BUG#57275 binlog_cache_size affects trx- and stmt-cache and gets twice the expected memory

      
After the WL#2687, the binlog_cache_size and max_binlog_cache_size affect both the
stmt-cache and the trx-cache. This means that the resource used is twice the amount
expected/defined by the user.
      
The binlog_cache_use is incremented when the stmt-cache or the trx-cache is used
and binlog_cache_disk_use is incremented when the disk space from the stmt-cache or the
trx-cache is used. This behavior does not allow to distinguish which cache may be harming
performance due to the extra disk accesses and needs to have its in-memory cache
increased.
      
To fix the problem, we introduced two new options and status variables related to the
stmt-cache:
      
  Options:
      
    . binlog_stmt_cache_size
    . max_binlog_stmt_cache_size
      
    Status Variables:
      
    . binlog_stmt_cache_use
    . binlog_stmt_cache_disk_use

So there are

  . binlog_cache_size that defines the size of the transactional cache for
  updates to transactional engines for the binary log.

  . binlog_stmt_cache_size that defines the size of the statement cache for
  updates to non-transactional engines for the binary log.

  . max_binlog_cache_size that sets the total size of the transactional
  cache.

  . max_binlog_stmt_cache_size that sets the total size of the statement
  cache.

  . binlog_cache_use that identifies the number of transactions that used the
  temporary transactional binary log cache.

  . binlog_cache_disk_use that identifies the number of transactions that used
  the temporary transactional binary log cache but that exceeded the value of
  binlog_cache_size.

  . binlog_stmt_cache_use that identifies the number of statements that used the
  temporary non-transactional binary log cache.

  . binlog_stmt_cache_disk_use that identifies the number of statements that used
  the temporary non-transactional binary log cache but that exceeded the value of
  binlog_stmt_cache_size.

1 files changed, 4 insertions, 2 deletions

diff --git a/sql/mysqld.h b/sql/mysqld.h
index 6e81c240f7d..4988248e936 100644
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -152,6 +152,7 @@ extern ulonglong keybuff_size;
 extern ulonglong thd_startup_options;
 extern ulong thread_id;
 extern ulong binlog_cache_use, binlog_cache_disk_use;
+extern ulong binlog_stmt_cache_use, binlog_stmt_cache_disk_use;
 extern ulong aborted_threads,aborted_connects;
 extern ulong delayed_insert_timeout;
 extern ulong delayed_insert_limit, delayed_queue_size;
@@ -171,8 +172,9 @@ extern uint  slave_net_timeout;
 extern uint max_user_connections;
 extern ulong what_to_log,flush_time;
 extern ulong max_prepared_stmt_count, prepared_stmt_count;
-extern ulong binlog_cache_size, open_files_limit;
-extern ulonglong max_binlog_cache_size;
+extern ulong open_files_limit;
+extern ulong binlog_cache_size, binlog_stmt_cache_size;
+extern ulonglong max_binlog_cache_size, max_binlog_stmt_cache_size;
 extern ulong max_binlog_size, max_relay_log_size;
 extern ulong opt_binlog_rows_event_max_size;
 extern ulong rpl_recovery_rank, thread_cache_size;