storage/perfschema/table_events_waits.cc

/* Copyright (c) 2008, 2021, Oracle and/or its affiliates.

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License, version 2.0,
  as published by the Free Software Foundation.

  This program is also distributed with certain software (including
  but not limited to OpenSSL) that is licensed under separate terms,
  as designated in a particular file or component or in included license
  documentation.  The authors of MySQL hereby grant you an additional
  permission to link the program and your derivative works with the
  separately licensed software that they have included with MySQL.

  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, version 2.0, 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,
  51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */

/**
  @file storage/perfschema/table_events_waits.cc
  Table EVENTS_WAITS_xxx (implementation).
*/

#include "my_global.h"
#include "my_thread.h"
#include "table_events_waits.h"
#include "pfs_global.h"
#include "pfs_instr_class.h"
#include "pfs_instr.h"
#include "pfs_events_waits.h"
#include "pfs_timer.h"
#include "m_string.h"
#include "pfs_buffer_container.h"
#include "field.h"

THR_LOCK table_events_waits_current::m_table_lock;

static const TABLE_FIELD_TYPE field_types[]=
{
  {
    { C_STRING_WITH_LEN("THREAD_ID") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("EVENT_ID") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("END_EVENT_ID") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("EVENT_NAME") },
    { C_STRING_WITH_LEN("varchar(128)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("SOURCE") },
    { C_STRING_WITH_LEN("varchar(64)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("TIMER_START") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("TIMER_END") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("TIMER_WAIT") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("SPINS") },
    { C_STRING_WITH_LEN("int(10)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("OBJECT_SCHEMA") },
    { C_STRING_WITH_LEN("varchar(64)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("OBJECT_NAME") },
    { C_STRING_WITH_LEN("varchar(512)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("INDEX_NAME") },
    { C_STRING_WITH_LEN("varchar(64)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("OBJECT_TYPE") },
    { C_STRING_WITH_LEN("varchar(64)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("OBJECT_INSTANCE_BEGIN") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("NESTING_EVENT_ID") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("NESTING_EVENT_TYPE") },
    { C_STRING_WITH_LEN("enum(\'TRANSACTION\',\'STATEMENT\',\'STAGE\',\'WAIT\'") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("OPERATION") },
    { C_STRING_WITH_LEN("varchar(32)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("NUMBER_OF_BYTES") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("FLAGS") },
    { C_STRING_WITH_LEN("int(10)") },
    { NULL, 0}
  }
};

TABLE_FIELD_DEF
table_events_waits_current::m_field_def=
{ 19, field_types };

PFS_engine_table_share
table_events_waits_current::m_share=
{
  { C_STRING_WITH_LEN("events_waits_current") },
  &pfs_truncatable_acl,
  table_events_waits_current::create,
  NULL, /* write_row */
  table_events_waits_current::delete_all_rows,
  table_events_waits_current::get_row_count,
  sizeof(pos_events_waits_current), /* ref length */
  &m_table_lock,
  &m_field_def,
  false, /* checked */
  false  /* perpetual */
};

THR_LOCK table_events_waits_history::m_table_lock;

PFS_engine_table_share
table_events_waits_history::m_share=
{
  { C_STRING_WITH_LEN("events_waits_history") },
  &pfs_truncatable_acl,
  table_events_waits_history::create,
  NULL, /* write_row */
  table_events_waits_history::delete_all_rows,
  table_events_waits_history::get_row_count,
  sizeof(pos_events_waits_history), /* ref length */
  &m_table_lock,
  &table_events_waits_current::m_field_def,
  false, /* checked */
  false  /* perpetual */
};

THR_LOCK table_events_waits_history_long::m_table_lock;

PFS_engine_table_share
table_events_waits_history_long::m_share=
{
  { C_STRING_WITH_LEN("events_waits_history_long") },
  &pfs_truncatable_acl,
  table_events_waits_history_long::create,
  NULL, /* write_row */
  table_events_waits_history_long::delete_all_rows,
  table_events_waits_history_long::get_row_count,
  sizeof(PFS_simple_index), /* ref length */
  &m_table_lock,
  &table_events_waits_current::m_field_def,
  false, /* checked */
  false  /* perpetual */
};

table_events_waits_common::table_events_waits_common
(const PFS_engine_table_share *share, void *pos)
  : PFS_engine_table(share, pos),
  m_row_exists(false)
{}

void table_events_waits_common::clear_object_columns()
{
  m_row.m_object_type_length= 0;
  m_row.m_object_schema_length= 0;
  m_row.m_object_name_length= 0;
  m_row.m_index_name_length= 0;
}

int table_events_waits_common::make_table_object_columns(PFS_events_waits *wait)
{
  uint safe_index;
  PFS_table_share *safe_table_share;

