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https://issues.apache.org/jira/browse/HBASE-10449?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13890522#comment-13890522
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Nicolas Liochon commented on HBASE-10449:
-----------------------------------------
Note that we're not exactly changing a default.
The code wanted to do:
{panel}Create up to 'max' (default: 256) threads. Expires them if they are not
used for 10 seconds, excepted for 'core' (default 0) of them. If there is more
than 'max' tasks, queue them.{panel}
Actually it was doing:
{panel}Create a single thread, queue all the tasks for this thread.{panel}
So the patch actually implements that was supposed to be implemented (or tries
to implement it at least :-) ). I
Moreover, it's a regression from HBASE-9917, so actually 96.0 really uses 256
threads. It's a *96.1* issue only. But yes, it does have an impact on
performances, and this impact can be good or bad. That's why I would like it to
be in the .98 RC, and also why I think it's simpler to have the same defaults
on all versions.
Lastly, and unrelated, we didn't have a limit of the number of threads before
the .96. I'm wondering if we don't have an impact if a server hangs. The client
may ends up with all its connections stuck to this server, until it timeouts.
> Wrong execution pool configuration in HConnectionManager
> --------------------------------------------------------
>
> Key: HBASE-10449
> URL: https://issues.apache.org/jira/browse/HBASE-10449
> Project: HBase
> Issue Type: Bug
> Components: Client
> Affects Versions: 0.98.0, 0.99.0, 0.96.1.1
> Reporter: Nicolas Liochon
> Assignee: Nicolas Liochon
> Priority: Critical
> Fix For: 0.98.0, 0.96.2, 0.99.0
>
> Attachments: HBASE-10449.v1.patch
>
>
> There is a confusion in the configuration of the pool. The attached patch
> fixes this. This may change the client performances, as we were using a
> single thread.
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