/
.How to log slow queries v1

.How to log slow queries v1

How can I enable slow query logging?

Problem

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

Solution

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.

Example
$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.