There are many variables in MariaDB that you can use to define what to log and when to log.

This article will give you an overview of the different logs and how to enable/disable logging to these.

Note that storage engines can have their logs too: for example, InnoDB keeps an Undo Log and a Redo Log which are used for rollback and crash recovery. However, this page only lists MariaDB server logs.

The error log

  • Always enabled
  • Usually a file in the data directory, but some distributions may move this to other locations.
  • All critical errors are logged here.
  • One can get warnings to be logged by setting log_warnings.
  • With the mysqld_safe --syslog option one can duplicate the messages to the system's syslog.

General query log

  • Enabled with --general-log
  • Logs all queries to a file or table.
  • Useful for debugging or auditing queries.
  • The super user can disable logging to it for a connection by setting SQL_LOG_OFF to 1.

Slow Query log

The binary log

Examples

If you know that your next query will be slow and you don't want to log it in the slow query log, do:

SET LOCAL SLOW_QUERY_LOG=0;

If you are a super user running a log batch job that you don't want to have logged (for example mysqldump), do:

SET LOCAL SQL_LOG_OFF=1, LOCAL SLOW_QUERY_LOG=0;

mysqldump in MariaDB 10.1 will do this automatically if you run it with the --disable-log-querys

See also

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