#
# Copyright (c) 2011, 2020 Oracle and/or its affiliates.  All rights reserved.
#
# See the file LICENSE for license information.
#
# dist/events.in - This description of Oracle Berkeley DB's internal
# events hierarchy is processed by 'dist/s_include' to generate the
# platform-independant file dist/db_provider.d. The 'configure' step on the
# target operating system generate platform-specific include file.
#
#	s_include	->	dist/db_provider.d
#	configure	->	<build_directory>/db_provider.h
#
# There are two kinds of entries in events.in, describing either an event class
# or an individual event. The entries starting in the first column are class
# names, consisting of a single word. The class's individual events follow,
# described as if they were an ANSI C function signature;
#
# Events are listed grouped by their relation to one another, rather than
# alphabetically. For instance allocation and free events are adjacent.
# New, unrelated events are placed at the end of their event class.
#

# The alloc class covers the allocation of "on disk" database pages.
alloc
    # An attempt to allocate a database page of type 'type' for database 'db'
    # returned 'ret'. If the allocation succeeded then ret is 0, pgno is the
    # location of the new page, and pg is the address of the new page.
    # Details of the page can be extracted from the pg pointer.
    new(char *file, char *db, unsigned pgno, unsigned type,
    	struct _db_page *pg, int ret);
    # An attempt to free the page 'pgno' of 'db' returned 'ret'.
    # When successful the page is returned to the free list
    # or the file is truncated.
    free(char *file, char *db, unsigned pgno, unsigned ret);
    # A btree split of pgno in db is being attempted. The parent page number
    # and the level in the btree are also provided.
    btree_split(char *file, char *db, unsigned pgno, unsigned parent,
    	unsigned level);

# These DB API calls provide the name of the file and database being accessed.
# In-memory databases will have a NULL (0) file name address. The db name will
# be null unless subdatabases are in use.
db
    # The database or file name was opened. The 20 byte unique fileid can be
    # used to keep track of databases as they are created and destroyed.
    open(char *file, char *db, unsigned flags, uint8_t *fileid);
    # The database or file name was closed.
    close(char *file, char *db, unsigned flags, uint8_t *fileid);
    # An attempt is being made to open a cursor on the database or file.
    cursor(char *file, char *db, unsigned txnid, unsigned flags,
    	uint8_t *fileid);
    # An attempt is being made to get data from a db.
    get(char *file, char *db, unsigned txnid, DBT *key, DBT *data,
    	unsigned flags);
    # An attempt is being made to put data to a db.
    put(char *file, char *db, unsigned txnid, DBT *key, DBT *data,
    	unsigned flags);
    # An attempt is being made to delete data from a db.
    del(char *file, char *db, unsigned txnid, DBT *key, unsigned flags);

# The lock class monitors the transactional consistency locks: page, record,
# and database. It also monitors the non-transactional file handle locks.
lock
    # The thread is about to suspend itself because another locker already has
    # a conflicting lock on object 'lock'.  The lock DBT's data points to
    # a __db_ilock structure, except for the atypical program which uses
    # application specific locking.
    suspend(DBT *lock, db_lockmode_t lock_mode);
    # The thread is awakening from a suspend.
    resume(DBT *lock, db_lockmode_t lock_mode);
    # The lock is being freed.
    put(struct __sh_dbt *lock, unsigned flags);
    # The lock would have been freed except that its refcount was greater
    # than 1.
    put_reduce_count(struct __sh_dbt *lock, unsigned flags);

    # These lock counters are included by --enable-perfmon-statistics.

    # The locker_id's lock request in lock_obj is about to be aborted in
    # order to resolve a deadlock. The lock region's st_ndeadlocks has
    # been incremented.
    deadlock(unsigned st_ndeadlocks, unsigned locker_id,
        struct __sh_dbt *lock_obj);
    # A DB_LOCK_NOWAIT lock request by locker_id would have had to wait.
    # The lock regions's st_lock_nowait has been incremented and
    # the request returns DB_LOCK_NOTGRANTED.
    nowait_notgranted(unsigned count, DBT *lock, unsigned locker_id);
    request(unsigned request_count, DBT *lock, unsigned locker_id);
    upgrade(unsigned upgrade_count, DBT *lock, unsigned locker_id);
    # A lock is being stolen from one partition for another one
    # The 'from' lock partition's st_locksteals has been incremented.
    steal(unsigned st_locksteals, unsigned from, unsigned to);
    # A lock object is being stolen from one partition for another one.
    # The 'from' lock partition's st_objectsteals has been incremented.
    object_steal(unsigned st_objectsteals, unsigned from, unsigned to);
    # A lock wait expired due to the lock request timeout.
    locktimeout(unsigned st_nlocktimeouts, const DBT *lock);
    # A lock wait expired due to the transaction's timeout.
    txntimeout(unsigned st_ntxntimeouts, const DBT *lock);
    # The allocation or deallocation of the locker id changed the number
    # of active locker identifiers.
    nlockers(unsigned active, unsigned locker_id);
    # The allocation of the locker id set a new maximum
    # number of active locker identifiers.
    maxnlockers(unsigned new_max_active, unsigned locker_id);

