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https://issues.apache.org/jira/browse/ZOOKEEPER-2684?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15860158#comment-15860158
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Alexander Shraer commented on ZOOKEEPER-2684:
---------------------------------------------
If I understand the concern correctly, you're worried that we'd consider a
duplicate request as legitimate because it has op cxid < queued cxid like in
the session migration case. I agree that if something goes wrong that's
possible. But, I think we should just log this when it happens, maybe Log.warn.
This is very similar
to what is done in other parts of ZooKeeper, see for example Follower.java
when the follower gets a proposal which it doesn't expect.
It is also somewhat related to ZooKeeper-22 Jira, which is about identifying
whether a client's operation has been executed or not. I don't think we want to
tackle it here.
> Fix a crashing bug in the mixed workloads commit processor
> ----------------------------------------------------------
>
> Key: ZOOKEEPER-2684
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2684
> Project: ZooKeeper
> Issue Type: Bug
> Components: server
> Affects Versions: 3.6.0
> Environment: with pretty heavy load on a real cluster
> Reporter: Ryan Zhang
> Assignee: Ryan Zhang
> Priority: Blocker
> Attachments: ZOOKEEPER-2684.patch
>
>
> We deployed our build with ZOOKEEPER-2024 and it quickly started to crash
> with the following error
> atla-buh-05-sr1.prod.twttr.net: 2017-01-18 22:24:42,305 - ERROR
> [CommitProcessor:2]
> -org.apache.zookeeper.server.quorum.CommitProcessor.run(CommitProcessor.java:268)
> – Got cxid 0x119fa expected 0x11fc5 for client session id 1009079ba470055
> atla-buh-05-sr1.prod.twttr.net: 2017-01-18 22:32:04,746 - ERROR
> [CommitProcessor:2]
> -org.apache.zookeeper.server.quorum.CommitProcessor.run(CommitProcessor.java:268)
> – Got cxid 0x698 expected 0x928 for client session id 4002eeb3fd0009d
> atla-buh-05-sr1.prod.twttr.net: 2017-01-18 22:34:46,648 - ERROR
> [CommitProcessor:2]
> -org.apache.zookeeper.server.quorum.CommitProcessor.run(CommitProcessor.java:268)
> – Got cxid 0x8904 expected 0x8f34 for client session id 51b8905c90251
> atla-buh-05-sr1.prod.twttr.net: 2017-01-18 22:43:46,834 - ERROR
> [CommitProcessor:2]
> -org.apache.zookeeper.server.quorum.CommitProcessor.run(CommitProcessor.java:268)
> – Got cxid 0x3a8d expected 0x3ebc for client session id 2051af11af900cc
> clearly something is not right in the new commit processor per session queue
> implementation.
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