How to Access MySQL Error Logs

Oftentimes, the root cause of slowdowns, crashes, or other unexpected behavior in MySQL can be determined by analyzing its error logs. On Ubuntu systems, the default location for the MySQL is /var/log/mysql/error.log. In many cases, the error logs are most easily read with the less program, a command line utility that allows you to view files but not edit them:

sudo less /var/log/mysql/error.log

If MySQL isn’t behaving as expected, you can obtain more information about the source of the trouble by running this command and diagnosing the error based on the log’s contents.