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https://issues.apache.org/jira/browse/HBASE-11492?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Misty Stanley-Jones updated HBASE-11492:
----------------------------------------
Release Note:
If the Hadoop configuration is read after the HBase configuration, Hadoop's
settings can override HBase's settings if the names of the settings are the
same. To avoid the risk of override, HBase has renamed the following settings
(by prepending 'hbase.') so that you can set them independent of your setting
for Hadoop. If you do not use the HBase-specific variants, the Hadoop settings
will be used.
Old Name New Name
==========================================================================
ipc.server.listen.queue.size hbase.ipc.server.listen.queue.size
ipc.server.max.callqueue.size hbase.ipc.server.max.callqueue.size
ipc.server.read.threadpool.size hbase.ipc.server.read.threadpool.size
ipc.server.tcpkeepalive hbase.ipc.server.tcpkeepalive
ipc.server.tcpnodelay hbase.ipc.server.tcpnodelay
ipc.client.call.purge.timeout hbase.ipc.client.call.purge.timeout
ipc.client.connection.maxidletime hbase.ipc.client.connection.maxidletime
ipc.client.idlethreshold hbase.ipc.client.idlethreshold
ipc.client.kill.max hbase.ipc.client.kill.max
> Hadoop configuration overrides some ipc parameters including tcpNoDelay
> -----------------------------------------------------------------------
>
> Key: HBASE-11492
> URL: https://issues.apache.org/jira/browse/HBASE-11492
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.98.0, 0.99.0
> Reporter: Nicolas Liochon
> Assignee: Nicolas Liochon
> Priority: Critical
> Fix For: 0.99.0, 0.98.4, 2.0.0
>
> Attachments: 11492.v1.patch, 11492.v1.withp1.patch,
> 11492.v2-0.98.patch, 11492.v2.patch, 11492.v2.patch
>
>
> 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 multiple by 5 (2880 vs 460) when the connection is shared.
> This is the delayed ack kicking in. This can be fixed by really using tcp no
> delay.
> Any application sharing the tcp connection between threads has the issue.
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