  safe_table_share= sanitize_table_share(wait->m_weak_table_share);
  if (unlikely(safe_table_share == NULL))
    return 1;

  if (wait->m_object_type == OBJECT_TYPE_TABLE)
  {
    m_row.m_object_type= "TABLE";
    m_row.m_object_type_length= 5;
  }
  else
  {
    m_row.m_object_type= "TEMPORARY TABLE";
    m_row.m_object_type_length= 15;
  }

  if (safe_table_share->get_version() == wait->m_weak_version)
  {
    /* OBJECT SCHEMA */
    m_row.m_object_schema_length= safe_table_share->m_schema_name_length;
    if (unlikely((m_row.m_object_schema_length == 0) ||
                 (m_row.m_object_schema_length > sizeof(m_row.m_object_schema))))
      return 1;
    memcpy(m_row.m_object_schema, safe_table_share->m_schema_name, m_row.m_object_schema_length);

    /* OBJECT NAME */
    m_row.m_object_name_length= safe_table_share->m_table_name_length;
    if (unlikely((m_row.m_object_name_length == 0) ||
                 (m_row.m_object_name_length > sizeof(m_row.m_object_name))))
      return 1;
    memcpy(m_row.m_object_name, safe_table_share->m_table_name, m_row.m_object_name_length);

    /* INDEX NAME */
    safe_index= wait->m_index;
    uint safe_key_count= sanitize_index_count(safe_table_share->m_key_count);
    if (safe_index < safe_key_count)
    {
      PFS_table_share_index *index_stat;
      index_stat= safe_table_share->find_index_stat(safe_index);

      if (index_stat != NULL)
      {
        m_row.m_index_name_length= index_stat->m_key.m_name_length;

        if (unlikely((m_row.m_index_name_length == 0) ||
                     (m_row.m_index_name_length > sizeof(m_row.m_index_name))))
          return 1;

        memcpy(m_row.m_index_name, index_stat->m_key.m_name, m_row.m_index_name_length);
      }
      else
      {
        m_row.m_index_name_length= 0;
      }
    }
    else
    {
      m_row.m_index_name_length= 0;
    }
  }
  else
  {
    m_row.m_object_schema_length= 0;
    m_row.m_object_name_length= 0;
    m_row.m_index_name_length= 0;
  }

  m_row.m_object_instance_addr= (intptr) wait->m_object_instance_addr;
  return 0;
}

int table_events_waits_common::make_file_object_columns(PFS_events_waits *wait)
{
  PFS_file *safe_file;

  safe_file= sanitize_file(wait->m_weak_file);
  if (unlikely(safe_file == NULL))
    return 1;

  m_row.m_object_type= "FILE";
  m_row.m_object_type_length= 4;
  m_row.m_object_schema_length= 0;
  m_row.m_object_instance_addr= (intptr) wait->m_object_instance_addr;

  if (safe_file->get_version() == wait->m_weak_version)
  {
    /* OBJECT NAME */
    m_row.m_object_name_length= safe_file->m_filename_length;
    if (unlikely((m_row.m_object_name_length == 0) ||
                 (m_row.m_object_name_length > sizeof(m_row.m_object_name))))
      return 1;
    memcpy(m_row.m_object_name, safe_file->m_filename, m_row.m_object_name_length);
  }
  else
  {
    m_row.m_object_name_length= 0;
  }

  m_row.m_index_name_length= 0;

  return 0;
}

int table_events_waits_common::make_socket_object_columns(PFS_events_waits *wait)
{
  PFS_socket *safe_socket;

  safe_socket= sanitize_socket(wait->m_weak_socket);
  if (unlikely(safe_socket == NULL))
    return 1;

  m_row.m_object_type= "SOCKET";
  m_row.m_object_type_length= 6;
  m_row.m_object_schema_length= 0;
  m_row.m_object_instance_addr= (intptr) wait->m_object_instance_addr;

  if (safe_socket->get_version() == wait->m_weak_version)
  {
    /* Convert port number to string, include delimiter in port name length */

    uint port;
    char port_str[128];
    char ip_str[INET6_ADDRSTRLEN+1];
    uint ip_len= 0;
    port_str[0]= ':';

    /* Get the IP address and port number */
    ip_len= pfs_get_socket_address(ip_str, sizeof(ip_str), &port,
                                   &safe_socket->m_sock_addr,
                                   safe_socket->m_addr_len);

    /* Convert port number to a string (length includes ':') */
    size_t port_len= int10_to_str(port, (port_str+1), 10) - port_str + 1;

