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https://issues.apache.org/jira/browse/ZOOKEEPER-1448?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Botond Hejj updated ZOOKEEPER-1448:
-----------------------------------
Attachment: ZOOKEEPER-1448.patch
Updated unittest to remove log4j dependency
> Node+Quota creation in transaction log can crash leader startup
> ---------------------------------------------------------------
>
> Key: ZOOKEEPER-1448
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1448
> Project: ZooKeeper
> Issue Type: Bug
> Components: server
> Affects Versions: 3.3.5
> Reporter: Botond Hejj
> Assignee: Flavio Junqueira
> Priority: Critical
> Fix For: 3.4.6
>
> Attachments: ZOOKEEPER-1448_branch3.3.patch, ZOOKEEPER-1448.patch,
> ZOOKEEPER-1448.patch, ZOOKEEPER-1448.patch, ZOOKEEPER-1448.patch,
> ZOOKEEPER-1448.patch
>
>
> Hi,
> I've found a bug in zookeeper related to quota creation which can shutdown
> zookeeper leader on startup.
> Steps to reproduce:
> 1. create /quota_bug
> 2. setquota -n 10000 /quota_bug
> 3. stop the whole ensemble (the previous operations should be in the
> transaction log)
> 4. start all the servers
> 5. the elected leader will shutdown with an exception (Missing stat node for
> count /zookeeper/quota/quota_bug/zookeeper_
> stats)
> I've debugged a bit what happening and I found the following problem:
> On startup each server loads the last snapshot and replays the last
> transaction log. While doing this it fills up the pTrie variable of the
> DataTree with the path of the nodes which have quota.
> After the leader is elected the leader servers loads the snapshot and last
> transaction log but it doesn't clean up the pTrie variable. This means it
> still contains the "/quota_bug" path. Now when the "create /quota_bug" is
> processed from the transaction log the DataTree already thinks that the quota
> nodes ("/zookeeper/quota/quota_bug/zookeeper_limits" and
> "/zookeeper/quota/quota_bug/zookeeper_stats") are created but those node
> creation actually comes later in the transaction log. This leads to the
> missing stat node exception.
> I think clearing the pTrie should solve this problem.
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