# Log - Transaction log 
log
    read(unsigned read_count, unsigned logfile);

# The mpool class monitors the allocation and management of memory,
# including the cache.
mpool
    # Read a page from file into buf.
    read(char *file, unsigned pgno, struct __bh *buf);
    # Write a page from buf to file.
    write(char *file, unsigned pgno, struct __bh *buf);
    # This is an attempt to allocate size bytes from region_id.
    # The reg_type is one of the reg_type_t enum values.
    env_alloc(unsigned size, unsigned region_id, unsigned reg_type);
    # The page is about to be removed from the cache.
    evict(char *file, unsigned pgno, struct __bh *buf);
    # The memory allocator has incremented wrap_count after searching through
    # the entire region without being able to fulfill the request for
    # alloc_len bytes. As wrap_count increases the library makes more effort
    # to allocate space.
    alloc_wrap(unsigned alloc_len, int region_id, int wrap_count,
    	int put_counter);

    # These mpool counters are included by --enable-perfmon-statistics.

    # The eviction of a clean page from a cache incremented st_ro_evict.
    clean_eviction(unsigned st_ro_evict, unsigned region_id);
    # The eviction of a dirty page from a cache incremented st_rw_evict.
    # The page has already been written out.
    dirty_eviction(unsigned st_rw_evict, unsigned region_id);
    # An attempt to allocate memory from region_id failed.
    fail(unsigned failure_count, unsigned alloc_len, unsigned region_id);
    free(unsigned freed_count, unsigned alloc_len, unsigned region_id);
    longest_search(unsigned count, unsigned alloc_len, unsigned region_id);
    free_frozen(unsigned count, char *file, unsigned pgno);
    freeze(unsigned hash_frozen, unsigned pgno);
    # A search for pgno of file incremented st_hash_searches.
    hash_search(unsigned st_hash_searches, char *file, unsigned pgno);
    # A search for pgno of file increased st_hash_examined by the number
    # of hash buckets examined.
    hash_examined(unsigned st_hash_examined, char *file, unsigned pgno);
    # A search for pgno of file set a new maximum st_hash_longest value.
    hash_longest(unsigned st_hash_longest, char *file, unsigned pgno);
    # A file's st_map count was incremented after a page was mapped into
    # memory.  The mapping might have caused disk I/O.
    map(unsigned st_map, char *file, unsigned pgno);
    # The hit count was incremented because pgno from file was found
    # in the cache.
    hit(unsigned st_cache_hit, char *file, unsigned pgno);
    # The miss count was incremented because pgno from file was
    # not already present in the cache.
    miss(unsigned st_cache_miss, char *file, unsigned pgno);
    # The st_page_create field was incremented because
    # the pgno of file was created in the cache.
    page_create(unsigned st_page_create, char *file, unsigned pgno);
    # The st_page_in field was incremented because
    # the pgno from file was read into the cache.
    page_in(unsigned st_page_in, char *file, unsigned pgno);
    # The st_page_out field was incremented because
    # the pgno from file was written out.
    page_out(unsigned st_page_out, char *file, unsigned pgno);
    thaw(unsigned count, char *file, unsigned pgno);
    alloc(unsigned success_count, unsigned len, unsigned region_id);
    nallocs(unsigned st_alloc, unsigned alloc_len);
    alloc_buckets(unsigned st_alloc_buckets, unsigned region_id);
    alloc_max_buckets(unsigned max, unsigned region_id);
    alloc_max_pages(unsigned max, unsigned region_id);
    alloc_pages(unsigned count, unsigned region_id);

    backup_spins(unsigned spins, char *file, unsigned pgno);`

    # The aggressiveness of a buffer cache allocation increases as more
    # involved methods are needed in order to free up the requested space
    # in the cache with the indicated region_id.
    # aggressive: the agressiveness of an allocation request was increased.
    # max_aggressive: the agressiveness of an allocation request was increased
    # to a new maximum.
    aggressive(unsigned st_alloc_aggressive, unsigned region_id);
    max_aggressive(unsigned st_alloc_max_aggr, unsigned region_id);

