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Posted to dev@hbase.apache.org by "Andrew Purtell (JIRA)" <ji...@apache.org> on 2009/12/16 01:05:20 UTC

[jira] Resolved: (HBASE-1813) Remove compaction governor

     [ https://issues.apache.org/jira/browse/HBASE-1813?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrew Purtell resolved HBASE-1813.
-----------------------------------

       Resolution: Fixed
    Fix Version/s: 0.20.3

Resolved by other issues.

> Remove compaction governor
> --------------------------
>
>                 Key: HBASE-1813
>                 URL: https://issues.apache.org/jira/browse/HBASE-1813
>             Project: Hadoop HBase
>          Issue Type: Bug
>            Reporter: stack
>             Fix For: 0.20.3, 0.21.0
>
>
> It might make sense now undoing the compaction governor:
> From the list (read in reverse):
> {code}
> Andrew Purtell
>  to hbase-user
> 	
> show details 10:18 PM (7 minutes ago)
> 	
> I had a similar thought, that this could be removed in 0.21.
>   - Andy
> ________________________________
> From: stack <st...@duboce.net>
> To: hbase-user@hadoop.apache.org
> Sent: Wednesday, September 2, 2009 8:13:06 PM
> Subject: Re: Compactions no longer limited
> Andrew:
> Maybe now that in 0.20.0 we only run compaction on open IFF the region has
> references, may be this facility is no longer needed?
> St.Ack
> On Wed, Sep 2, 2009 at 6:05 PM, Andrew Purtell <ap...@apache.org> wrote:
> > Hi Ken,
> >
> > Compactions are serviced by a thread which sleeps for a configurable
> > interval and then wakes to do work. As compaction requests are raised, they
> > are queued and the thread is signaled and wakes early. When a region server
> > first starts up, a limit is imposed on how many compaction requests can be
> > serviced from the queue before the thread goes back to sleep. The limit is
> > gradually relaxed. The net effect is to draw out compactions over an initial
> > "safe mode". The reason this is done is to limit load on DFS when the
> > cluster is starting. Compactions during this period often process flushes
> > from the last shutdown and can well trigger splits. Around the 0.19
> > timeframe I had a 25 node test cluster pushing 1000 regions per node.
> > Startup compaction/split activity would crush DFS and prevent successful
> > (re)starts. The mechanism described here solved that issue.
> >
> >    - Andy
> {code}

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