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Date: Tue, 15 May 2012 23:55:10 +0000 (UTC)
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Subject: [jira] [Commented] (HBASE-5867) Improve Compaction Throttle Default
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    [ https://issues.apache.org/jira/browse/HBASE-5867?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13276347#comment-13276347 ] 

Hudson commented on HBASE-5867:
-------------------------------

Integrated in HBase-TRUNK-on-Hadoop-2.0.0 #5 (See [https://builds.apache.org/job/HBase-TRUNK-on-Hadoop-2.0.0/5/])
    [HBASE-5867] Improve Compaction Throttle Default

Summary:
We recently had a production issue where our compactions fell
behind because our compaction throttle was improperly tuned and
accidentally upgraded all compactions to the large pool. The default
from HBASE-3877 makes 1 bad assumption: the default number of flushed
files in a compaction. MinFilesToCompact should be taken into
consideration. As a default, it is less damaging for the large thread
to be slightly higher than it needs to be and only get timed-majors
versus having everything accidentally promoted.

Test Plan:  - mvn test

Reviewers: JIRA, Kannan, Liyin
Reviewed By: Kannan
CC: stack

Differential Revision: https://reviews.facebook.net/D2943 (Revision 1338809)

     Result = FAILURE
nspiegelberg : 
Files : 
* /hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/CompactSplitThread.java
* /hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/Store.java

                
> Improve Compaction Throttle Default
> -----------------------------------
>
>                 Key: HBASE-5867
>                 URL: https://issues.apache.org/jira/browse/HBASE-5867
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Nicolas Spiegelberg
>            Assignee: Nicolas Spiegelberg
>            Priority: Minor
>             Fix For: 0.96.0
>
>         Attachments: D2943.1.patch, HBASE-5867-trunk.patch
>
>
> We recently had a production issue where our compactions fell behind because our compaction throttle was improperly tuned and accidentally upgraded all compactions to the large pool.  The default from HBASE-3877 makes 1 bad assumption: the default number of flushed files in a compaction.  Currently the algorithm is:
> throttleSize ~= flushSize * 2
> This assumes that the basic compaction utilizes 3 files and that all 3 files are compressed.  In this case, "hbase.hstore.compaction.min" == 6 && the values were not very compressible.  Both conditions should be taken into consideration.  As a default, it is less damaging for the large thread to be slightly higher than it needs to be versus having everything accidentally promoted.

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