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https://issues.apache.org/jira/browse/HBASE-3976?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13182732#comment-13182732
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Zhihong Yu commented on HBASE-3976:
-----------------------------------

This was integrated on 17/Jun/11 11:00 and the status is Open.
That's confusing.
                
> Disable Block Cache On Compactions
> ----------------------------------
>
>                 Key: HBASE-3976
>                 URL: https://issues.apache.org/jira/browse/HBASE-3976
>             Project: HBase
>          Issue Type: Improvement
>          Components: regionserver
>    Affects Versions: 0.90.3
>            Reporter: Karthick Sankarachary
>            Assignee: Nicolas Spiegelberg
>            Priority: Minor
>         Attachments: HBASE-3976-V3.patch, HBASE-3976-unconditional.patch, 
> HBASE-3976.patch
>
>
> Is there a good reason to believe that caching blocks during compactions is 
> beneficial? Currently, if block cache is enabled on a certain family, then 
> every time it's compacted, we load all of its blocks into the (LRU) cache, at 
> the expense of the legitimately hot ones.
> As a matter of fact, this concern was raised earlier in HBASE-1597, which 
> rightly points out that, "we should not bog down the LRU with unneccessary 
> blocks" during compaction. Even though that issue has been marked as "fixed", 
> it looks like it ought to be reopened.
> Should we err on the side of caution and not cache blocks during compactions 
> period (as illustrated in the attached patch)? Or, can we be selectively 
> aggressive about what blocks do get cached during compaction (e.g., only 
> cache those blocks from the recent files)?

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