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https://issues.apache.org/jira/browse/CASSANDRA-10855?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15240837#comment-15240837
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Benedict edited comment on CASSANDRA-10855 at 4/14/16 9:12 AM:
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We should definitely address Branimir's
[comment|https://issues.apache.org/jira/browse/CASSANDRA-11452?focusedCommentId=15240789&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15240789]
before merging. As he says, this could theoretically completely eliminate the
benefit of the cache in certain circumstances.
I think both supporting larger hashes, and not comparing _only_ against the
main eviction candidate for admission (e.g. comparing against a value with
logarithmically random distance from the eviction candidate), are reasonably
easy and should solve the problem
was (Author: benedict):
We should definitely address Branimir's
[comment|https://issues.apache.org/jira/browse/CASSANDRA-11452?focusedCommentId=15240789&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15240789]
before merging. As he says, this could theoretically completely eliminate the
benefit of the cache in certain circumstances.
I think both supporting larger hashes, and not comparing _only_ against the
main eviction candidate for admission, are reasonably easy and should solve the
problem.
> 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
>
> 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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