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https://issues.apache.org/jira/browse/CASSANDRA-19679?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17852462#comment-17852462
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Benjamin Lerer commented on CASSANDRA-19679:
--------------------------------------------

Looking at the allocation. It seems that {{MultiCBuilder}} is creating some 
iterators when it should not have. We should probably try to replace the 
for-each loops by some normal index loop and see how things changes.

> Stream processing for SimpleRestriction::bindAndGetClusteringElements
> ---------------------------------------------------------------------
>
>                 Key: CASSANDRA-19679
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-19679
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Legacy/Core
>            Reporter: Sam Lightfoot
>            Assignee: Sam Lightfoot
>            Priority: Normal
>             Fix For: 5.x
>
>         Attachments: after.png, alloc_after.html, alloc_before.html, 
> image-2024-06-04-21-55-34-457.png
>
>          Time Spent: 3h 10m
>  Remaining Estimate: 0h
>
> Part 2 (of 2) of low-hanging fruit Stream performance improvements.
> The second main Stream contributor to allocations and CPU was 
> SimpleRestriction::bindAndGetClusteringElements, which contributes to 5% of 
> all allocations for a 50/50 workload. The image attached shows allocation 
> profiling on _trunk_ (see purple highlighted sections for Stream-related 
> allocs).
> The 'after' profile for a 50/50 workload shows a reduction from 4.58% 
> allocations down to 1.69%. For a 90/10 (w/r) workload we see 4.28% decrease 
> to 1.10%.



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