Zammad stops fetching E-Mails || Zammad scheduler not working correctly

[Fernien]

Infos

• Docker version: 26.0.0, build 2ae903e
• Docker-compose version: v2.25.0
• Operating system (Docker host): Debian GNU/Linux 12 (bookworm)

Expected behavior

• Always keeps fetching and downloading new E-Mails
• Clean health check in Monitoring Tab

Actual behavior

*Zammad stops fetching new E-Mails almost every day
*Monitoring Tab never clean. Cannot get rid of "scheduler may not run (last execution of CacheClearJob.perform_now 9 days ago) - please contact your system administrator". "Channel: Email::Account in is active but not fetched for about XX hours" coming daily

All i can find are these log entries but i have no idea how to fix them or what the exact problem is

zammad-scheduler-1 | E, [2024-04-03T07:02:12.611619#1-340820] ERROR -- : Can't reconnect to database #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use>
zammad-scheduler-1 | E, [2024-04-03T07:02:13.611186#1-340800] ERROR -- : execute DataPrivacyTaskJob.perform_now (try_count 7) exited with error #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use> in: 5.000230764 seconds.
zammad-scheduler-1 | E, [2024-04-03T07:02:17.595606#1-328740] ERROR -- : execute Sessions.jobs (try_count 10) exited with error #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use> in: 5.000245081 seconds.
zammad-scheduler-1 | E, [2024-04-03T07:02:17.625294#1-352840] ERROR -- : execute Ticket.process_pending (try_count 4) exited with error #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use> in: 5.000236675 seconds.
zammad-scheduler-1 | E, [2024-04-03T07:02:18.601090#1-334760] ERROR -- : execute Ticket.process_auto_unassign (try_count 9) exited with error #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use> in: 5.000257424 seconds.
zammad-scheduler-1 | E, [2024-04-03T07:02:18.611410#1-340800] ERROR -- : Can't reconnect to database #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use>
zammad-scheduler-1 | E, [2024-04-03T07:02:18.626268#1-352860] ERROR -- : execute Stats.generate (try_count 4) exited with error #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use> in: 5.00024512 seconds.
zammad-scheduler-1 | E, [2024-04-03T07:02:19.601629#1-334780] ERROR -- : execute ExternalCredential::Exchange.refresh_token (try_count 9) exited with error #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use> in: 5.000267743 seconds.
zammad-scheduler-1 | E, [2024-04-03T07:02:19.626952#1-352880] ERROR -- : execute Chat.cleanup_close (try_count 4) exited with error #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use> in: 5.000269346 seconds.
zammad-scheduler-1 | E, [2024-04-03T07:02:22.595865#1-328740] ERROR -- : Can't reconnect to database #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use>
zammad-scheduler-1 | E, [2024-04-03T07:02:22.596004#1-328740] ERROR -- : Failed to run Sessions.jobs after 11 tries.
zammad-scheduler-1 | E, [2024-04-03T07:02:22.625502#1-352840] ERROR -- : Can't reconnect to database #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use>
zammad-scheduler-1 | E, [2024-04-03T07:02:23.601358#1-334760] ERROR -- : Can't reconnect to database #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use>
zammad-scheduler-1 | E, [2024-04-03T07:02:23.626536#1-352860] ERROR -- : Can't reconnect to database #<ActiveRecord::ConnectionTimeoutError: could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use>

Steps to reproduce the behavior

I'm not completely sure how to reproduce it since the fetching just stops working seemingly randomly. The log errors are after a fresh installation

I added vm.max_map_count=262144 to sysctl.conf. I have the same problem on 2 different host systems with 2 different zammad installations. Zammad Version 6.4.x

[mgruner]

@Fernien thanks for your report. If you want to use Zammad 6.4.x, you need to include the changes from #402 in your deployment. Specifically the POSTGRESQL_OPTIONS with the explicit setting of the database pool size. Please let us know if it works for you.

I'm closing this issue as it is not about a supported Zammad version.

[Fernien]

@Fernien thanks for your report. If you want to use Zammad 6.4.x, you need to include the changes from #402 in your deployment. Specifically the POSTGRESQL_OPTIONS with the explicit setting of the database pool size. Please let us know if it works for you.

I'm closing this issue as it is not about a supported Zammad version.

It seems to have solved the prolems. Thanks for the quick help and sorry for the inconvenience