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Hudson commented on ZOOKEEPER-3399: ----------------------------------- SUCCESS: Integrated in Jenkins build ZooKeeper-trunk #538 (See [https://builds.apache.org/job/ZooKeeper-trunk/538/]) ZOOKEEPER-3399: Remove logging in getGlobalOutstandingLimit for optimal (eolivelli: rev 968f5f365e53d0bcbbe0225cc382327badbd8380) * (edit) zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/LeaderZooKeeperServer.java * (edit) zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/FollowerZooKeeperServer.java > Remove logging in getGlobalOutstandingLimit for optimal performance. > -------------------------------------------------------------------- > > Key: ZOOKEEPER-3399 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-3399 > Project: ZooKeeper > Issue Type: Bug > Components: server > Affects Versions: 3.6.0 > Reporter: Michael Han > Assignee: Michael Han > Priority: Major > Labels: pull-request-available > Fix For: 3.6.0 > > Time Spent: 1h > Remaining Estimate: 0h > > Recently we have moved some of our production clusters to the top of the > trunk. One issue we found is a performance regression on read and write > latency on the clusters where the quorum is also serving traffic. The average > read latency increased by 50x, p99 read latency increased by 300x. > The root cause is a log statement introduced in ZOOKEEPER-3177 (PR711), where > we added a LOG.info statement in getGlobalOutstandingLimit. > getGlobalOutstandingLimit is on the critical code path for request processing > and for each request, it will be called twice (one at processing the packet, > one at finalizing the request response). This not only degrades performance > of the server, but also bloated the log file, when the QPS of a server is > high. > This only impacts clusters when the quorum (leader + follower) is serving > traffic. For clusters where only observers are serving traffic no impact is > observed. > > -- This message was sent by Atlassian JIRA (v7.6.3#76005)