This diagnostic alert warns you when the memory allocated to garbage collection, during a set monitoring period, exceeds a set threshold (as a percentage). If garbage collection consumes too much memory, it can affect the performance of the application. 

The following appears in the application log:

WARNING ; JVM ; JVM-1002 ; Garbage collection exceeded time limit ; not-detected ;  ;  ; {...}

This alert is enabled by default in Confluence 6.11 or later. 

To resolve this issue

There's no action required for this alert. However, this information may be helpful when investigating an outage or other performance issues.

What will happen if I ignore this alert? 

This alert is for information only. There's no direct action required, however, because long garbage collection (GC) pauses can cause the application to crash, you may want to improve your GC configuration. See Garbage Collection (GC) Tuning Guide

Can I change the threshold?

Yes, you can change the threshold and behaviour of this alert using the following system properties:

diagnostics.jvm.garbage.collector.percent

diagnostics.jvm.garbage.collector.monitoring.period.secs

diagnostics.jvm.memory.check.period.secs

See Configuring System Properties for more information on setting system properties.