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https://issues.apache.org/jira/browse/CASSANDRA-9558?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14593780#comment-14593780
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Norman Maurer commented on CASSANDRA-9558:
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Sorry for been late to the party, but it somehow got lost in my inbox :(
So from a netty standpoint your are right flushing from outside the EventLoop
is "pretty expensive" as it will need to wakeup the selector if it is not
already woken up and processing stuff.
So the best thing you can do is either always write / flush etc from within the
EventLoop or try to minimize the flushes from outside the EventLoop. That said
if you point me to the place in your code where you do the flush and the other
stuff I'm happy to have a look and see if I can give you some idea how to
improve.
Just let me know!
> Cassandra-stress regression in 2.2
> ----------------------------------
>
> Key: CASSANDRA-9558
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9558
> Project: Cassandra
> Issue Type: Bug
> Reporter: Alan Boudreault
> Fix For: 2.2.0 rc2
>
> Attachments: 2.1.log, 2.2.log, CASSANDRA-9558-2.patch,
> CASSANDRA-9558-ProtocolV2.patch, atolber-CASSANDRA-9558-stress.tgz,
> atolber-trunk-driver-coalescing-disabled.txt,
> stress-2.1-java-driver-2.0.9.2.log, stress-2.1-java-driver-2.2+PATCH.log,
> stress-2.1-java-driver-2.2.log, stress-2.2-java-driver-2.2+PATCH.log,
> stress-2.2-java-driver-2.2.log
>
>
> We are seeing some regression in performance when using cassandra-stress 2.2.
> You can see the difference at this url:
> http://riptano.github.io/cassandra_performance/graph_v5/graph.html?stats=stress_regression.json&metric=op_rate&operation=1_write&smoothing=1&show_aggregates=true&xmin=0&xmax=108.57&ymin=0&ymax=168147.1
> The cassandra version of the cluster doesn't seem to have any impact.
> //cc [~tjake] [~benedict]
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