOW_FUNC},
    {NullS, NullS, SHOW_LONG}};

/*
  Background thread's main logic
*/

void Rdb_background_thread::run() {
  // How many seconds to wait till flushing the WAL next time.
  const int WAKE_UP_INTERVAL = 1;

  timespec ts_next_sync;
  clock_gettime(CLOCK_REALTIME, &ts_next_sync);
  ts_next_sync.tv_sec += WAKE_UP_INTERVAL;

  for (;;) {
    // Wait until the next timeout or until we receive a signal to stop the
    // thread. Request to stop the thread should only be triggered when the
    // storage engine is being unloaded.
    mysql_mutex_lock(&m_signal_mutex);
    const auto ret __attribute__((__unused__)) =
        mysql_cond_timedwait(&m_signal_cond, &m_signal_mutex, &ts_next_sync);

    // Check that we receive only the expected error codes.
    DBUG_ASSERT(ret == 0 || ret == ETIMEDOUT);
    const bool local_stop = m_stop;
    const bool local_save_stats = m_save_stats;
    reset();
    mysql_mutex_unlock(&m_signal_mutex);

    if (local_stop) {
      // If we're here then that's because condition variable was signaled by
      // another thread and we're shutting down. Break out the loop to make
      // sure that shutdown thread can proceed.
      break;
    }

    // This path should be taken only when the timer expired.
    DBUG_ASSERT(ret == ETIMEDOUT);

    if (local_save_stats) {
      ddl_manager.persist_stats();
    }

    timespec ts;
    clock_gettime(CLOCK_REALTIME, &ts);

    // Flush the WAL.
    if (rdb && rocksdb_background_sync) {
      DBUG_ASSERT(!rocksdb_db_options.allow_mmap_writes);
      const rocksdb::Status s = rdb->SyncWAL();
      if (!s.ok()) {
        rdb_handle_io_error(s, RDB_IO_ERROR_BG_THREAD);
      }
    }

    // Set the next timestamp for mysql_cond_timedwait() (which ends up calling
    // pthread_cond_timedwait()) to wait on.
    ts_next_sync.tv_sec = ts.tv_sec + WAKE_UP_INTERVAL;
  }

  // save remaining stats which might've left unsaved
  ddl_manager.persist_stats();
}

/**
  Deciding if it is possible to use bloom filter or not.

  @detail
   Even if bloom filter exists, it is not always possible
   to use bloom filter. If using bloom filter when you shouldn't,
   false negative may happen -- fewer rows than expected may be returned.
   It is users' responsibility to use bloom filter correctly.

   If bloom filter does not exist, return value does not matter because
   RocksDB does not use bloom filter internally.

  @param kd
  @param eq_cond      Equal condition part of the key. This always includes
                      system index id (4 bytes).
  @param use_all_keys True if all key parts are set with equal conditions.
                      This is aware of extended keys.
*/
bool can_use_bloom_filter(THD *thd, const Rdb_key_def &kd,
                          const rocksdb::Slice &eq_cond,
                          const bool use_all_keys, bool is_ascending) {
  bool can_use = false;

  if (THDVAR(thd, skip_bloom_filter_on_read)) {
    return can_use;
  }

  const rocksdb::SliceTransform *prefix_extractor = kd.get_extractor();
  if (prefix_extractor) {
    /*
      This is an optimized use case for CappedPrefixTransform.
      If eq_cond length >= prefix extractor length and if
      all keys are used for equal lookup, it is
      always possible to use bloom filter.

      Prefix bloom filter can't be used on descending scan with
      prefix lookup (i.e. WHERE id1=1 ORDER BY id2 DESC), because of
      RocksDB's limitation. On ascending (or not sorting) scan,
      keys longer than the capped prefix length will be truncated down
      to the capped length and the resulting key is added to the bloom filter.

