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https://issues.apache.org/jira/browse/CASSANDRA-6809?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14103387#comment-14103387
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Jason Brown commented on CASSANDRA-6809:
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bq. It's also potentially less capable of utilising machines with... / won't
utilise all of our users' hardware maximally
Let's face it, if you're hitting the CL hard, you're also hitting the
memtables, et al, pretty hard, as well, due a consistently large number of
writes coming in. As long as the CL doesn't fall behind/take up too many
resources/does it's job and doesn't complain, I think that's the sweet spot.
I'd rather have the resources optimized for the client-facing path.
bq. dropping CLS recycling ... never really convinced it was worth the effort
I tend to agree with this. I'd like to think it's a nice win, but I have no
numbers to back it up. I think the pre-allocation is good (and a cheap
operation, at least by LOC), but the recycling I'm not sure of. [~rbranson],
it's been a few years since you implemented this in CASSANDRA-3411, how do feel
about it now, with several years of production experience?
bq. We'll want to limit the concurrency in this case
Does this statement apply to this ticket or CASSANDRA-7075? Seems more apropos
to the later.
> Compressed Commit Log
> ---------------------
>
> Key: CASSANDRA-6809
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6809
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Benedict
> Assignee: Branimir Lambov
> Priority: Minor
> Labels: performance
> Fix For: 3.0
>
>
> It seems an unnecessary oversight that we don't compress the commit log.
> Doing so should improve throughput, but some care will need to be taken to
> ensure we use as much of a segment as possible. I propose decoupling the
> writing of the records from the segments. Basically write into a (queue of)
> DirectByteBuffer, and have the sync thread compress, say, ~64K chunks every X
> MB written to the CL (where X is ordinarily CLS size), and then pack as many
> of the compressed chunks into a CLS as possible.
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