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Posted to issues@hbase.apache.org by "Nicolas Liochon (JIRA)" <ji...@apache.org> on 2014/07/10 17:29:04 UTC
[jira] [Assigned] (HBASE-11492) The servers do not honnor the
tcpNoDelay option
[ https://issues.apache.org/jira/browse/HBASE-11492?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Nicolas Liochon reassigned HBASE-11492:
---------------------------------------
Assignee: Nicolas Liochon
> The servers do not honnor the tcpNoDelay option
> -----------------------------------------------
>
> Key: HBASE-11492
> URL: https://issues.apache.org/jira/browse/HBASE-11492
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.98.0, 0.96.0, 0.99.0
> Reporter: Nicolas Liochon
> Assignee: Nicolas Liochon
> Priority: Critical
> Fix For: 0.99.0, 0.98.5
>
>
> There is an option to set tcpNoDelay, defaulted to true, but the socket channel is actually not changed. As a consequence, the server works with nagle enabled. This leads to very degraded behavior when a single connection is shared between threads. We enter into conflicts with nagle and tcp delayed ack.
> Here is an example of performance with the PE tool plus HBASE-11491:
> {noformat}
> oneCon #client sleep exeTime (seconds) avg latency, sleep excluded (microseconds)
> true 1 0 31 310
> false 1 0 31 310
> true 2 0 50 500
> false 2 0 31 310
> true 2 5 488 (including 200s sleeping) 2880
> false 2 5 246 (including 200s sleeping) 460
> {noformat}
> The latency is divided by 5 when the connection is shared. This is the delayed ack kicking in. This can be fixed by really using tcp no delay.
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