[jira] [Resolved] (HBASE-26274) Create an option to reintroduce BlockCache to mapreduce job

["Tak-Lon (Stephen) Wu (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HBASE-26274?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tak-Lon (Stephen) Wu resolved HBASE-26274.
------------------------------------------
    Resolution: Fixed

> Create an option to reintroduce BlockCache to mapreduce job
> -----------------------------------------------------------
>
>                 Key: HBASE-26274
>                 URL: https://issues.apache.org/jira/browse/HBASE-26274
>             Project: HBase
>          Issue Type: Bug
>          Components: BlockCache, HFile, mapreduce
>    Affects Versions: 3.0.0-alpha-1, 2.4.6
>            Reporter: Tak-Lon (Stephen) Wu
>            Assignee: Tak-Lon (Stephen) Wu
>            Priority: Major
>             Fix For: 2.5.0, 2.3.7, 2.4.7, 3.0.0-alpha-1
>
>
> In HBASE-21498 (see [this commit|https://github.com/apache/hbase/commit/27a0f205c52f83fe7500ee2ffc6cf6582f565a63#diff-8a3e39e6df1afe47811fc17702da598fe0d80496d66e579bea4bd224c6d8da03R218], it change the behavior that only region server can initialize on-heap BlockCache/LruBlockCache, this should be the right change for HMaster. 
> Other downstream dependency that uses getScanner from a file-based region and read HStore/HFile lost the BlockCache for caching INDEX/LEAF_INDEX (at least still a problem with HBase-2.4) after this change (it worked before) and caused performance impact with 2x slower.
> One way to bring back the performance is to allow non-RS and non-HMaster can use a compact version of blockcache with smaller memory and less hbase internal configuration. 
> Or if we can find a way to cache or skip reading the same {{LEAF_INDEX}} when scanning the DATA block with HFile. 



--
This message was sent by Atlassian Jira
(v8.3.4#803005)