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Comment by reidrac | Hacker News Reader

I haven't looked at the graphs, but they updated netty to 4.1.85.Final on 2022-11-10.

https://netty.io/news/2022/11/09/4-1-85-Final.html mentions that a potential memory leak was fixed. In includes a debug log warning of the leak; but enabling debug logging may be a no-no.

Perhaps could be worth reverting that and see if there's any change. Sounds cheap and harmless.

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Netty is a super complex and also super poorly documented project. I did weeks of exploration and found these JVM args:

      -Dio.netty.allocator.numDirectArenas=0
      -Dio.netty.noPreferDirect=true
      -Dio.netty.noUnsafe=true

work pretty well for us on any HTTP server. They slightly reduce performance as HTTP pool is weaker, but deceases memory usage by 25-40%, also eliminated one of a few memory leaks in an older version of KeyCloak.

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