[jira] [Commented] (HBASE-11208) Remove the hbase.hstore.blockingStoreFiles setting

["Nicolas Liochon (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-11208?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14004936#comment-14004936 ] 

Nicolas Liochon commented on HBASE-11208:
-----------------------------------------

BTW, by changing this on a YCSB load test, I divided the max latency by 3 (from 45s to 15s). HBASE-11226 adds another division by 3, and this leads us in 5s max latency. YMMV (obviously), but I like what I'm seeing here :-)


> Remove the hbase.hstore.blockingStoreFiles setting
> --------------------------------------------------
>
>                 Key: HBASE-11208
>                 URL: https://issues.apache.org/jira/browse/HBASE-11208
>             Project: HBase
>          Issue Type: Brainstorming
>          Components: Compaction, regionserver
>    Affects Versions: 0.99.0
>            Reporter: Nicolas Liochon
>            Assignee: Nicolas Liochon
>             Fix For: 0.99.0
>
>
> It's a little bit of a provocation, but the rational is:
>  - there are some bugs around the delayed flush. For example, if the periodic scheduler has asked for a delayed flush, and that we need to flush, we will have to wait
>  - if the number of WAL files increases, we won't flush immediately if the blockingFile number has been reached. This impacts the MTTR.
>  - We don't write to limit the compaction impact, but they are many cases where we would want to flush anyway, as the writes cannot wait.
>  - this obviously leads to huge write latency peaks.
> So I'm questioning this setting, it leads to multiple intricate cases, unpredictable write latency, and looks like a workaround for compaction performances. With all the work done on compaction, I think we can get rid of it.  A solution in the middle would be to deprecate it and to set it to a large value...
> Any opinion before I shoot :-) ? 



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