incubator-s4-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Gavin Li (Created) (JIRA)" <>
Subject [jira] [Created] (S4-3) Sometimes one process node owns 2 tasks
Date Tue, 11 Oct 2011 03:18:29 GMT
Sometimes one process node owns 2 tasks

                 Key: S4-3
             Project: Apache S4
          Issue Type: Bug
            Reporter: Gavin Li

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
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 (,
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:!default.jspa
For more information on JIRA, see:


View raw message