[jira] [Commented] (HBASE-5867) Improve Compaction Throttle Default

["Nicolas Spiegelberg (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-5867?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13268458#comment-13268458 ] 

Nicolas Spiegelberg commented on HBASE-5867:
--------------------------------------------

@stack: this should be a much better out-of-the-box than we currently have.  If anything, we could make the value higher (4 or 8 instead of 2).  However, this should be a substantially-better default than the current.
                
> 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
>         Attachments: D2943.1.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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