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Posted to dev@curator.apache.org by "Jordan Zimmerman (JIRA)" <ji...@apache.org> on 2019/06/05 13:39:00 UTC
[jira] [Commented] (CURATOR-527) Concurrency issue in LockInternals
[ https://issues.apache.org/jira/browse/CURATOR-527?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16856721#comment-16856721 ]
Jordan Zimmerman commented on CURATOR-527:
------------------------------------------
The situation as you describe cannot happen. If the node doesn't exist when {{getData()}} is called ZooKeeper will throw {{NoNodeException}} which is handled by LockInternals. If the node does exist but is then deleted, the watcher will get called and then LockInternals handles that.
Please provide a test that shows the problem you're having.
> Concurrency issue in LockInternals
> ----------------------------------
>
> Key: CURATOR-527
> URL: https://issues.apache.org/jira/browse/CURATOR-527
> Project: Apache Curator
> Issue Type: Bug
> Components: Recipes
> Affects Versions: 2.12.0
> Environment: Curator 2.12.0
> zookeeper 3.4.14
> Reporter: Kim Jaechang
> Priority: Major
>
> I'm using InterProcessMutex and InterProcessMutex often failed to acquire lock.
> In LockInternals.internalLockLoop(), watcher is registered to zookeeper and call wait() like below
> {code:java}
> client.getData().usingWatcher(watcher).forPath(previousSequencePath);
> if ( millisToWait != null )
> {
> millisToWait -= (System.currentTimeMillis() - startMillis);
> startMillis = System.currentTimeMillis();
> if ( millisToWait <= 0 )
> {
> doDelete = true; // timed out - delete our node
> break;
> }
> wait(millisToWait);
> }
> else
> {
> wait();
> }
> {code}
> In my case, my program is waiting previousSequencePath=_c_50f10103-c19e-45f4-8cc3-ba686ea452fe-lock-0000000760 to be deleted.
> But _c_50f10103-c19e-45f4-8cc3-ba686ea452fe-lock-0000000760 is deleted between client.getData() and wait().
> if _c_50f10103-c19e-45f4-8cc3-ba686ea452fe-lock-0000000760 is deleted when
> client.getData().usingWatcher(watcher).forPath(previousSequencePath) is called, it will throw Exception but it was exist at that time.
> I'm using Curator 2.12.0 but latest version seems to have same issue.
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