In some situation, like suggested in some mysql optimization script, you may want to regularly run “FLUSH QUERY CACHE”.
First, open your terminal and try to run this command :
mysql -e 'FLUSH QUERY CACHE'
If there is no error, you can add that command in your cron job, such as this command to run it every 10 minutes :
*/10 * * * * mysql -e 'FLUSH QUERY CACHE'