Idle confluence opening hundreds of sockets

[Ken Poulton]

I have set up a staging server for Confluence Data Center.  It seems to work properly with a copy of the content from my production server.  But the staging server opens 20 sockets a minute and leaves them open.  This goes on until there are 800-1300 open sockets between the Catalina and Synchrony processes, and then the open socket count drops to near zero.  The cycle repeats every 40-65 minutes, with some variation.

The production server is on Confluence 7.19 on a RHEL8.10 VM and doesn't have these huge numbers of open sockets. The staging servers exhibit this problem on 8.5.15, 8.5.20 and 9.2.2, running on RHEL8.10 VMs.  The staging servers have only one logged-in (idle) user.

Safe Mode (apps off) does not change this.

Any ideas on what is causing this?

[Brant Schroeder]

@Ken Poulton is Confluence stock or have you installed some apps?  Could just be Java being Java and when you see it drop to near Zero the garbage collection just ran.  

[Ken Poulton]

I have 8 apps installed, but I get the same behavior with all the apps disabled in Safe Mode.

[Brant Schroeder]

@Ken Poulton if you run garbage collection do you get the same drop to almost zero?

[Ken Poulton]

Yes, a manual garbage collect drives the socket count back to near zero.

But according to logs/gc*log, the garbage collects are only occurring a few times day, not enough to account for the sockets getting reset every hour or so.