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https://issues.apache.org/jira/browse/CASSANDRA-9318?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15373750#comment-15373750
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Sergio Bossa commented on CASSANDRA-9318:
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[~jbellis],
bq. I think you just explained why that's not a very good reason to add more
complexity here, at least not without a demonstration that it's actually still
a problem.
Hints are not a solution for chronically overloaded clusters where clients
ingest faster than replicas can consume: even if hints get delivered timely and
reliably, replicas will always play catchup if there's no back-pressure. I find
this pretty straightforward, but as a practical example, try injecting the
attached byteman rule into a cluster and see it fall over at a rate of hundred
of thousand dropped mutations per minute.
bq. But CL is per request. How do you disentangle that client side?
Not sure I follow your objection, can you elaborate?
bq. And we're still not solving what I think is (post file-based hints) the
real problem, my scenario 3.
I think we do solve that, actually in a better way, which takes into
consideration all replicas, not just the coordinator capacity of acting as a
buffer, unless I'm missing a specific case you're referring to?
> 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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