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https://issues.apache.org/jira/browse/HBASE-6423?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13500477#comment-13500477
 ] 

Hadoop QA commented on HBASE-6423:
----------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest 
attachment 
  http://issues.apache.org/jira/secure/attachment/12554204/trunk-6423_v2.patch
  against trunk revision .

    {color:green}+1 @author{color}.  The patch does not contain any @author 
tags.

    {color:green}+1 tests included{color}.  The patch appears to include 5 new 
or modified tests.

    {color:red}-1 patch{color}.  The patch command could not apply the patch.

Console output: 
https://builds.apache.org/job/PreCommit-HBASE-Build/3366//console

This message is automatically generated.
                
> Writes should not block reads on blocking updates to memstores
> --------------------------------------------------------------
>
>                 Key: HBASE-6423
>                 URL: https://issues.apache.org/jira/browse/HBASE-6423
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Karthik Ranganathan
>            Assignee: Jimmy Xiang
>         Attachments: trunk-6423.patch, trunk-6423_v2.patch
>
>
> We have a big data use case where we turn off WAL and have a ton of reads and 
> writes. We found that:
> 1. flushing a memstore takes a while (GZIP compression)
> 2. incoming writes cause the new memstore to grow in an unbounded fashion
> 3. this triggers blocking memstore updates
> 4. in turn, this causes all the RPC handler threads to block on writes to 
> that memstore
> 5. we are not able to read during this time as RPC handlers are blocked
> At a higher level, we should not hold up the RPC threads while blocking 
> updates, and we should build in some sort of rate control.

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