Synchrony no longer works after upgrade and 100% CPU usage

[Christoph Bratschi]

After upgrading from Confluence 6.4.1 to 6.7.1 the editor was no longer working and the server had permanently a very high CPU usage. Nothing could be found in the server logs.

After disabling Synchrony the system was running normal again. So this issue is related to Synchrony.

Settings in bin/setenv.sh:

CATALINA_OPTS="-Dsynchrony.port=8191 ${CATALINA_OPTS}"

Environment:

macOS, java 1.8.0

[Maksym Fedoryshyh]

Can you please attach thread dumps for Confluence and Synchrony, captured when high CPU is happening? Catching threads CPU utilisation would be very helpful as well (you can use htop or top -H to get that statistic)