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https://issues.apache.org/jira/browse/HBASE-5081?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zhihong Yu updated HBASE-5081:
------------------------------

    Comment: was deleted

(was: -1 overall.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12508259/patch_for_92.txt
  against trunk revision .

    +1 @author.  The patch does not contain any @author tags.

    -1 tests included.  The patch doesn't appear to include any new or modified 
tests.
                        Please justify why no new tests are needed for this 
patch.
                        Also please list what manual steps were performed to 
verify this patch.

    -1 javadoc.  The javadoc tool appears to have generated -152 warning 
messages.

    +1 javac.  The applied patch does not increase the total number of javac 
compiler warnings.

    -1 findbugs.  The patch appears to introduce 76 new Findbugs (version 
1.3.9) warnings.

    +1 release audit.  The applied patch does not increase the total number of 
release audit warnings.

     -1 core tests.  The patch failed these unit tests:
                       org.apache.hadoop.hbase.client.TestInstantSchemaChange
                  org.apache.hadoop.hbase.mapred.TestTableMapReduce
                  org.apache.hadoop.hbase.mapreduce.TestHFileOutputFormat
                  org.apache.hadoop.hbase.master.TestSplitLogManager

Test results: 
https://builds.apache.org/job/PreCommit-HBASE-Build/569//testReport/
Findbugs warnings: 
https://builds.apache.org/job/PreCommit-HBASE-Build/569//artifact/trunk/patchprocess/newPatchFindbugsWarnings.html
Console output: https://builds.apache.org/job/PreCommit-HBASE-Build/569//console

This message is automatically generated.)
    
> Distributed log splitting deleteNode races againsth splitLog retry 
> -------------------------------------------------------------------
>
>                 Key: HBASE-5081
>                 URL: https://issues.apache.org/jira/browse/HBASE-5081
>             Project: HBase
>          Issue Type: Bug
>          Components: wal
>    Affects Versions: 0.92.0, 0.94.0
>            Reporter: Jimmy Xiang
>            Assignee: Jimmy Xiang
>             Fix For: 0.92.0
>
>         Attachments: distributed-log-splitting-screenshot.png, 
> hbase-5081-patch-v6.txt, hbase-5081-patch-v7.txt, 
> hbase-5081_patch_for_92_v4.txt, hbase-5081_patch_v5.txt, patch_for_92.txt, 
> patch_for_92_v2.txt, patch_for_92_v3.txt
>
>
> Recently, during 0.92 rc testing, we found distributed log splitting hangs 
> there forever.  Please see attached screen shot.
> I looked into it and here is what happened I think:
> 1. One rs died, the servershutdownhandler found it out and started the 
> distributed log splitting;
> 2. All three tasks failed, so the three tasks were deleted, asynchronously;
> 3. Servershutdownhandler retried the log splitting;
> 4. During the retrial, it created these three tasks again, and put them in a 
> hashmap (tasks);
> 5. The asynchronously deletion in step 2 finally happened for one task, in 
> the callback, it removed one
> task in the hashmap;
> 6. One of the newly submitted tasks' zookeeper watcher found out that task is 
> unassigned, and it is not
> in the hashmap, so it created a new orphan task.
> 7.  All three tasks failed, but that task created in step 6 is an orphan so 
> the batch.err counter was one short,
> so the log splitting hangs there and keeps waiting for the last task to 
> finish which is never going to happen.
> So I think the problem is step 2.  The fix is to make deletion sync, instead 
> of async, so that the retry will have
> a clean start.
> Async deleteNode will mess up with split log retrial.  In extreme situation, 
> if async deleteNode doesn't happen
> soon enough, some node created during the retrial could be deleted.
> deleteNode should be sync.

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