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Date: Sun, 10 Apr 2011 00:55:05 +0000 (UTC)
From: "jiraposter@reviews.apache.org (JIRA)" <jira@apache.org>
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Subject: [jira] [Commented] (HBASE-3750) HTablePool.putTable() should call
 table.flushCommits()
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    [ https://issues.apache.org/jira/browse/HBASE-3750?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13018003#comment-13018003 ] 

jiraposter@reviews.apache.org commented on HBASE-3750:
------------------------------------------------------


bq.  On 2011-04-09 22:05:45, Gary Helmling wrote:
bq.  > What is the motivation for calling flushCommits() automatically here?  Are we trying to save client developers from writing buggy code?
bq.  > 
bq.  > The downside I see is that it's easy to envision a case where I use HTablePool for batch loading, but don't want to actually flush after every cycle of: get table, perform operation, return table.  This change would prevent me from doing that and force me either write my own pool or somehow work around it.
bq.  > 
bq.  > In this case it both fails the obviousness test for me and limits what I can easily do as a developer.  What is the upside?  Is it sufficient to balance out the limitations?

This addition is certainly defensive.
Consider what could happen before this patch, putTable() didn't guarantee that the table instance would be put back into the queue (because of size limit of the queue). The user would risk losing data.
Since putTable(tableA) followed by getTable() call doesn't guarantee that tableA would be returned, I wonder how the user planned to finally flush all the buffered data to the underlying table. Consider, that getTable() would always return an HTableInterface instance, he/she couldn't just call getTable() repeatedly and flush the instance's (buffered) data.


bq.  On 2011-04-09 22:05:45, Gary Helmling wrote:
bq.  > /src/main/java/org/apache/hadoop/hbase/client/HTablePool.java, line 126
bq.  > <https://reviews.apache.org/r/573/diff/1/?file=15585#file15585line126>
bq.  >
bq.  >     This seems dangerous and unexpected from a client code point of view.  I wouldn't expect returning the table to a pool to throw a RuntimeException that could potentially cause my client application to exit.

Disclaimer: I didn't invent this piece of code. I got it from HTableFactory.releaseHTableInterface()
If we think that Lars' suggestion is good, we should accept this piece of code.


- Ted


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On 2011-04-09 19:48:31, Ted Yu wrote:
bq.  
bq.  -----------------------------------------------------------
bq.  This is an automatically generated e-mail. To reply, visit:
bq.  https://reviews.apache.org/r/573/
bq.  -----------------------------------------------------------
bq.  
bq.  (Updated 2011-04-09 19:48:31)
bq.  
bq.  
bq.  Review request for hbase and Lars George.
bq.  
bq.  
bq.  Summary
bq.  -------
bq.  
bq.  Currently HTablePool.putTable() doesn't call table.flushCommits()
bq.  If AutoFlush is disabled for table instance, we should call table.flushCommits().
bq.  
bq.  When HTable instance is discarded in putTable(), we should call tableFactory.releaseHTableInterface().
bq.  
bq.  
bq.  This addresses bug HBASE-3750.
bq.      https://issues.apache.org/jira/browse/HBASE-3750
bq.  
bq.  
bq.  Diffs
bq.  -----
bq.  
bq.    /src/main/java/org/apache/hadoop/hbase/client/HTablePool.java 1090500 
bq.  
bq.  Diff: https://reviews.apache.org/r/573/diff
bq.  
bq.  
bq.  Testing
bq.  -------
bq.  
bq.  TestHTablePool passes.
bq.  
bq.  
bq.  Thanks,
bq.  
bq.  Ted
bq.  
bq.


> HTablePool.putTable() should call table.flushCommits()
> ------------------------------------------------------
>
>                 Key: HBASE-3750
>                 URL: https://issues.apache.org/jira/browse/HBASE-3750
>             Project: HBase
>          Issue Type: Bug
>          Components: client
>    Affects Versions: 0.90.1
>            Reporter: Ted Yu
>            Assignee: Ted Yu
>         Attachments: 3750.txt
>
>
> Currently HTablePool.putTable() doesn't call table.flushCommits()
> This may turn out to be surprise for users
> When HTable instance is discarded in putTable(), we should call tableFactory.releaseHTableInterface().

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