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Amruth Sampath commented on HIVE-22165: --------------------------------------- Hi [~gopalv], [~rajesh.balamohan]!, Kindly let me know if I have to do anything more to get this in. Your help is much appreciated. Thanks in advance! > Synchronisation introduced by HIVE-14296 on SessionManager.closeSession > causes high latency in a busy hive server > ----------------------------------------------------------------------------------------------------------------- > > Key: HIVE-22165 > URL: https://issues.apache.org/jira/browse/HIVE-22165 > Project: Hive > Issue Type: Bug > Components: HiveServer2 > Affects Versions: 2.1.0, 2.3.2 > Reporter: Amruth Sampath > Assignee: Amruth Sampath > Priority: Major > Attachments: HIVE-22165.patch, HIVE-22165.patch.1 > > > HIVE-14296 introduces this > [commit|https://github.com/apache/hive/commit/477a47d3b4b9e3da3c22465217c2024588f7f000] > which adds synchronization to SessionManager.closeSession. > And it looks like it is used only for logging purposes. > In a busy hive server where 5-10 sessions are created closed every second, an > increase in latency of any other downstream services (Zk, HDFS) causes a > queueing effect (lot of threads getting blocked on > SessionManager.closeSession) creating an induced latency of 3-5 minutes at > times for just closing the session. > Since the gauge (MetricsConstant.HS2_OPEN_SESSIONS) is already tracking the > open session counts, the synchronization (along with the additional logging) > can be removed without any functionality losses. -- This message was sent by Atlassian Jira (v8.3.4#803005)