    /* OBJECT NAME */
    m_row.m_object_name_length= ip_len + port_len;

    if (unlikely((m_row.m_object_name_length == 0) ||
                 (m_row.m_object_name_length > sizeof(m_row.m_object_name))))
      return 1;

    char *name= m_row.m_object_name;
    memcpy(name, ip_str, ip_len);
    memcpy(name + ip_len, port_str, port_len);
  }
  else
  {
    m_row.m_object_name_length= 0;
  }

  m_row.m_index_name_length= 0;

  return 0;
}

int table_events_waits_common::make_metadata_lock_object_columns(PFS_events_waits *wait)
{
  PFS_metadata_lock *safe_metadata_lock;

  safe_metadata_lock= sanitize_metadata_lock(wait->m_weak_metadata_lock);
  if (unlikely(safe_metadata_lock == NULL))
    return 1;

  if (safe_metadata_lock->get_version() == wait->m_weak_version)
  {
    MDL_key *mdl= & safe_metadata_lock->m_mdl_key;

    switch(mdl->mdl_namespace())
    {
    case MDL_key::GLOBAL:
      m_row.m_object_type= "GLOBAL";
      m_row.m_object_type_length= 6;
      m_row.m_object_schema_length= 0;
      m_row.m_object_name_length= 0;
      break;
    case MDL_key::SCHEMA:
      m_row.m_object_type= "SCHEMA";
      m_row.m_object_type_length= 6;
      m_row.m_object_schema_length= mdl->db_name_length();
      m_row.m_object_name_length= 0;
      break;
    case MDL_key::TABLE:
      m_row.m_object_type= "TABLE";
      m_row.m_object_type_length= 5;
      m_row.m_object_schema_length= mdl->db_name_length();
      m_row.m_object_name_length= mdl->name_length();
      break;
    case MDL_key::FUNCTION:
      m_row.m_object_type= "FUNCTION";
      m_row.m_object_type_length= 8;
      m_row.m_object_schema_length= mdl->db_name_length();
      m_row.m_object_name_length= mdl->name_length();
      break;
    case MDL_key::PROCEDURE:
      m_row.m_object_type= "PROCEDURE";
      m_row.m_object_type_length= 9;
      m_row.m_object_schema_length= mdl->db_name_length();
      m_row.m_object_name_length= mdl->name_length();
      break;
    case MDL_key::TRIGGER:
      m_row.m_object_type= "TRIGGER";
      m_row.m_object_type_length= 7;
      m_row.m_object_schema_length= mdl->db_name_length();
      m_row.m_object_name_length= mdl->name_length();
      break;
    case MDL_key::EVENT:
      m_row.m_object_type= "EVENT";
      m_row.m_object_type_length= 5;
      m_row.m_object_schema_length= mdl->db_name_length();
      m_row.m_object_name_length= mdl->name_length();
      break;
    case MDL_key::COMMIT:
      m_row.m_object_type= "COMMIT";
      m_row.m_object_type_length= 6;
      m_row.m_object_schema_length= 0;
      m_row.m_object_name_length= 0;
      break;
    case MDL_key::USER_LEVEL_LOCK:
      m_row.m_object_type= "USER LEVEL LOCK";
      m_row.m_object_type_length= 15;
      m_row.m_object_schema_length= 0;
      m_row.m_object_name_length= mdl->name_length();
      break;
    case MDL_key::TABLESPACE:
      m_row.m_object_type= "TABLESPACE";
      m_row.m_object_type_length= 10;
      m_row.m_object_schema_length= 0;
      m_row.m_object_name_length= mdl->name_length();
      break;
    case MDL_key::LOCKING_SERVICE:
      m_row.m_object_type= "LOCKING SERVICE";
      m_row.m_object_type_length= 15;
      m_row.m_object_schema_length= mdl->db_name_length();
      m_row.m_object_name_length= mdl->name_length();
      break;
    case MDL_key::NAMESPACE_END:
    default:
      m_row.m_object_type_length= 0;
      m_row.m_object_schema_length= 0;
      m_row.m_object_name_length= 0;
      break;
    }

    if (m_row.m_object_schema_length > sizeof(m_row.m_object_schema))
      return 1;
    if (m_row.m_object_schema_length > 0)
      memcpy(m_row.m_object_schema, mdl->db_name(), m_row.m_object_schema_length);

    if (m_row.m_object_name_length > sizeof(m_row.m_object_name))
      return 1;
    if (m_row.m_object_name_length > 0)
      memcpy(m_row.m_object_name, mdl->name(), m_row.m_object_name_length);

    m_row.m_object_instance_addr= (intptr) wait->m_object_instance_addr;
  }
  else
  {
    m_row.m_object_type_length= 0;
    m_row.m_object_schema_length= 0;
    m_row.m_object_name_length= 0;
    m_row.m_object_instance_addr= 0;
  }

