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https://issues.apache.org/jira/browse/HBASE-9467?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13762680#comment-13762680
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Feng Honghua commented on HBASE-9467:
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[~nkeywal] Can we provide a percentage config which means how big the sub-set
of handler threads any region's requests can use? And for any region we can
hash its region name to a determined start index of the handler thread array,
and the percentage config together with the count the handler threads
determines the count of the sub-array of the handler threads to serve this
region's requests. This way any region at worst can only saturate its sub-set
of handler threads without impacting all the handler threads, and hence
somewhat mitigates the symptom
> write can be totally blocked temporarily by a write-heavy region
> ----------------------------------------------------------------
>
> Key: HBASE-9467
> URL: https://issues.apache.org/jira/browse/HBASE-9467
> Project: HBase
> Issue Type: Improvement
> Reporter: Feng Honghua
> Priority: Minor
>
> Write to a region can be blocked temporarily if the memstore of that region
> reaches the threshold(hbase.hregion.memstore.block.multiplier *
> hbase.hregion.flush.size) until the memstore of that region is flushed.
> For a write-heavy region, if its write requests saturates all the handler
> threads of that RS when write blocking for that region occurs, requests of
> other regions/tables to that RS also can't be served due to no available
> handler threads...until the pending writes of that write-heavy region are
> served after the flush is done. Hence during this time period, from the RS
> perspective it can't serve any request from any table/region just due to a
> single write-heavy region.
> This sounds not very reasonable, right? Maybe write requests from a region
> can only be served by a sub-set of the handler threads, and then write
> blocking of any single region can't lead to the scenario mentioned above?
> Comment?
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