# The mutex category monitors includes shared latches.  The alloc_id value
# is one of the MTX_XXX definitions from dbinc/mutex.h
mutex
    # This thread is about to suspend itself because a thread has the
    # mutex or shared latch locked in a mode which conflicts with the
    # this request.
    suspend(unsigned mutex, unsigned excl, unsigned alloc_id,
    	struct __db_mutex_t *mutexp);
    # The thread is returning from a suspend and will attempt to obtain
    # the mutex or shared latch again. It might need to suspend again.
    resume(unsigned mutex, unsigned excl, unsigned alloc_id,
    	struct __db_mutex_t *mutexp);

    # These mutex counters are included by --enable-perfmon-statistics.

    # Increment the count of times that the mutex was free when trying
    # to lock it.
    set_nowait(unsigned mutex_set_nowait, unsigned mutex);
    # Increment the count of times that the mutex was busy when trying
    # to lock it.
    set_wait(unsigned mutex_set_wait, unsigned mutex);
    # Increment the count of times that the shared latch was free
    # when trying to get a shared lock on it.
    set_rd_nowait(unsigned mutex_set_rd_nowait, unsigned mutex);
    # Increment the count of times that the shared latch was already
    # exclusively latched when trying to get a shared lock on it.
    set_rd_wait(unsigned mutex_set_rd_wait, unsigned mutex);
    # Increment the count of times that a hybrid mutex had to block
    # on its condition variable.  n a busy system this might happen
    # several times before the corresponding hybrid_wakeup.
    hybrid_wait(unsigned hybrid_wait, unsigned mutex);
    # Increment the count of times that a hybrid mutex finished
    # one or more waits for its condition variable.
    hybrid_wakeup(unsigned hybrid_wakeup, unsigned mutex);

# The race events are triggered when the interactions between two threads
# causes a rarely executed code path to be taken. They are used primarily
# to help test and diagnose race conditions, though if they are being
# triggered too frequently it could result in performance degradation.
# They are intended for use by Berkeley DB engineers.
race
    # A Btree search needs to wait for a page lock and retry from the top.
    bam_search(char *file, char *db, int errcode, struct _db_page *pg,
    	struct _db_page *parent, unsigned flags);
    # A record was not found searching an off-page duplicate tree.
    # Retry the search.
    dbc_get(char *file, char *db, int errcode, unsigned flags, DBT *key);
    # The thread could not immediately open and lock the file handle
    # without waiting. The thread will close, wait, and retry.
    fop_file_setup(char *file, int errcode, unsigned flags);
    # A get next or previous in a recno db had to retry.
    ramc_get(char *file, char *db, struct _db_page *pg, unsigned flags);

# The statistics counters for replication are for internal use.
rep
    election(unsigned count, unsigned generation);
    election_won(unsigned count, unsigned generation);
    ext_chunk_rereq(unsigned rereq, unsigned master_id);
    ext_deleted(unsigned deleted, unsigned eid);
    ext_duplicated(unsigned duplicated, unsigned eid);
    ext_records(unsigned records, unsigned eid);
    ext_truncated(unsigned truncated, unsigned eid);
    ext_update_rereq(unsigned update_rereq, unsigned eid);
    log_queued(unsigned count, DB_LSN *lsn);
    log_request(unsigned count, unsigned eid);
    master_change(unsigned count, unsigned eid);
    pg_duplicated(unsigned eid, unsigned pgno, unsigned file, unsigned count);
    pg_record(unsigned count, unsigned eid);
    pg_request(unsigned count, unsigned eid);

# The txn category covers the basic transaction operations.
txn
    # A transaction was successfully begun.
    begin(unsigned txnid, unsigned flags);
    # A transaction is starting to commit.
    commit(unsigned txnid, unsigned flags);
    # The transaction is starting to prepare, flushing the log
    # so that a future commit can be guaranteed to succeed.
    # The global identifier field is 128 bytes long.
    prepare(unsigned txnid, uint8_t *gid);
    # The transaction is about to abort.
    abort(unsigned txnid);

    # These txn counters are included by --enable-perfmon-statistics.

    # Beginning the transaction incremented st_nbegins.
    nbegins(unsigned st_nbegins, unsigned txnid);
    # Aborting the transaction incremented st_naborts.
    naborts(unsigned st_naborts, unsigned txnid);
    # Committing the transaction incremented st_ncommits.
    ncommits(unsigned st_ncommits, unsigned txnid);
    # Beginning or ending the transaction updated the number of active
    # transactions.
    nactive(unsigned st_nactive, unsigned txnid);
    # The creation of the transaction set a new maximum number
    # of active transactions.
    maxnactive(unsigned st_maxnactive, unsigned txnid);
    nsnapshot(unsigned st_nsnapshot, unsigned txnid);
    maxnsnapshot(unsigned st_maxnsnapshot, unsigned txnid);