      Keys shorter than the capped prefix length will be added to
      the bloom filter. When keys are looked up, key conditionals
      longer than the capped length can be used; key conditionals
      shorter require all parts of the key to be available
      for the short key match.
    */
    if (use_all_keys && prefix_extractor->InRange(eq_cond))
      can_use = true;
    else if (!is_ascending)
      can_use = false;
    else if (prefix_extractor->SameResultWhenAppended(eq_cond))
      can_use = true;
    else
      can_use = false;
  } else {
    /*
      if prefix extractor is not defined, all key parts have to be
      used by eq_cond.
    */
    if (use_all_keys)
      can_use = true;
    else
      can_use = false;
  }

  return can_use;
}

/* For modules that need access to the global data structures */
rocksdb::TransactionDB *rdb_get_rocksdb_db() { return rdb; }

Rdb_cf_manager &rdb_get_cf_manager() { return cf_manager; }

rocksdb::BlockBasedTableOptions &rdb_get_table_options() {
  return rocksdb_tbl_options;
}

int rdb_get_table_perf_counters(const char *const tablename,
                                Rdb_perf_counters *const counters) {
  DBUG_ASSERT(counters != nullptr);
  DBUG_ASSERT(tablename != nullptr);

  Rdb_table_handler *table_handler;
  table_handler = rdb_open_tables.get_table_handler(tablename);
  if (table_handler == nullptr) {
    return HA_ERR_INTERNAL_ERROR;
  }

  counters->load(table_handler->m_table_perf_context);

  rdb_open_tables.release_table_handler(table_handler);
  return HA_EXIT_SUCCESS;
}

void rdb_handle_io_error(rocksdb::Status status, RDB_IO_ERROR_TYPE err_type) {
  if (status.IsIOError()) {
    switch (err_type) {
    case RDB_IO_ERROR_TX_COMMIT:
    case RDB_IO_ERROR_DICT_COMMIT: {
      sql_print_error("RocksDB: Failed to write to WAL - status %d, %s",
                      status.code(), status.ToString().c_str());
      sql_print_error("RocksDB: Aborting on WAL write error.");
      abort_with_stack_traces();
      break;
    }
    case RDB_IO_ERROR_BG_THREAD: {
      sql_print_warning("RocksDB: BG Thread failed to write to RocksDB "
                        "- status %d, %s",
                        status.code(), status.ToString().c_str());
      break;
    }
    case RDB_IO_ERROR_GENERAL: {
      sql_print_error("RocksDB: Failed on I/O - status %d, %s", status.code(),
                      status.ToString().c_str());
      sql_print_error("RocksDB: Aborting on I/O error.");
      abort_with_stack_traces();
      break;
    }
    default:
      DBUG_ASSERT(0);
      break;
    }
  } else if (status.IsCorruption()) {
    /* NO_LINT_DEBUG */
    sql_print_error("RocksDB: Data Corruption detected! %d, %s", status.code(),
                    status.ToString().c_str());
    /* NO_LINT_DEBUG */
    sql_print_error("RocksDB: Aborting because of data corruption.");
    abort_with_stack_traces();
  } else if (!status.ok()) {
    switch (err_type) {
    case RDB_IO_ERROR_DICT_COMMIT: {
      sql_print_error("RocksDB: Failed to write to WAL (dictionary) - "
                      "status %d, %s",
                      status.code(), status.ToString().c_str());
      sql_print_error("RocksDB: Aborting on WAL write error.");
      abort_with_stack_traces();
      break;
    }
    default:
      sql_print_warning("RocksDB: Failed to read/write in RocksDB "
                        "- status %d, %s",
                        status.code(), status.ToString().c_str());
      break;
    }
  }
}

Rdb_dict_manager *rdb_get_dict_manager(void) { return &dict_manager; }

Rdb_ddl_manager *rdb_get_ddl_manager(void) { return &ddl_manager; }

void rocksdb_set_compaction_options(my_core::THD *const thd
                                    __attribute__((__unused__)),
                                    my_core::st_mysql_sys_var *const var
                                    __attribute__((__unused__)),
                                    void *const var_ptr,
                                    const void *const save) {
  if (var_ptr && save) {
    *(uint64_t *)var_ptr = *(const uint64_t *)save;
  }
  const Rdb_compact_params params = {
      (uint64_t)rocksdb_compaction_sequential_deletes,
      (uint64_t)rocksdb_compaction_sequential_deletes_window,
      (uint64_t)rocksdb_compaction_sequential_deletes_file_size};
  if (properties_collector_factory) {
    properties_collector_factory->SetCompactionParams(params);
  }
}