  /* INDEX NAME */
  m_row.m_index_name_length= 0;

  return 0;
}

/**
  Build a row.
  @param wait                       the wait the cursor is reading
*/
void table_events_waits_common::make_row(PFS_events_waits *wait)
{
  PFS_instr_class *safe_class;
  enum_timer_name timer_name= wait_timer;
  ulonglong timer_end;

  m_row_exists= false;

  /*
    Design choice:
    We could have used a pfs_lock in PFS_events_waits here,
    to protect the reader from concurrent event generation,
    but this leads to too many pfs_lock atomic operations
    each time an event is recorded:
    - 1 dirty() + 1 allocated() per event start, for EVENTS_WAITS_CURRENT
    - 1 dirty() + 1 allocated() per event end, for EVENTS_WAITS_CURRENT
    - 1 dirty() + 1 allocated() per copy to EVENTS_WAITS_HISTORY
    - 1 dirty() + 1 allocated() per copy to EVENTS_WAITS_HISTORY_LONG
    or 8 atomics per recorded event.
    The problem is that we record a *lot* of events ...

    This code is prepared to accept *dirty* records,
    and sanitizes all the data before returning a row.
  */

  /*
    PFS_events_waits::m_class needs to be sanitized,
    for race conditions when this code:
    - reads a new value in m_wait_class,
    - reads an old value in m_class.
  */
  switch (wait->m_wait_class)
  {
  case WAIT_CLASS_METADATA:
    if (make_metadata_lock_object_columns(wait))
      return;
    safe_class= sanitize_metadata_class(wait->m_class);
    break;
  case WAIT_CLASS_IDLE:
    clear_object_columns();
    m_row.m_object_instance_addr= 0;
    safe_class= sanitize_idle_class(wait->m_class);
    timer_name= idle_timer;
    break;
  case WAIT_CLASS_MUTEX:
    clear_object_columns();
    m_row.m_object_instance_addr= (intptr) wait->m_object_instance_addr;
    safe_class= sanitize_mutex_class((PFS_mutex_class*) wait->m_class);
    break;
  case WAIT_CLASS_RWLOCK:
    clear_object_columns();
    m_row.m_object_instance_addr= (intptr) wait->m_object_instance_addr;
    safe_class= sanitize_rwlock_class((PFS_rwlock_class*) wait->m_class);
    break;
  case WAIT_CLASS_COND:
    clear_object_columns();
    m_row.m_object_instance_addr= (intptr) wait->m_object_instance_addr;
    safe_class= sanitize_cond_class((PFS_cond_class*) wait->m_class);
    break;
  case WAIT_CLASS_TABLE:
    if (make_table_object_columns(wait))
      return;
    safe_class= sanitize_table_class(wait->m_class);
    break;
  case WAIT_CLASS_FILE:
    if (make_file_object_columns(wait))
      return;
    safe_class= sanitize_file_class((PFS_file_class*) wait->m_class);
    break;
  case WAIT_CLASS_SOCKET:
    if (make_socket_object_columns(wait))
      return;
    safe_class= sanitize_socket_class((PFS_socket_class*) wait->m_class);
    break;
  case NO_WAIT_CLASS:
  default:
    return;
  }

  if (unlikely(safe_class == NULL))
    return;

  m_row.m_thread_internal_id= wait->m_thread_internal_id;
  m_row.m_event_id= wait->m_event_id;
  m_row.m_end_event_id= wait->m_end_event_id;
  m_row.m_nesting_event_id= wait->m_nesting_event_id;
  m_row.m_nesting_event_type= wait->m_nesting_event_type;

  get_normalizer(safe_class);

  if (m_row.m_end_event_id == 0)
  {
    timer_end= get_timer_raw_value(timer_name);
  }
  else
  {
    timer_end= wait->m_timer_end;
  }

  m_normalizer->to_pico(wait->m_timer_start, timer_end,
                      & m_row.m_timer_start, & m_row.m_timer_end, & m_row.m_timer_wait);

  m_row.m_name= safe_class->m_name;
  m_row.m_name_length= safe_class->m_name_length;

  /* Disable source file and line to avoid stale __FILE__ pointers. */
  m_row.m_source_length= 0;

  m_row.m_operation= wait->m_operation;
  m_row.m_number_of_bytes= wait->m_number_of_bytes;
  m_row.m_flags= wait->m_flags;

  m_row_exists= true;
}

/**
  Operations names map, as displayed in the 'OPERATION' column.
  Indexed by enum_operation_type - 1.
  Note: enum_operation_type contains a more precise definition,
  since more details are needed internally by the instrumentation.
  Different similar operations (CLOSE vs STREAMCLOSE) are displayed
  with the same name 'close'.
*/
static const LEX_STRING operation_names_map[]=
{
  /* Mutex operations */
  { C_STRING_WITH_LEN("lock") },
  { C_STRING_WITH_LEN("try_lock") },

