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https://issues.apache.org/jira/browse/HBASE-5099?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13177386#comment-13177386
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[email protected] commented on HBASE-5099:
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I like this version.

Minor comments below.


src/main/java/org/apache/hadoop/hbase/master/HMaster.java
<https://reviews.apache.org/r/3323/#comment9377>

    Line should wrap after = sign.



src/main/java/org/apache/hadoop/hbase/master/HMaster.java
<https://reviews.apache.org/r/3323/#comment9376>

    The catch block is redundant.



src/test/java/org/apache/hadoop/hbase/master/TestMasterZKSessionRecovery.java
<https://reviews.apache.org/r/3323/#comment9378>

    Javadoc for test class.



src/test/java/org/apache/hadoop/hbase/master/TestMasterZKSessionRecovery.java
<https://reviews.apache.org/r/3323/#comment9379>

    How about giving "hbase.master.zksession.recover.timeout" a much small 
value for the mini cluster so that the timeout value on line 73 can be lowered ?


- Ted


On 2011-12-29 20:41:26, Jimmy Xiang wrote:
bq.  
bq.  -----------------------------------------------------------
bq.  This is an automatically generated e-mail. To reply, visit:
bq.  https://reviews.apache.org/r/3323/
bq.  -----------------------------------------------------------
bq.  
bq.  (Updated 2011-12-29 20:41:26)
bq.  
bq.  
bq.  Review request for hbase, Ted Yu and Michael Stack.
bq.  
bq.  
bq.  Summary
bq.  -------
bq.  
bq.  Per discussion with Ted (on issues), I put up a patch to run 
tryRecoveringExpiredZKSession() in a separate thread and time it out and fail 
the recovery if it is stuck somewhere.
bq.  
bq.  I added a test to test the abort method.  However, for the mini cluster, 
becomeActiveMaster() doesn't succeed so the abort method ends up always 
aborted.  So the actually success recovery is not tested.
bq.  
bq.  
bq.  This addresses bug HBASE-5099.
bq.      https://issues.apache.org/jira/browse/HBASE-5099
bq.  
bq.  
bq.  Diffs
bq.  -----
bq.  
bq.    src/main/java/org/apache/hadoop/hbase/master/HMaster.java a5935a6 
bq.    
src/test/java/org/apache/hadoop/hbase/master/TestMasterZKSessionRecovery.java 
PRE-CREATION 
bq.  
bq.  Diff: https://reviews.apache.org/r/3323/diff
bq.  
bq.  
bq.  Testing
bq.  -------
bq.  
bq.  mvn -PlocalTests -Dtest=TestMaster* clean test
bq.  
bq.  
bq.  Thanks,
bq.  
bq.  Jimmy
bq.  
bq.


                
> 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.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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