void rocksdb_set_table_stats_sampling_pct(
    my_core::THD *const thd __attribute__((__unused__)),
    my_core::st_mysql_sys_var *const var __attribute__((__unused__)),
    void *const var_ptr __attribute__((__unused__)), const void *const save) {
  mysql_mutex_lock(&rdb_sysvars_mutex);

  const uint32_t new_val = *static_cast<const uint32_t *>(save);

  if (new_val != rocksdb_table_stats_sampling_pct) {
    rocksdb_table_stats_sampling_pct = new_val;

    if (properties_collector_factory) {
      properties_collector_factory->SetTableStatsSamplingPct(
          rocksdb_table_stats_sampling_pct);
    }
  }

  mysql_mutex_unlock(&rdb_sysvars_mutex);
}

/*
  This function allows setting the rate limiter's bytes per second value
  but only if the rate limiter is turned on which has to be done at startup.
  If the rate is already 0 (turned off) or we are changing it to 0 (trying
  to turn it off) this function will push a warning to the client and do
  nothing.
  This is similar to the code in innodb_doublewrite_update (found in
  storage/innobase/handler/ha_innodb.cc).
*/
void rocksdb_set_rate_limiter_bytes_per_sec(my_core::THD *const thd,
                                            my_core::st_mysql_sys_var *const var
                                            __attribute__((__unused__)),
                                            void *const var_ptr
                                            __attribute__((__unused__)),
                                            const void *const save) {
  const uint64_t new_val = *static_cast<const uint64_t *>(save);
  if (new_val == 0 || rocksdb_rate_limiter_bytes_per_sec == 0) {
    /*
      If a rate_limiter was not enabled at startup we can't change it nor
      can we disable it if one was created at startup
    */
    push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN, ER_WRONG_ARGUMENTS,
                        "RocksDB: rocksdb_rate_limiter_bytes_per_sec cannot "
                        "be dynamically changed to or from 0.  Do a clean "
                        "shutdown if you want to change it from or to 0.");
  } else if (new_val != rocksdb_rate_limiter_bytes_per_sec) {
    /* Apply the new value to the rate limiter and store it locally */
    DBUG_ASSERT(rocksdb_rate_limiter != nullptr);
    rocksdb_rate_limiter_bytes_per_sec = new_val;
    rocksdb_rate_limiter->SetBytesPerSecond(new_val);
  }
}

void rdb_set_collation_exception_list(const char *const exception_list) {
  DBUG_ASSERT(rdb_collation_exceptions != nullptr);

  int flags = MY_REG_EXTENDED | MY_REG_NOSUB;
  if (lower_case_table_names)
    flags |= MY_REG_ICASE;
  if (!rdb_collation_exceptions->compile(
          exception_list, flags, table_alias_charset)) {
    warn_about_bad_patterns(*rdb_collation_exceptions,
                            "strict_collation_exceptions");
  }
}

void rocksdb_set_collation_exception_list(THD *const thd,
                                          struct st_mysql_sys_var *const var,
                                          void *const var_ptr,
                                          const void *const save) {
  const char *const val = *static_cast<const char *const *>(save);

  rdb_set_collation_exception_list(val);

  *static_cast<const char **>(var_ptr) = val;
}

void rocksdb_set_bulk_load(THD *const thd, struct st_mysql_sys_var *const var
                           __attribute__((__unused__)),
                           void *const var_ptr, const void *const save) {
  Rdb_transaction *&tx = get_tx_from_thd(thd);

  if (tx != nullptr) {
    const int rc = tx->finish_bulk_load();
    if (rc != 0) {
      // NO_LINT_DEBUG
      sql_print_error("RocksDB: Error %d finalizing last SST file while "
                      "setting bulk loading variable",
                      rc);
      abort_with_stack_traces();
    }
  }

