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https://issues.apache.org/jira/browse/HBASE-5099?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13177404#comment-13177404
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Zhihong Yu commented on HBASE-5099:
-----------------------------------

@Jimmy:
Do you mind producing a patch for 0.92 ?
I got the following when I tried to apply patch v5 to 0.92:
{code}
1 out of 3 hunks FAILED -- saving rejects to file 
src/main/java/org/apache/hadoop/hbase/master/HMaster.java.rej
{code}

Also there is no test category in 0.92:
{code}
[ERROR] 
/Users/zhihyu/92hbase/src/test/java/org/apache/hadoop/hbase/master/TestMasterZKSessionRecovery.java:[27,30]
 cannot find symbol
[ERROR] symbol  : class MediumTests
[ERROR] location: package org.apache.hadoop.hbase
{code}

This is a whitespace at line 41 in TestMasterZKSessionRecovery - I can remove 
it at time of integration.

Nice work.
                
> ZK event thread waiting for root region while server shutdown handler waiting 
> for event thread to finish distributed log splitting to recover the region 
> sever the root region is on
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-5099
>                 URL: https://issues.apache.org/jira/browse/HBASE-5099
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 0.92.0, 0.94.0
>            Reporter: Jimmy Xiang
>            Assignee: Jimmy Xiang
>         Attachments: ZK-event-thread-waiting-for-root.png, 
> distributed-log-splitting-hangs.png, hbase-5099-v2.patch, 
> hbase-5099-v3.patch, hbase-5099-v4.patch, hbase-5099-v5.patch, 
> hbase-5099.patch
>
>
> A RS died.  The ServerShutdownHandler kicked in and started the logspliting.  
> SpliLogManager
> installed the tasks asynchronously, then started to wait for them to complete.
> The task znodes were not created actually.  The requests were just queued.
> At this time, the zookeeper connection expired.  HMaster tried to recover the 
> expired ZK session.
> During the recovery, a new zookeeper connection was created.  However, this 
> master became the
> new master again.  It tried to assign root and meta.
> Because the dead RS got the old root region, the master needs to wait for the 
> log splitting to complete.
> This waiting holds the zookeeper event thread.  So the async create split 
> task is never retried since
> there is only one event thread, which is waiting for the root region assigned.

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