Lokesh Jain created HDDS-2342:
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             Summary: ContainerStateMachine$chunkExecutor threads hold onto 
native memory
                 Key: HDDS-2342
                 URL: https://issues.apache.org/jira/browse/HDDS-2342
             Project: Hadoop Distributed Data Store
          Issue Type: Bug
          Components: Ozone Datanode
            Reporter: Lokesh Jain
            Assignee: Lokesh Jain


In a heap dump many threads in ContainerStateMachine$chunkExecutor holds onto 
native memory in the ThreadLocal map. Every such thread holds onto chunk worth 
of DirectByteBuffer. Since these threads are involved in write and read chunk 
operations, the JVM allocates chunk (16MB) worth of DirectByteBuffer in the 
ThreadLocalMap for every thread involved in IO. Also the native memory would 
not be GC'ed as long as the thread is alive.

It would be better to reduce the default number of chunk executor threads and 
have them in proportion to number of disks on the datanode.



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