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Date: Thu, 19 Feb 2015 19:48:13 +0000 (UTC)
From: "Benedict (JIRA)" <jira@apache.org>
To: commits@cassandra.apache.org
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Subject: [jira] [Commented] (CASSANDRA-8692) Coalesce intra-cluster network
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    [ https://issues.apache.org/jira/browse/CASSANDRA-8692?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14328016#comment-14328016 ] 

Benedict commented on CASSANDRA-8692:
-------------------------------------

There are some unnecessary changes we could split out to only hit trunk (such as optional NODELAY), but there has to be at least a minimal touching of the existing code. As it stands the most egregious such touch is the switch from currentTimeMillis() to nanoTime() with a conversion that we perform back to millis for serialization. It's unavoidable to at least call nanoTime(), but we could perhaps call both instead, but that may have a material performance impact (esp. on virtualized setups with a poor choice of clocksource)

Other than that, there is a switch of buffer size that is deferrable but safe, and the movement of a small portion of code into an abstract "DisabledStrategy" class from OTC, which is also very easily verifiable. We can even make it an almost identical cut/paste, but that's probably unnecessary.

> Coalesce intra-cluster network messages
> ---------------------------------------
>
>                 Key: CASSANDRA-8692
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8692
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Ariel Weisberg
>            Assignee: Ariel Weisberg
>             Fix For: 2.1.4
>
>         Attachments: batching-benchmark.png
>
>
> While researching CASSANDRA-8457 we found that it is effective and can be done without introducing additional latency at low concurrency/throughput.
> The patch from that was used and found to be useful in a real life scenario so I propose we implement this in 2.1 in addition to 3.0.
> The change set is a single file and is small enough to be reviewable.


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