  *static_cast<bool *>(var_ptr) = *static_cast<const bool *>(save);
}

static void rocksdb_set_max_background_compactions(
    THD *thd, struct st_mysql_sys_var *const var, void *const var_ptr,
    const void *const save) {
  DBUG_ASSERT(save != nullptr);

  mysql_mutex_lock(&rdb_sysvars_mutex);
  rocksdb_db_options.max_background_compactions =
      *static_cast<const int *>(save);
  rocksdb_db_options.env->SetBackgroundThreads(
      rocksdb_db_options.max_background_compactions,
      rocksdb::Env::Priority::LOW);
  mysql_mutex_unlock(&rdb_sysvars_mutex);
}

void rdb_queue_save_stats_request() { rdb_bg_thread.request_save_stats(); }

void ha_rocksdb::rpl_before_delete_rows() {
  DBUG_ENTER_FUNC();

  m_in_rpl_delete_rows = true;

  DBUG_VOID_RETURN;
}

void ha_rocksdb::rpl_after_delete_rows() {
  DBUG_ENTER_FUNC();

  m_in_rpl_delete_rows = false;

  DBUG_VOID_RETURN;
}

void ha_rocksdb::rpl_before_update_rows() {
  DBUG_ENTER_FUNC();

  m_in_rpl_update_rows = true;

  DBUG_VOID_RETURN;
}

void ha_rocksdb::rpl_after_update_rows() {
  DBUG_ENTER_FUNC();

  m_in_rpl_update_rows = false;

  DBUG_VOID_RETURN;
}

/**
  @brief
  Read Free Replication can be used or not. Returning False means
  Read Free Replication can be used. Read Free Replication can be used
  on UPDATE or DELETE row events, and table must have user defined
  primary key.
*/
bool ha_rocksdb::use_read_free_rpl() {
  DBUG_ENTER_FUNC();

  DBUG_RETURN((m_in_rpl_delete_rows || m_in_rpl_update_rows) &&
              !has_hidden_pk(table) && m_use_read_free_rpl);
}

double ha_rocksdb::read_time(uint index, uint ranges, ha_rows rows) {
  DBUG_ENTER_FUNC();

  if (index != table->s->primary_key) {
    /* Non covering index range scan */
    DBUG_RETURN(handler::read_time(index, ranges, rows));
  }

  DBUG_RETURN((rows / 20.0) + 1);
}

} // namespace myrocks

/*
  Register the storage engine plugin outside of myrocks namespace
  so that mysql_declare_plugin does not get confused when it does
  its name generation.
*/

struct st_mysql_storage_engine rocksdb_storage_engine = {
    MYSQL_HANDLERTON_INTERFACE_VERSION};

mysql_declare_plugin(rocksdb_se){
    MYSQL_STORAGE_ENGINE_PLUGIN,       /* Plugin Type */
    &rocksdb_storage_engine,           /* Plugin Descriptor */
    "ROCKSDB",                         /* Plugin Name */
    "Monty Program Ab",                /* Plugin Author */
    "RocksDB storage engine",          /* Plugin Description */
    PLUGIN_LICENSE_GPL,                /* Plugin Licence */
    myrocks::rocksdb_init_func,        /* Plugin Entry Point */
    myrocks::rocksdb_done_func,        /* Plugin Deinitializer */
    0x0001,                            /* version number (0.1) */
    myrocks::rocksdb_status_vars,      /* status variables */
    myrocks::rocksdb_system_variables, /* system variables */
    nullptr,                           /* config options */
    0,                                 /* flags */
},
    myrocks::rdb_i_s_cfstats, myrocks::rdb_i_s_dbstats,
    myrocks::rdb_i_s_perf_context, myrocks::rdb_i_s_perf_context_global,
    myrocks::rdb_i_s_cfoptions, myrocks::rdb_i_s_compact_stats,
    myrocks::rdb_i_s_global_info, myrocks::rdb_i_s_ddl,
    myrocks::rdb_i_s_index_file_map, myrocks::rdb_i_s_lock_info,
    myrocks::rdb_i_s_trx_info mysql_declare_plugin_end;