Slow query logging

Slow query logging

You may need to test and review slow queries on a database. By default slow queries are not logged.

To enable slow query logging, add 'logslow' => 1  to the dboptions array in config.php. This will cause queries over one second (the '1' can be changed to any number of seconds) to be logged in the 'log_queries' table in the database.

$CFG->dboptions = array ( 'dbpersist' => 0, 'dbport' => '', 'dbsocket' => '', 'logslow' => 1 ;

The log_queries table can be exported and sent to Totara Support.

Most database administrations tools (such as MySQL Workbench, PHPMyAdmin, etc.) have a graphical user interface for this. You can also do this from the command line on the server.

  • MySQL

  • PostgreSQL

  • MSSQL

Only enable slow query logging long enough to test slow queries and immediately disable after testing.