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https://issues.apache.org/jira/browse/HBASE-14651?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14986224#comment-14986224
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stack edited comment on HBASE-14651 at 11/2/15 11:48 PM:
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The similarity in the two graphs is uncanny. I was expecting some difference. 
Do you have test runs that show other that what I found? Do you have 
recommendation on how I might make this patch look good? Thanks.


was (Author: stack):
The similarity in the two graphs is uncanny. Do you have test runs that show 
other that what I found?

> Default minimum compaction size is too high
> -------------------------------------------
>
>                 Key: HBASE-14651
>                 URL: https://issues.apache.org/jira/browse/HBASE-14651
>             Project: HBase
>          Issue Type: New Feature
>            Reporter: Vladimir Rodionov
>            Assignee: Vladimir Rodionov
>         Attachments: HBASE-14651-v1.patch, HBASE-14651-v2.patch, bytes.png, 
> files.png
>
>
> *hbase.hstore.compaction.min.size* defines minimum selection size which is 
> always eligible for minor compaction (no compaction ratio check is performed 
> on such file selections). Default size is equals to memstore flush size 
> (128MB).  First of all, even this value is too high for some (many) 
> deployments, especially for write intensive, because of  a small sizes of a 
> memstore flushes, and if user increases memstore flush size (they usually set 
> it to at least 256MB), they have no idea how will it impact the overall 
> compaction process efficiency. With 256MB of minimum size to compact, 
> compactor most of the time skips necessary file ratio checks and this will 
> result in increased read/write IO during compactions, because of the 
> unbalanced selections where relatively large files can be mixed with a newly 
> created small store files. I think we should set this default minimum  to 
> 64MB and not to link it to memstore flush size at all.     



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