Recently our QuickBuild server went down by itself several times. We checked the server logs and found that there was a deadlock as follow which caused the memory spike. we set wrapper.java.maxmemory=4096, I think it should be fine. I attached the server log file for your references.

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 2020-12-17 10:17:22,470 [C3P0PooledConnectionPoolManager[identityToken->z8kfltaesj634k1iyllxx|58cae5cb)-AdminTaskTimer] WARN com.mchange.v2.async.ThreadPoolAsynchronousRunner - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@44547507 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
2020-12-17 10:20:56,673 [pool-1-thread-21150] ERROR com.pmease.quickbuild.grid.GridJob - Error notifying task node of job finishing (job class: 86efdbe6-673b-4b9b-8d92-373f930e71aa, job id: com.pmease.quickbuild.stepsupport.StepProcessJob, task node: QB_SERVER.com:8810)
    java.lang.OutOfMemoryError: Java heap space
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 Please look into the issue and advise.

 Thank you in advance,
ptrinh