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https://issues.apache.org/jira/browse/HBASE-69?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12567957#action_12567957
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Billy Pearson commented on HBASE-69:
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I am still seeing a hlog build up problem
example I see these a lot after a job is done and the server are idle
{code}
2008-02-11 22:46:44,032 INFO org.apache.hadoop.hbase.HStore: Not flushing cache
for 519281761/anchor because it has 0 entries
2008-02-11 22:46:44,032 DEBUG org.apache.hadoop.hbase.HRegion: Finished
memcache flush for store 519281761/anchor in 1ms, sequenceid=131598230
{code}
I assume this is a optional flush which is good to have but if there is no
entries can we update the columns current sequence id for that column to our
current max sequence id so we can remove the old logs after the next hlog ?
What I am seeing is low to no updated columns never get a memcache flush so
there sequence id never changes (unless there is a split) and the old hlogs
never get removed.
> [hbase] Make cache flush triggering less simplistic
> ---------------------------------------------------
>
> Key: HBASE-69
> URL: https://issues.apache.org/jira/browse/HBASE-69
> Project: Hadoop HBase
> Issue Type: Improvement
> Components: regionserver
> Reporter: stack
> Assignee: Jim Kellerman
> Fix For: 0.2.0
>
> Attachments: patch.txt, patch.txt, patch.txt, 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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