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https://issues.apache.org/jira/browse/HBASE-23355?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16986570#comment-16986570
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Anoop Sam John commented on HBASE-23355:
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I believe the prefetch feature was added with intent to fetch it on Region open
only. When we go through that old Jira it look so. We have cache on write
config which will govern caching on flush. (This is kind of prefetch only). The
new Jira will do the same for compaction also. So dont think we need new
prefetchOnFlush also. This might be an overkill IMHO.
> Add a conf key to decide which operations can trigger prefetch
> --------------------------------------------------------------
>
> Key: HBASE-23355
> URL: https://issues.apache.org/jira/browse/HBASE-23355
> Project: HBase
> Issue Type: Improvement
> Reporter: chenxu
> Assignee: chenxu
> Priority: Major
>
> Copy the comment from anoop under
> https://issues.apache.org/jira/browse/HBASE-23066?focusedCommentId=16984140&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16984140
> {quote}On a side note, (Not related to this issue) when we have cache on
> write ON as well as prefetch also On, do we do the caching part for the
> flushed files twice? When it is written, its already been added to cache.
> Later as part of HFile reader open, the prefetch threads will again do a read
> and add to cache!
> {quote}
> It's better to have a conf key to decide which operations(flush, compaction,
> regionOpen, bulkload) can trigger the prefetch. In this way, if cacheonwrite
> is enabled, we can exclude the flush and compaction operations when doing
> prefetch.
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