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https://issues.apache.org/jira/browse/HBASE-3976?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13448521#comment-13448521
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Mikhail Bautin commented on HBASE-3976:
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Lars: I agree, cache-on-flush is definitely the most useful. This is what we
are now using in production for some workloads.
> 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: Mikhail Bautin
> Priority: Minor
> Attachments: HBASE-3976.patch, HBASE-3976-unconditional.patch,
> HBASE-3976-V3.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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