[jira] [Commented] (HBASE-23355) Add a conf key to decide which operations can trigger prefetch

["Anoop Sam John (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-23355?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16985821#comment-16985821 ] 

Anoop Sam John commented on HBASE-23355:
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Do we need a new conf key? Why?  We can decide based on the existing conf values only?
When cache on write is true, dont do the prefetch for flushed files. When the new conf that u added in other jira is true, dont do same for compaction also.  Hard to know at the HFile reader open time what is the context?

> 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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