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https://issues.apache.org/jira/browse/HBASE-23066?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16993690#comment-16993690
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Sean Busbey commented on HBASE-23066:
-------------------------------------
I reverted d561130e82 on master branch because after revert
{{TestCacheOnWrite}} consistently passes. with d561130e82 it consistently fails.
{code}
commit ec9bd20ec8423d49641d0d30704eaee178480d0e (HEAD -> master, origin/master,
origin/HEAD)
Author: Sean Busbey <[email protected]>
Date: Wed Dec 11 10:17:46 2019 -0600
Revert "HBASE-23066 Allow cache on write during compactions when
prefetching is (#919)"
TestCacheOnWrite failing all the time.
This reverts commit d561130e82c5956f0dd9fff5c6f6240a686d3d6a.
{code}
Please ensure the test works reliably before pushing again. Also please set the
contributor info as the git author using {{--author "Some User
<[email protected]"}}
> Allow cache on write during compactions when prefetching is enabled
> -------------------------------------------------------------------
>
> Key: HBASE-23066
> URL: https://issues.apache.org/jira/browse/HBASE-23066
> Project: HBase
> Issue Type: Improvement
> Components: Compaction, regionserver
> Affects Versions: 1.4.10
> Reporter: Jacob LeBlanc
> Assignee: Jacob LeBlanc
> Priority: Minor
> Fix For: 2.3.0, 1.6.0
>
> Attachments: HBASE-23066.patch, performance_results.png,
> prefetchCompactedBlocksOnWrite.patch
>
>
> In cases where users care a lot about read performance for tables that are
> small enough to fit into a cache (or the cache is large enough),
> prefetchOnOpen can be enabled to make the entire table available in cache
> after the initial region opening is completed. Any new data can also be
> guaranteed to be in cache with the cacheBlocksOnWrite setting.
> However, the missing piece is when all blocks are evicted after a compaction.
> We found very poor performance after compactions for tables under heavy read
> load and a slower backing filesystem (S3). After a compaction the prefetching
> threads need to compete with threads servicing read requests and get
> constantly blocked as a result.
> This is a proposal to introduce a new cache configuration option that would
> cache blocks on write during compaction for any column family that has
> prefetch enabled. This would virtually guarantee all blocks are kept in cache
> after the initial prefetch on open is completed allowing for guaranteed
> steady read performance despite a slow backing file system.
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