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https://issues.apache.org/jira/browse/HBASE-9467?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13766885#comment-13766885
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Todd Lipcon commented on HBASE-9467:
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I don't have time to look at the patch itself, but one thing that comes to
mind: is this a compatible change? Or do you need to add a new client parameter
of some time that tells the server that it knows how to handle the new
exception? It would be bad if existing clients all started getting some
ClassNotFoundException trying to unwrap the new exception type, and actually
failing rather than retrying. I don't know if that happens, but worth double
checking (eg run YCSB with an old client against a new server)
> 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
> Assignee: Feng Honghua
> Attachments: HBASE-9467-trunk-v0.patch
>
>
> 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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