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From "Robert Stupp (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-10855) Use Caffeine (W-TinyLFU) for on-heap caches
Date Wed, 06 Jan 2016 20:50:39 GMT


Robert Stupp commented on CASSANDRA-10855:

It would help if we would have some more workloads as cassandra-stress profiles. Could you
help with that?

BTW, I have to correct my last statement partly: _trades-fwd-lcs-nolz4_ has the 99.x% key-cache
hit ration (using 10% of the key cache's capacity) and, _regression r/w_ has the bad, ~10%
hit ratio. (Sorry for the confusion, I accidentally swapped the console log files to get the
hit ratios)

_trades-fwd-lcs-nolz4_ [Operation 1|]
(mixed writes+reads) gives a nice perf improvement during the first seconds but then egalizes
with the existing implementation. [Operation 2|],
4 and 6 (all just reads) show a slight regression or no difference.
OTOH _cassci regression test r/w_ shows the perf regression of about 5%.

> Use Caffeine (W-TinyLFU) for on-heap caches
> -------------------------------------------
>                 Key: CASSANDRA-10855
>                 URL:
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Ben Manes
>              Labels: performance
> Cassandra currently uses [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 All of these usages have been replaced by [Caffeine|],
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|] 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|]
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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