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https://issues.apache.org/jira/browse/CASSANDRA-11070?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15117032#comment-15117032
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Benedict commented on CASSANDRA-11070:
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I think you're confusing {{>}} with {{>=}}; this guard flushes if it's the
third flush in a row that produced work, or the second which did _not_ produce
work; i.e. it flushes if:
# there have been three batches appear together (each could be singleton items,
with arbitrary temporal separation)
# there has been one batch followed by a >10us pause
# there are more than fifty messages waiting
Your guard changes this to only 1 and 3.
> Dispatcher.Flusher's control has duplicated/conflict control
> ------------------------------------------------------------
>
> Key: CASSANDRA-11070
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11070
> Project: Cassandra
> Issue Type: Bug
> Components: Streaming and Messaging
> Reporter: fujian
> Labels: performance
> Attachments: 0001-fix-CASSANDRA-11070.patch
>
>
> org.apache.cassandra.transport.Message.Dispatcher.Flusher
> remove duplicated control for flush message control …
> Motivation:
> the !doneWork's control is duplicated and confused with runsSinceFlush > 2
> if on the first run:the queue size is 20
> donework will be set to true and not do flush due to the size<50 and
> runsSinceFlush<2.
> if on the second run. the queue size is 0,
> donework will be reset to false and not set to true due to no new items in
> queue, but the flush will be triggered due to:
> if (!doneWork || runsSinceFlush > 2 || flushed.size() > 50)
> now the runsSinceFlush is 2. so in actual, its function is similar with
> runsSinceFlush>1.
> so it is no need to keep it so that the code is confused and duplicated.
>
> Modifications:
> remove it
> Result:
> after remove it, it will more clear and no confused.
> check the link:
> https://github.com/jiafu1115/cassandra/commit/5279884e6a392d36b4adc5e29f9ca5d0666cb275
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