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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. -- This message was sent by Atlassian JIRA (v6.3.4#6332)