Enabling InnoDB Monitors •The  InnoDB  Lock Monitor prints additional lock information as part of the standard  InnoDB  Monitor output. •Row operation data •Buffer pool statistics •Redo log data •Insert buffer and adaptive hash index statistics •Pending I/O operations and related statistics •Table and record locks held by active transactions 3340 Enable the standard  InnoDB  Monitor by setting the  innodb_status_output  system variable to  ON . The  PROCESS  privilege is required to enable or disable  InnoDB  Monitors. The  innodb_status_output  and  innodb_status_output_locks  system variables are used to enable the standard  InnoDB  Monitor and  InnoDB  Lock Monitor. The header for the standard  InnoDB  Monitor ( INNODB MONITOR OUTPUT ) is also used for the Lock Monitor because the latter produces the same output with the addition of extra lock information. InnoDB  monitor output begins with a header containing a timestamp and the monitor name. For example: To assist with troubleshooting,  InnoDB  temporarily enables standard  InnoDB Monitor output under certain conditions. For more information, see Section 15.21, “InnoDB Troubleshooting” . InnoDB  monitors should only be enabled when you actually want to see monitor information because output generation causes some performance decrement. Also, if monitor output is directed to the error log, the log may become quite large if you forget to disable the monitor later. On Unix and Unix-like systems,  stderr  is typically directed to the terminal unless configured otherwise. For more information, see Default Error Log Destination on Unix and Unix-Like Systems. On Windows,  stderr  is directed to the default log file unless configured otherwise. If you want to direct the output to the console window rather than to the error log, start the server from a command prompt in a console window with the  --console  option. For more information, see Default Error Log Destination on Windows. InnoDB  sends the monitor output to  stderr  rather than to  stdout  or fixed-size memory buffers to avoid potential buffer overflows. When  InnoDB  monitors are enabled for periodic output,  InnoDB  writes the output to  mysqld  server standard error output ( stderr ) every 15 seconds, approximately. 15.17.2 Enabling InnoDB Monitors Note Enabling the Standard InnoDB Monitor ===================================== 2014-10-16 18:37:29 0x7fc2a95c1700 INNODB MONITOR OUTPUT =====================================