MySQL Logging and LogRotation

25 Oct 2007 logging documentation

On Debian based systems, MySQL logging (and logrotation) is setup automatically so I’ve never had to worry about it. Unfortunately, I’m not using Debian at the moment.

The options used to start MySQL can be gleaned from ps ax | grep mysql ; in particular this will show the –datadir setting, which is where logs are created by default.

Troubleshooting Logs

  • –log – the general query log – when clients connect and disconnect and all sql statements. By default, created with a name of host_name.log
  • ** –log-error** – diagnostic messages about startup and shutdown and abnormal conditions. By default, created with a name of host_name.err. If mysqld is invoked directly errors will be written to stderr; if mysqld is started by way of the mysqld_safe script (directly or via init.d) error logging may go to syslog (and therefore usually to /var/log)
  • –log-slow-queries – log queries that take longer than the long_query_time server variable (10s by default) to run. By default, created with a name of host_name-slow.log

Replication/Binary Logs




comments powered by Disqus

  « Previous: Next: »