Tomcat JIRA at 100% - blocked thread "MySQL Cancellation Timer"

java process is using all available CPU cores, and I have taken a number of thread dumps at 15 sec intervals.

The thread dumps repeatedly show 1 blocked thread "MySQL Cancellation Timer"

Any ideas what is causing this and what i can do to fix/prevent?

We are running JIRA 6.3.7



1 answer

0 vote
Chris Fuller Atlassian Team Oct 22, 2014

A "BLOCKED" thread is one that has suspended execution as it waits for some other thread to release an object monitor.  It is, by definition, not using the CPU.  You should instead be looking for threads that are in the "RUNNING" state.

100% CPU is more likely to be caused by GC thrashing than anything else.  Turning on GC logging may help you confirm this (multiple "Full GC" reports back-to-back usually indicate a problem, here).  An example of what might cause this is something trying to read all of the JIRA issues into memory or something similarly evil.

There really isn't enough information here to help any further with this, but our support team can usually help with tracking down the culprit when something like this is happening.

Suggest an answer

Log in or Sign up to answer
Atlassian Community Anniversary

Happy Anniversary, Atlassian Community!

This community is celebrating its one-year anniversary and Atlassian co-founder Mike Cannon-Brookes has all the feels.

Read more
Community showcase
Julia Dillon
Posted Tuesday in Jira

Tell us how your team runs on Jira!

Hey Atlassian Community! Today we are launching a bunch of customer stories about the amazing work teams, like Dropbox and Twilio, are doing with Jira. You can check out the stories here. The thi...

302 views 1 18
Join discussion

Atlassian User Groups

Connect with like-minded Atlassian users at free events near you!

Find a group

Connect with like-minded Atlassian users at free events near you!

Find my local user group

Unfortunately there are no AUG chapters near you at the moment.

Start an AUG

You're one step closer to meeting fellow Atlassian users at your local meet up. Learn more about AUGs

Groups near you