  /* RWLock operations (RW-lock) */
  { C_STRING_WITH_LEN("read_lock") },
  { C_STRING_WITH_LEN("write_lock") },
  { C_STRING_WITH_LEN("try_read_lock") },
  { C_STRING_WITH_LEN("try_write_lock") },

  /* RWLock operations (SX-lock) */
  { C_STRING_WITH_LEN("shared_lock") },
  { C_STRING_WITH_LEN("shared_exclusive_lock") },
  { C_STRING_WITH_LEN("exclusive_lock") },
  { C_STRING_WITH_LEN("try_shared_lock") },
  { C_STRING_WITH_LEN("try_shared_exclusive_lock") },
  { C_STRING_WITH_LEN("try_exclusive_lock") },

  /* Condition operations */
  { C_STRING_WITH_LEN("wait") },
  { C_STRING_WITH_LEN("timed_wait") },

  /* File operations */
  { C_STRING_WITH_LEN("create") },
  { C_STRING_WITH_LEN("create") }, /* create tmp */
  { C_STRING_WITH_LEN("open") },
  { C_STRING_WITH_LEN("open") }, /* stream open */
  { C_STRING_WITH_LEN("close") },
  { C_STRING_WITH_LEN("close") }, /* stream close */
  { C_STRING_WITH_LEN("read") },
  { C_STRING_WITH_LEN("write") },
  { C_STRING_WITH_LEN("seek") },
  { C_STRING_WITH_LEN("tell") },
  { C_STRING_WITH_LEN("flush") },
  { C_STRING_WITH_LEN("stat") },
  { C_STRING_WITH_LEN("stat") }, /* fstat */
  { C_STRING_WITH_LEN("chsize") },
  { C_STRING_WITH_LEN("delete") },
  { C_STRING_WITH_LEN("rename") },
  { C_STRING_WITH_LEN("sync") },

  /* Table io operations */
  { C_STRING_WITH_LEN("fetch") },
  { C_STRING_WITH_LEN("insert") }, /* write row */
  { C_STRING_WITH_LEN("update") }, /* update row */
  { C_STRING_WITH_LEN("delete") }, /* delete row */

  /* Table lock operations */
  { C_STRING_WITH_LEN("read normal") },
  { C_STRING_WITH_LEN("read with shared locks") },
  { C_STRING_WITH_LEN("read high priority") },
  { C_STRING_WITH_LEN("read no inserts") },
  { C_STRING_WITH_LEN("write allow write") },
  { C_STRING_WITH_LEN("write concurrent insert") },
  { C_STRING_WITH_LEN("write low priority") },
  { C_STRING_WITH_LEN("write normal") },
  { C_STRING_WITH_LEN("read external") },
  { C_STRING_WITH_LEN("write external") },

  /* Socket operations */
  { C_STRING_WITH_LEN("create") },
  { C_STRING_WITH_LEN("connect") },
  { C_STRING_WITH_LEN("bind") },
  { C_STRING_WITH_LEN("close") },
  { C_STRING_WITH_LEN("send") },
  { C_STRING_WITH_LEN("recv") },
  { C_STRING_WITH_LEN("sendto") },
  { C_STRING_WITH_LEN("recvfrom") },
  { C_STRING_WITH_LEN("sendmsg") },
  { C_STRING_WITH_LEN("recvmsg") },
  { C_STRING_WITH_LEN("seek") },
  { C_STRING_WITH_LEN("opt") },
  { C_STRING_WITH_LEN("stat") },
  { C_STRING_WITH_LEN("shutdown") },
  { C_STRING_WITH_LEN("select") },

  /* Idle operations */
  { C_STRING_WITH_LEN("idle") },

  /* Medatada lock operations */
  { C_STRING_WITH_LEN("metadata lock") }
};


int table_events_waits_common::read_row_values(TABLE *table,
                                               unsigned char *buf,
                                               Field **fields,
                                               bool read_all)
{
  Field *f;
  const LEX_STRING *operation;

  compile_time_assert(COUNT_OPERATION_TYPE ==
                      array_elements(operation_names_map));

  if (unlikely(! m_row_exists))
    return HA_ERR_RECORD_DELETED;

  /* Set the null bits */
  assert(table->s->null_bytes == 2);
  buf[0]= 0;
  buf[1]= 0;

