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jirapos...@reviews.apache.org commented on HBASE-5986:
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src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java
<https://reviews.apache.org/r/5133/#comment17261>

    I was asking how do we convey the fact that MetaScanner has timed out to 
client.
    
    I don't see exception being thrown which contains timeout information.


- Ted


On 2012-05-16 01:53:09, enis wrote:
bq.  
bq.  -----------------------------------------------------------
bq.  This is an automatically generated e-mail. To reply, visit:
bq.  https://reviews.apache.org/r/5133/
bq.  -----------------------------------------------------------
bq.  
bq.  (Updated 2012-05-16 01:53:09)
bq.  
bq.  
bq.  Review request for hbase.
bq.  
bq.  
bq.  Summary
bq.  -------
bq.  
bq.  We found this issue when running large scale ingestion tests for 
HBASE-5754. The problem is that the .META. table updates are not atomic while 
splitting a region. In SplitTransaction, there is a time lap between the 
marking the parent offline, and adding of daughters to the META table. This can 
result in clients using MetaScanner, of HTable.getStartEndKeys (used by the 
TableInputFormat) missing regions which are made just offline, but the 
daughters are not added yet.
bq.  
bq.  This patch is the approach 2 mentioned in the issue comments, mainly 
during META scan, if we detect that the region is split, we block until the 
information for the child regions are available in META and manually feed those 
rows to the MetaScanner. Although approach 3 (using local region transactions) 
seems cleaner, they are not available under branch 0.92, which I think should 
also incorporate this fix. I'll provide ports once we are clear for trunk. 
bq.  
bq.  Also this patch does not fix MetaReader (see 
https://issues.apache.org/jira/browse/HBASE-3475). 
bq.  
bq.  
bq.  This addresses bug HBASE-5986.
bq.      https://issues.apache.org/jira/browse/HBASE-5986
bq.  
bq.  
bq.  Diffs
bq.  -----
bq.  
bq.    src/main/java/org/apache/hadoop/hbase/catalog/MetaEditor.java 8873512 
bq.    src/main/java/org/apache/hadoop/hbase/client/HTable.java b8290e4 
bq.    src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java f404999 
bq.    
src/test/java/org/apache/hadoop/hbase/regionserver/TestEndToEndSplitTransaction.java
 a8091e6 
bq.  
bq.  Diff: https://reviews.apache.org/r/5133/diff
bq.  
bq.  
bq.  Testing
bq.  -------
bq.  
bq.  added extensive tests under TestEndToEndSplitTranscation, and ran existing 
unit tests. 
bq.  
bq.  
bq.  Thanks,
bq.  
bq.  enis
bq.  
bq.


                
> Clients can see holes in the META table when regions are being split
> --------------------------------------------------------------------
>
>                 Key: HBASE-5986
>                 URL: https://issues.apache.org/jira/browse/HBASE-5986
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 0.92.1, 0.96.0, 0.94.1
>            Reporter: Enis Soztutar
>            Assignee: Enis Soztutar
>         Attachments: HBASE-5986-test_v1.patch
>
>
> We found this issue when running large scale ingestion tests for HBASE-5754. 
> The problem is that the .META. table updates are not atomic while splitting a 
> region. In SplitTransaction, there is a time lap between the marking the 
> parent offline, and adding of daughters to the META table. This can result in 
> clients using MetaScanner, of HTable.getStartEndKeys (used by the 
> TableInputFormat) missing regions which are made just offline, but the 
> daughters are not added yet. 
> This is also related to HBASE-4335. 

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