MySQL slow query log file time elapse
This is probably done by your log rotation software. On my Ubuntu machine its defined in /etc/logrotate.d/mysql-server.

logrotate is run daily by a cron job. Take a look in /etc/crontab. In my case I have the following:


25 6    * * *   root    test -x /usr/sbin/anacron || ( cd / &amp;&amp; run-parts --report /etc/cron.daily )


So daily jobs get run at 6:25AM.

I also have a file /etc/cron.daily/logrotate which configures log rotate as a daily job.

Most Linux installations would have something similar. If you're running on Windows I'm afraid I have no idea.