  /*
    Some columns are unreliable, because they are joined with other buffers,
    which could have changed and been reused for something else.
    These columns are:
    - THREAD_ID (m_thread joins with PFS_thread),
    - SCHEMA_NAME (m_schema_name joins with PFS_table_share)
    - OBJECT_NAME (m_object_name joins with PFS_table_share)
  */
  for (; (f= *fields) ; fields++)
  {
    if (read_all || bitmap_is_set(table->read_set, f->field_index))
    {
      switch(f->field_index)
      {
      case 0: /* THREAD_ID */
        set_field_ulonglong(f, m_row.m_thread_internal_id);
        break;
      case 1: /* EVENT_ID */
        set_field_ulonglong(f, m_row.m_event_id);
        break;
      case 2: /* END_EVENT_ID */
        if (m_row.m_end_event_id > 0)
          set_field_ulonglong(f, m_row.m_end_event_id - 1);
        else
          f->set_null();
        break;
      case 3: /* EVENT_NAME */
        set_field_varchar_utf8(f, m_row.m_name, m_row.m_name_length);
        break;
      case 4: /* SOURCE */
        set_field_varchar_utf8(f, m_row.m_source, m_row.m_source_length);
        break;
      case 5: /* TIMER_START */
        if (m_row.m_timer_start != 0)
          set_field_ulonglong(f, m_row.m_timer_start);
        else
          f->set_null();
        break;
      case 6: /* TIMER_END */
        if (m_row.m_timer_end != 0)
          set_field_ulonglong(f, m_row.m_timer_end);
        else
          f->set_null();
        break;
      case 7: /* TIMER_WAIT */
        if (m_row.m_timer_wait != 0)
          set_field_ulonglong(f, m_row.m_timer_wait);
        else
          f->set_null();
        break;
      case 8: /* SPINS */
        f->set_null();
        break;
      case 9: /* OBJECT_SCHEMA */
        if (m_row.m_object_schema_length > 0)
        {
          set_field_varchar_utf8(f, m_row.m_object_schema,
                                 m_row.m_object_schema_length);
        }
        else
          f->set_null();
        break;
      case 10: /* OBJECT_NAME */
        if (m_row.m_object_name_length > 0)
        {
          set_field_varchar_utf8(f, m_row.m_object_name,
                                 m_row.m_object_name_length);
        }
        else
          f->set_null();
        break;
      case 11: /* INDEX_NAME */
        if (m_row.m_index_name_length > 0)
        {
          set_field_varchar_utf8(f, m_row.m_index_name,
                                 m_row.m_index_name_length);
        }
        else
          f->set_null();
        break;
      case 12: /* OBJECT_TYPE */
        if (m_row.m_object_type_length > 0)
        {
          set_field_varchar_utf8(f, m_row.m_object_type,
                                 m_row.m_object_type_length);
        }
        else
          f->set_null();
        break;
      case 13: /* OBJECT_INSTANCE */
        set_field_ulonglong(f, m_row.m_object_instance_addr);
        break;
      case 14: /* NESTING_EVENT_ID */
        if (m_row.m_nesting_event_id != 0)
          set_field_ulonglong(f, m_row.m_nesting_event_id);
        else
          f->set_null();
        break;
      case 15: /* NESTING_EVENT_TYPE */
        if (m_row.m_nesting_event_id != 0)
          set_field_enum(f, m_row.m_nesting_event_type);
        else
          f->set_null();
        break;
      case 16: /* OPERATION */
        operation= &operation_names_map[(int) m_row.m_operation - 1];
        set_field_varchar_utf8(f, operation->str, operation->length);
        break;
      case 17: /* NUMBER_OF_BYTES (also used for ROWS) */
        if ((m_row.m_operation == OPERATION_TYPE_FILEREAD) ||
            (m_row.m_operation == OPERATION_TYPE_FILEWRITE) ||
            (m_row.m_operation == OPERATION_TYPE_FILECHSIZE) ||
            (m_row.m_operation == OPERATION_TYPE_SOCKETSEND) ||
            (m_row.m_operation == OPERATION_TYPE_SOCKETRECV) ||
            (m_row.m_operation == OPERATION_TYPE_SOCKETSENDTO) ||
            (m_row.m_operation == OPERATION_TYPE_SOCKETRECVFROM) ||
            (m_row.m_operation == OPERATION_TYPE_TABLE_FETCH) ||
            (m_row.m_operation == OPERATION_TYPE_TABLE_WRITE_ROW) ||
            (m_row.m_operation == OPERATION_TYPE_TABLE_UPDATE_ROW) ||
            (m_row.m_operation == OPERATION_TYPE_TABLE_DELETE_ROW))
          set_field_ulonglong(f, m_row.m_number_of_bytes);
        else
          f->set_null();
        break;
      case 18: /* FLAGS */
        f->set_null();
        break;
      default:
        assert(false);
      }
    }
  }
  return 0;
}

