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https://issues.apache.org/jira/browse/CASSANDRA-10855?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15568161#comment-15568161
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Robert Stupp commented on CASSANDRA-10855:
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Haven't looked thoroughly through the code yet. One question: 
{{lib/caffeine-2.3.3.jar}} has been changed in the patch. Is it a new version 
of caffeine?

> Use Caffeine (W-TinyLFU) for on-heap caches
> -------------------------------------------
>
>                 Key: CASSANDRA-10855
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10855
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Ben Manes
>              Labels: performance
>         Attachments: CASSANDRA-10855.patch
>
>
> Cassandra currently uses 
> [ConcurrentLinkedHashMap|https://code.google.com/p/concurrentlinkedhashmap] 
> for performance critical caches (key, counter) and Guava's cache for 
> non-critical (auth, metrics, security). All of these usages have been 
> replaced by [Caffeine|https://github.com/ben-manes/caffeine], written by the 
> author of the previously mentioned libraries.
> The primary incentive is to switch from LRU policy to W-TinyLFU, which 
> provides [near optimal|https://github.com/ben-manes/caffeine/wiki/Efficiency] 
> hit rates. It performs particularly well in database and search traces, is 
> scan resistant, and as adds a very small time/space overhead to LRU.
> Secondarily, Guava's caches never obtained similar 
> [performance|https://github.com/ben-manes/caffeine/wiki/Benchmarks] to CLHM 
> due to some optimizations not being ported over. This change results in 
> faster reads and not creating garbage as a side-effect.



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