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Date: Mon, 11 Feb 2008 14:20:08 -0800 (PST)
From: "Jim Kellerman (JIRA)" <jira@apache.org>
To: hbase-dev@hadoop.apache.org
Subject: [jira] Commented: (HBASE-69) [hbase] Make cache flush triggering
 less simplistic
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    [ https://issues.apache.org/jira/browse/HBASE-69?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12567846#action_12567846 ] 

Jim Kellerman commented on HBASE-69:
------------------------------------

> Billy Pearson - 11/Feb/08 02:00 PM
> I get Blocking updates messages but no flushing happens so everything gos on hold and no new
> transaction happen all my threads get blocked

This logic is currently very unsophisticated. I'll try to come up with something better in the next patch. In the mean time, setting hbase.hregion.memcache.block.multiplier to (at least) the number of families should make things work.

> [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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