Xwiki 10.1 stops responding, uses 99% CPU

Help / Discuss
1

Hi, on Ubuntu 16.04, xwiki 10.0 and 10.1 packages, I am seeing new behavior. Twice in the past week, the wiki has stopped responding and is consuming 99% CPU on the host machine. Previously, I updated to xwiki 10.1 and rebooted; this time, rebooting or restarting tomcat8 does not seem to help.

I have also recently installed the File Manager extension, that is the only other significant change during this period.

I am not sure how to debug this problem. Any assistance would be welcome.

$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.4 LTS"

$ dpkg --get-selections | grep xwiki
xwiki-common					install
xwiki-mysql-common				install
xwiki-tomcat8-common				install
xwiki-tomcat8-mysql				install
2

Quick update: weirdly, it is running again and using a normal amount of CPU. I rebooted and left it running for some time (>10mins) before this miracle happened. Any clue what it is doing when it flips out and maxes CPU like that?

3

The first thing to do usually is to take a thread dump of the JVM to see what’s running exactly.

4

Thanks! I’ll figure out how to do that and wait for a future opportunity.