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Xuefu Zhang commented on HIVE-17586: ------------------------------------ Actually no according java doc at https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ThreadPoolExecutor.html: {quote} If the pool currently has more than corePoolSize threads, excess threads will be terminated if they have been idle for more than the keepAliveTime (see getKeepAliveTime(java.util.concurrent.TimeUnit)). {quote} Because we use fixed pool size, there are no "excess threads" to idle out. > Make HS2 BackgroundOperationPool not fixed > ------------------------------------------ > > Key: HIVE-17586 > URL: https://issues.apache.org/jira/browse/HIVE-17586 > Project: Hive > Issue Type: Bug > Components: HiveServer2 > Affects Versions: 1.1.0 > Reporter: Xuefu Zhang > Assignee: Xuefu Zhang > Attachments: HIVE-17586.1.patch, HIVE-17586.patch > > > Currently the threadpool for background asynchronous operatons has a fixed > size controled by {{hive.server2.async.exec.threads}}. However, the thread > factory supplied for this threadpool is {{ThreadFactoryWithGarbageCleanup}} > which creates ThreadWithGarbageCleanup. Since this is a fixed threadpool, the > thread is actually never killed, defecting the purpose of garbage cleanup as > noted in the thread class name. On the other hand, since these threads never > go away, significant resources such as threadlocal variables (classloaders, > hiveconfs, etc) are holding up even if there is no operation running. This > can lead to escalated HS2 memory usage. > Ideally, the threadpool should not be fixed, allowing thread to die out so > resources can be reclaimed. The existing config > {{hive.server2.async.exec.threads}} is treated as the max, and we can add a > min for the threadpool {{hive.server2.async.exec.min.threads}}. Default value > for this configure is -1, which keeps the existing behavior. -- This message was sent by Atlassian JIRA (v6.4.14#64029)
