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Ariel Weisberg commented on CASSANDRA-9318:
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I am not sure how they have structured things and why they need to do that.
With a hard limit on ingest rate and a 2 second timeout there is a soft bound
on how much memory can be committed. It's not a hard bound because there is no
guarantee that the timeout thread will keep up.
I do think that switching requests from async to sync based on load is a better
approach than enabling/disabling read on client connections. There can be a lot
of client connections so that is something that can be time consuming.
I am not sold that we should do anything at all? We could add more code to
address this, but I hate to do that when I can't demonstrate that I am solving
a problem. I split off what I consider the good bits into CASSANDRA-10971 and
CASSANDRA-10972. The delay has been other work, me considering this to be
lowish priority since I can't demonstrate it, and difficulty getting hardware
going that is capable of demonstrating the problem. I'm slowly iterating on it
in the background right now.
> 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: Ariel Weisberg
> Fix For: 2.1.x, 2.2.x
>
>
> 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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