[
https://issues.apache.org/jira/browse/S4-3?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Gavin Li updated S4-3:
----------------------
Comment: was deleted
(was: Attach the fix to the ConnectionLossException of zk.create() by checking
if we have actually created the ephemeral znode successfully.
This change has been tested in my dev environment by adding some pause before
the create() and stopping the zookeeper server to simulate the time out
scenario. Handling of InterruptedException is also improved to make the thread
able to interrupt.)
> Sometimes one process node owns 2 tasks
> ---------------------------------------
>
> Key: S4-3
> URL: https://issues.apache.org/jira/browse/S4-3
> Project: Apache S4
> Issue Type: Bug
> Reporter: Gavin Li
> Assignee: Gavin Li
> Attachments: losconnfix2, losconnfix2, s4_loscon_fix
>
>
> When using S4, we found sometimes it ends up with one process node owns 2
> tasks. I did some investigation, it seems that the handling of
> ConnectionLossException when creating the ephemeral node is problematic.
> Sometimes when the response from zookeeper server times out,
> zookeeper.create() will fail with ConnectionLossException while the creation
> request might already be sent to server(see
> http://svn.apache.org/viewvc/hadoop/zookeeper/trunk/src/java/main/org/apache/zookeeper/ClientCnxn.java
> line 830). From our logs this is the case we ran into.
> Maybe we should handle it in the way that HBase is handling it
> (http://svn.apache.org/viewvc/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java?view=markup),
> just simply exit the process when got that exception to let the whole
> process restart.
> To be more clear, what happened was: a process node called zookeeper.create()
> to acquire a task, the request was successfully sent to zookeeper server, but
> the zookeeper IO loop timed out before the response came. So the
> zookeeper.create() failed with ConnectionLossException. Then the process node
> ignored this exception and tried to acquire another task. Then it got 2 tasks.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
