I'm running Windows 2012r2 on a new server, with Plesk 12.5 and MySQL 5.6 installed.

There's a backup script which takes a DB dump and zips website data files that runs each day. However, it brings the server to a crawl while it runs - but more confusingly even after it has finished.

There are lots of cgi-php.exe processes (for PHP 7 and 5.6 under IIS) that shoot up to consume almost all of the CPU load, and they'll stay there until I restart MySQL... That's what I find so confusing. The MySQL CPU load is very low, but it fixes the php problem when restarting.

How can I begin to troubleshoot this problem? Is there something related to MySQL that could cause a backlog with PHP?


From your question it looks like PHP process gets hung during the interaction with MySQL. I would suggest enabling slow queries and trace the time taking queries.

  • Thanks, I've enabled the slow query log in MySQL, but the only transaction is the HUGE mysqldump query that takes place, which causes the problem. I could understand it if PHP was slow during the backups, but improved afterwards - but it's slow after too. The backup size (30GB) exceeds the innodb buffer pool size (20GB), so I thought it may have something to do with removing old data from the buffer after the backup? – IanCun Apr 24 '16 at 14:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.