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https://issues.apache.org/jira/browse/HBASE-2021?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12793028#action_12793028
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Andrew Purtell commented on HBASE-2021:
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bq. Would you agree to put this into HServerLoad? Seems a natural fit to add it 
there. 

+1

> Add compaction details to master UI
> -----------------------------------
>
>                 Key: HBASE-2021
>                 URL: https://issues.apache.org/jira/browse/HBASE-2021
>             Project: Hadoop HBase
>          Issue Type: Improvement
>            Reporter: Lars George
>            Assignee: Lars George
>            Priority: Minor
>             Fix For: 0.21.0
>
>         Attachments: HBASE-2021.patch
>
>
> There are two issues with this, first to detect that there is a compaction 
> needed. You can currently use the little helper util that checks if a table 
> has at least one colfam with more than one store file. I though about 
> scanning all tables and all colfams in each and then compute the 
> "fragmentation" ratio as a percentage of colfams with more than one store to 
> the total number of colfams. That gives a "Table xyz is 33% fragmented" 
> output. While minor percentage are normal under insert operations it is still 
> important to know how bad the fragmentation is overall.
> Another idea is to weigh the number of files per store too, so that if you 
> have two per colfam it is considered "low" and if you have more, for example 
> 6-8 it is considered "high". Not sure how that can be done yet but noting the 
> idea down here.
> Of course seeing the .META. fragmentation is useful to quickly debug 
> performance issues (as JD told me on IRC).
> The other issue is that when you have started a compaction you have no idea 
> how far it is and if it is still in progress. One indication of course is the 
> above value. If it is 0% then all is done. But if you are at say 23%, is it 
> still compacting? We could have a simple status that compactions are still in 
> progress.

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