We are using zookeeper 3.5.1. It seems from your message that we are
not vulnerable to this issue?

On Wed, Aug 31, 2016 at 10:44 AM, Lei Xia (JIRA) <[email protected]> wrote:
>
>     [ 
> https://issues.apache.org/jira/browse/HELIX-527?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15452861#comment-15452861
>  ]
>
> Lei Xia commented on HELIX-527:
> -------------------------------
>
> We may need to reevaluate this issue and figure out the solution.  Assigned 
> to me, and I will spend some time on this issue.
>
>> Mitigate zookeeper watch leak
>> -----------------------------
>>
>>                 Key: HELIX-527
>>                 URL: https://issues.apache.org/jira/browse/HELIX-527
>>             Project: Apache Helix
>>          Issue Type: Bug
>>            Reporter: Zhen Zhang
>>
>> On investigating zookeeper watch leakage problem, it turns out to be a 
>> zookeeper issue:
>> https://issues.apache.org/jira/browse/ZOOKEEPER-442
>> For zookeeper before 3.5.0, we can't remove watches that are no longer of 
>> interests. The only way to remove a watch is to trigger it; that is, if it 
>> is a DataWatch, we need to trigger a data change on the watching path, or if 
>> it is a ChildWatch, we need to trigger a child change on the watching path. 
>> Unfortunately, if we are watching a path that has been deleted, unless we 
>> re-create the path, there is no way we can remove the watch.
>> Here are some of the most common scenarios where we will have dead zookeeper 
>> watches on zookeeper server side even though we unregister all the listeners 
>> on the zookeeper client side:
>> - When we drop a resource group from a cluster, we may have dead watches on 
>> ideal-state, participant current-state, and external-view
>> - When we remove an instance from a cluster, we may have dead watches on 
>> current-state, participant-config, and participant messages
>> - When we use property store with caches enabled by zookeeper watches, we 
>> may have dead watches on all removed paths
>
>
>
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