[jira] [Updated] (CASSANDRA-10971) Compressed commit log has no backpressure and can OOM

["Ariel Weisberg (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-10971?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ariel Weisberg updated CASSANDRA-10971:
---------------------------------------
    Status: Patch Available  (was: In Progress)

Turns out I did need to poke the CLSM thread, but it's not a big deal to pass in a handle for poking it.

> Compressed commit log has no backpressure and can OOM
> -----------------------------------------------------
>
>                 Key: CASSANDRA-10971
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10971
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Local Write-Read Paths
>            Reporter: Ariel Weisberg
>            Assignee: Ariel Weisberg
>             Fix For: 3.0.x, 3.x
>
>
> I validated this via a unit test that slowed the ability of the log to drain to the filesystem. The compressed commit log will keep allocating buffers pending compression until it OOMs.
> I have a fix that am not very happy with because the whole signal a thread to allocate a segment that depends on a resource that may not be available results in some obtuse usage of {{CompleatableFuture}} to rendezvous available buffers with {{CommitLogSegmentManager}} thread waiting to finish constructing a new segment. The {{CLSM}} thread is in turn signaled by the thread(s) that actually wants to write to the next segment, but aren't able to do it themselves.



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