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https://issues.apache.org/jira/browse/HADOOP-2636?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12565216#action_12565216
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Billy Pearson commented on HADOOP-2636:
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Copied from HADOOP-2615
I got a second ideal on this to help with hot spots
If we could add a way to set a priority for compaction's this would help with
the hot spots regions building up to many map files flushes.
Example if we have a region with 25 map files and one with 10
Region with 25 map files would have a priority of 25
and the one with 10 map files have a priority of 10 we would compact the region
with 25 before 10
If we could add/update the priority when we do a flush then the compactor could
work on region that need it the most in order.
> [hbase] Make cache flush triggering less simplistic
> ---------------------------------------------------
>
> Key: HADOOP-2636
> URL: https://issues.apache.org/jira/browse/HADOOP-2636
> Project: Hadoop Core
> Issue Type: Improvement
> Components: contrib/hbase
> Affects Versions: 0.16.0
> Reporter: stack
> Assignee: Jim Kellerman
> Fix For: 0.17.0
>
> Attachments: patch.txt, patch.txt, patch.txt, patch.txt, patch.txt,
> patch.txt, patch.txt, patch.txt
>
>
> When flusher runs -- its triggered when the sum of all Stores in a Region > a
> configurable max size -- we flush all Stores though a Store memcache might
> have but a few bytes.
> I would think Stores should only dump their memcache disk if they have some
> substance.
> The problem becomes more acute, the more families you have in a Region.
> Possible behaviors would be to dump the biggest Store only, or only those
> Stores > 50% of max memcache size. Behavior would vary dependent on the
> prompt that provoked the flush. Would also log why the flush is running:
> optional or > max size.
> This issue comes out of HADOOP-2621.
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