PFS_engine_table* table_events_waits_current::create(void)
{
  return new table_events_waits_current();
}

table_events_waits_current::table_events_waits_current()
  : table_events_waits_common(&m_share, &m_pos),
  m_pos(), m_next_pos()
{}

void table_events_waits_current::reset_position(void)
{
  m_pos.reset();
  m_next_pos.reset();
}

int table_events_waits_current::rnd_next(void)
{
  PFS_thread *pfs_thread;
  PFS_events_waits *wait;
  bool has_more_thread= true;

  for (m_pos.set_at(&m_next_pos);
       has_more_thread;
       m_pos.next_thread())
  {
    pfs_thread= global_thread_container.get(m_pos.m_index_1, & has_more_thread);
    if (pfs_thread != NULL)
    {
      /*
        We do not show nested events for now,
        this will be revised with TABLE io
      */
// #define ONLY_SHOW_ONE_WAIT

#ifdef ONLY_SHOW_ONE_WAIT
      if (m_pos.m_index_2 >= 1)
        continue;
#else
      /* m_events_waits_stack[0] is a dummy record */
      PFS_events_waits *top_wait = &pfs_thread->m_events_waits_stack[WAIT_STACK_BOTTOM];
      wait= &pfs_thread->m_events_waits_stack[m_pos.m_index_2 + WAIT_STACK_BOTTOM];

      PFS_events_waits *safe_current = pfs_thread->m_events_waits_current;

      if (safe_current == top_wait)
      {
        /* Display the last top level wait, when completed */
        if (m_pos.m_index_2 >= 1)
          continue;
      }
      else
      {
        /* Display all pending waits, when in progress */
        if (wait >= safe_current)
          continue;
      }
#endif

      if (wait->m_wait_class == NO_WAIT_CLASS)
      {
        /*
          This locker does not exist.
          There can not be more lockers in the stack, skip to the next thread
        */
        continue;
      }

      make_row(pfs_thread, wait);
      /* Next iteration, look for the next locker in this thread */
      m_next_pos.set_after(&m_pos);
      return 0;
    }
  }

  return HA_ERR_END_OF_FILE;
}

int table_events_waits_current::rnd_pos(const void *pos)
{
  PFS_thread *pfs_thread;
  PFS_events_waits *wait;

  set_position(pos);

  pfs_thread= global_thread_container.get(m_pos.m_index_1);
  if (pfs_thread != NULL)
  {
#ifdef ONLY_SHOW_ONE_WAIT
    if (m_pos.m_index_2 >= 1)
      return HA_ERR_RECORD_DELETED;
#else
    /* m_events_waits_stack[0] is a dummy record */
    PFS_events_waits *top_wait = &pfs_thread->m_events_waits_stack[WAIT_STACK_BOTTOM];
    wait= &pfs_thread->m_events_waits_stack[m_pos.m_index_2 + WAIT_STACK_BOTTOM];

    PFS_events_waits *safe_current = pfs_thread->m_events_waits_current;

    if (safe_current == top_wait)
    {
      /* Display the last top level wait, when completed */
      if (m_pos.m_index_2 >= 1)
        return HA_ERR_RECORD_DELETED;
    }
    else
    {
      /* Display all pending waits, when in progress */
      if (wait >= safe_current)
        return HA_ERR_RECORD_DELETED;
    }
#endif

    assert(m_pos.m_index_2 < WAIT_STACK_LOGICAL_SIZE);

    if (wait->m_wait_class != NO_WAIT_CLASS)
    {
      make_row(pfs_thread, wait);
      return 0;
    }
  }

  return HA_ERR_RECORD_DELETED;
}

void table_events_waits_current::make_row(PFS_thread *thread, PFS_events_waits *wait)
{
  pfs_optimistic_state lock;

  /* Protect this reader against a thread termination */
  thread->m_lock.begin_optimistic_lock(&lock);

  table_events_waits_common::make_row(wait);

  if (! thread->m_lock.end_optimistic_lock(&lock))
    m_row_exists= false;
}

int table_events_waits_current::delete_all_rows(void)
{
  reset_events_waits_current();
  return 0;
}

ha_rows
table_events_waits_current::get_row_count(void)
{
  return WAIT_STACK_SIZE * global_thread_container.get_row_count();
}

