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https://issues.apache.org/jira/browse/CASSANDRA-19986?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Berenguer Blasi updated CASSANDRA-19986:
----------------------------------------
    Change Category: Performance
         Complexity: Normal
        Component/s: Legacy/CQL
      Fix Version/s: 4.0.x
                     4.1.x
                     5.0.x
                     5.1
             Status: Open  (was: Triage Needed)

> Prepared statements cache computation improvements
> --------------------------------------------------
>
>                 Key: CASSANDRA-19986
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-19986
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Legacy/CQL
>            Reporter: Berenguer Blasi
>            Assignee: Berenguer Blasi
>            Priority: Normal
>             Fix For: 4.0.x, 4.1.x, 5.0.x, 5.1
>
>
> Currently prepared statements size are computed twice which is duplicate 
> effort:
> - 
> https://github.com/apache/cassandra/blob/cassandra-4.0/src/java/org/apache/cassandra/cql3/QueryProcessor.java#L672
> - 
> https://github.com/apache/cassandra/blob/cassandra-4.0/src/java/org/apache/cassandra/cql3/QueryProcessor.java#L802
> But we also get the side effect of that 'slow' computation locking the 
> underlying ConcurrentHashMap. We've had nodes becoming unresponsively slow 
> for hours with hundreds of threads in jstack all queued up behind 
> {{computeIbAbsent}} operations on cache insertion/eviction collisions.
> Computing size only once and pulling that value instead of recomputing it on 
> cache insertion was the solution



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