----
Private #upstream issue: https://bugs.chromium.org/p/gerrit/issues/detail?id=13858
----
On September 16 2020, our Gerrit primary instance on gerrit1001 went unresponsive and had to be restarted:
```
[production]
09:22 <jynus> restarting gerrit service on gerrit1001, unresponsive
```
A quick glance at logs show:
```
[2020-09-16 08:59:26,287] [HTTP-964160] INFO org.eclipse.jetty.io.ManagedSelector : Caught select() failure, trying to recover: java.lang.OutOfMemoryError: Java heap space
[2020-09-16 08:59:26,288] [HTTP-964151] INFO org.eclipse.jetty.io.ManagedSelector : Caught select() failure, trying to recover: java.lang.OutOfMemoryError: Java heap space
```
Heap objects can be seen via JavaMelody: https://gerrit.wikimedia.org/r/monitoring?part=heaphisto and click {nav details} in the lower corner. Or using `jmap -histo`.
Memory usage can be seen at https://gerrit.wikimedia.org/r/monitoring?part=graph&graph=usedMemory
Java memory usage over one year:
{F32352401 size=full}
{P12604 lines=25}