PFS_engine_table* table_events_waits_history::create(void)
{
  return new table_events_waits_history();
}

table_events_waits_history::table_events_waits_history()
  : table_events_waits_common(&m_share, &m_pos),
  m_pos(), m_next_pos()
{}

void table_events_waits_history::reset_position(void)
{
  m_pos.reset();
  m_next_pos.reset();
}

int table_events_waits_history::rnd_next(void)
{
  PFS_thread *pfs_thread;
  PFS_events_waits *wait;
  bool has_more_thread= true;

  if (events_waits_history_per_thread == 0)
    return HA_ERR_END_OF_FILE;

  for (m_pos.set_at(&m_next_pos);
       has_more_thread;
       m_pos.next_thread())
  {
    pfs_thread= global_thread_container.get(m_pos.m_index_1, & has_more_thread);
    if (pfs_thread != NULL)
    {
      if (m_pos.m_index_2 >= events_waits_history_per_thread)
      {
        /* This thread does not have more (full) history */
        continue;
      }

      if ( ! pfs_thread->m_waits_history_full &&
          (m_pos.m_index_2 >= pfs_thread->m_waits_history_index))
      {
        /* This thread does not have more (not full) history */
        continue;
      }

      wait= &pfs_thread->m_waits_history[m_pos.m_index_2];
      if (wait->m_wait_class != NO_WAIT_CLASS)
      {
        make_row(pfs_thread, wait);
        /* Next iteration, look for the next history in this thread */
        m_next_pos.set_after(&m_pos);
        return 0;
      }
    }
  }

  return HA_ERR_END_OF_FILE;
}

int table_events_waits_history::rnd_pos(const void *pos)
{
  PFS_thread *pfs_thread;
  PFS_events_waits *wait;

  assert(events_waits_history_per_thread != 0);
  set_position(pos);

  pfs_thread= global_thread_container.get(m_pos.m_index_1);
  if (pfs_thread != NULL)
  {
    assert(m_pos.m_index_2 < events_waits_history_per_thread);

    if ( ! pfs_thread->m_waits_history_full &&
        (m_pos.m_index_2 >= pfs_thread->m_waits_history_index))
      return HA_ERR_RECORD_DELETED;

    wait= &pfs_thread->m_waits_history[m_pos.m_index_2];

    if (wait->m_wait_class != NO_WAIT_CLASS)
    {
      make_row(pfs_thread, wait);
      return 0;
    }
  }

  return HA_ERR_RECORD_DELETED;
}

void table_events_waits_history::make_row(PFS_thread *thread, PFS_events_waits *wait)
{
  pfs_optimistic_state lock;

  /* Protect this reader against a thread termination */
  thread->m_lock.begin_optimistic_lock(&lock);

  table_events_waits_common::make_row(wait);

  if (! thread->m_lock.end_optimistic_lock(&lock))
    m_row_exists= false;
}

int table_events_waits_history::delete_all_rows(void)
{
  reset_events_waits_history();
  return 0;
}

ha_rows
table_events_waits_history::get_row_count(void)
{
  return events_waits_history_per_thread * global_thread_container.get_row_count();
}

PFS_engine_table* table_events_waits_history_long::create(void)
{
  return new table_events_waits_history_long();
}

table_events_waits_history_long::table_events_waits_history_long()
  : table_events_waits_common(&m_share, &m_pos),
  m_pos(0), m_next_pos(0)
{}

void table_events_waits_history_long::reset_position(void)
{
  m_pos.m_index= 0;
  m_next_pos.m_index= 0;
}

int table_events_waits_history_long::rnd_next(void)
{
  PFS_events_waits *wait;
  uint limit;

  if (events_waits_history_long_size == 0)
    return HA_ERR_END_OF_FILE;

  if (events_waits_history_long_full)
    limit= events_waits_history_long_size;
  else
    limit= events_waits_history_long_index.m_u32 % events_waits_history_long_size;

  for (m_pos.set_at(&m_next_pos); m_pos.m_index < limit; m_pos.next())
  {
    wait= &events_waits_history_long_array[m_pos.m_index];

    if (wait->m_wait_class != NO_WAIT_CLASS)
    {
      make_row(wait);
      /* Next iteration, look for the next entry */
      m_next_pos.set_after(&m_pos);
      return 0;
    }
  }

  return HA_ERR_END_OF_FILE;
}

int table_events_waits_history_long::rnd_pos(const void *pos)
{
  PFS_events_waits *wait;
  uint limit;

  if (events_waits_history_long_size == 0)
    return HA_ERR_RECORD_DELETED;

  set_position(pos);

  if (events_waits_history_long_full)
    limit= events_waits_history_long_size;
  else
    limit= events_waits_history_long_index.m_u32 % events_waits_history_long_size;

  if (m_pos.m_index >= limit)
    return HA_ERR_RECORD_DELETED;

  wait= &events_waits_history_long_array[m_pos.m_index];

  if (wait->m_wait_class == NO_WAIT_CLASS)
    return HA_ERR_RECORD_DELETED;

  make_row(wait);
  return 0;
}

int table_events_waits_history_long::delete_all_rows(void)
{
  reset_events_waits_history_long();
  return 0;
}

ha_rows
table_events_waits_history_long::get_row_count(void)
{
  return events_waits_history_long_size;
}