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https://issues.apache.org/jira/browse/CASSANDRA-9318?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15402137#comment-15402137
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Sergio Bossa commented on CASSANDRA-9318:
-----------------------------------------
Patch rebased to trunk, new links:
| [trunk
patch|https://github.com/apache/cassandra/compare/trunk...sbtourist:CASSANDRA-9318-trunk?expand=1]
|
[testall|https://cassci.datastax.com/view/Dev/view/sbtourist/job/sbtourist-CASSANDRA-9318-trunk-testall/]
|
[dtest|https://cassci.datastax.com/view/Dev/view/sbtourist/job/sbtourist-CASSANDRA-9318-trunk-dtest/]
| [dtest (back-pressure
enabled)|https://cassci.datastax.com/view/Dev/view/sbtourist/job/sbtourist-CASSANDRA-9318-bp-true-trunk-dtest/]
|
[~Stefania],
feel free to have another quick look at the new patch (no relevant changes by
the way).
[~eduard.tudenhoefner],
in terms of testing, I've already done some on my own as reported in one of my
earlier comments, but I am sure you'll have more to add; the objective of our
testing should be:
1) Verify there's no performance impact *at all* when back-pressure is disabled.
2) Verify there's no relevant performance impact when back-pressure is enabled
and the cluster is well-behaving.
3) Verify back-pressure works correctly when the cluster is overloaded, and
dropped mutations are reduced (how much reduced, it depends on the actual
back-pressure configuration, and I hope the {{cassandra.yaml}} comments will
help with that, otherwise let me know what's unclear and I'll improve them).
All tests should be run with at least 4 nodes and RF=3, the attached ByteMan
rule can be used to simulate "slow replica" scenarios and kick-in back-pressure.
> Bound the number of in-flight requests at the coordinator
> ---------------------------------------------------------
>
> Key: CASSANDRA-9318
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9318
> Project: Cassandra
> Issue Type: Improvement
> Components: Local Write-Read Paths, Streaming and Messaging
> Reporter: Ariel Weisberg
> Assignee: Sergio Bossa
> Attachments: 9318-3.0-nits-trailing-spaces.patch, backpressure.png,
> limit.btm, no_backpressure.png
>
>
> It's possible to somewhat bound the amount of load accepted into the cluster
> by bounding the number of in-flight requests and request bytes.
> An implementation might do something like track the number of outstanding
> bytes and requests and if it reaches a high watermark disable read on client
> connections until it goes back below some low watermark.
> Need to make sure that disabling read on the client connection won't
> introduce other issues.
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