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https://issues.apache.org/jira/browse/CASSANDRA-13090?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15805011#comment-15805011
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Ariel Weisberg commented on CASSANDRA-13090:
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* I don't think {{otc_coalescing_max_coalesced_messages}} is useful although
I'm interested in hearing the argument for it. When is pulling more than 128
items out of the LBQ going to improve performance?
* I think rather for the growing backlog scenario we should skip coalescing
entirely and rely on back pressure from the socket to block the thread. So
right now if coalescing says "write stuff" we should skip coalescing until the
backlog has been drained into the socket. The strategy will need to know about
the messages so it can log the arrival rate.
* Granted since the batch size is 128 it will still only add the undesired
coalescing every 128 messages and only if the backlog is <
{{otc_coaslescing_enough_coalesced_messages}}
* {{otc_coaslescing_enough_coalesced_messages}} in the yaml has a typo
* {{otc_coalescing_window_us}} has a typo in the comment
* Is there an extra drain to in {{coalesceInternal}}? One in the condition and
another immediately after before checking for enough?
> Coalescing strategy sleep too much
> ----------------------------------
>
> Key: CASSANDRA-13090
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13090
> Project: Cassandra
> Issue Type: Bug
> Components: Streaming and Messaging
> Reporter: Corentin Chary
> Fix For: 3.x
>
> Attachments: 0001-Fix-wait-time-coalescing-CASSANDRA-13090.patch
>
>
> With the current code maybeSleep is called even if we managed to take
> maxItems out of the backlog. In this case we should really avoid sleeping
> because it means that backlog is building up.
> I'll send a patch shortly.
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