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https://issues.apache.org/jira/browse/ACCUMULO-4177?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15275491#comment-15275491
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Ben Manes commented on ACCUMULO-4177:
-------------------------------------
[Druid|http://druid.io/] was recently struck by [JDK-8078490 - Missed
submissions in ForkJoinPool|https://bugs.openjdk.java.net/browse/JDK-8078490].
This caused the cache to stop evicting because the asynchronous task was never
run due to a race in the executor. The result was either a memory leak (2.2.6)
or halting due to the back pressure (2.3.0). The solution if you are running on
an older JDK8 release is to use a different executor (e.g. same-thread). This
critical bug effected 8u40 - 8u60 (current is 8u92) and broke any FJP usage,
such as *CompletableFuture*. I confirmed this fix with Doug Lea when
investigating.
In other news, Cassandra recently adopted Caffeine for its [page
cache](https://issues.apache.org/jira/browse/CASSANDRA-5863). Their analysis of
the performance, hit rate, and scan tolerance were positive. I'm hoping to
integrate the eviction policy into their off-heap cache
([OHC|https://github.com/snazy/ohc]), which uses LRU. That cache is extracted
into a library so contributing there might make it easy for you to benefit as
well.
> TinyLFU-based BlockCache
> ------------------------
>
> Key: ACCUMULO-4177
> URL: https://issues.apache.org/jira/browse/ACCUMULO-4177
> Project: Accumulo
> Issue Type: Improvement
> Reporter: Ben Manes
> Fix For: 2.0.0
>
> Attachments: ACCUMULO-4177.patch
>
>
> [LruBlockCache|https://github.com/apache/accumulo/blob/master/core/src/main/java/org/apache/accumulo/core/file/blockfile/cache/LruBlockCache.java]
> appears to be based on HBase's. I currently have a patch being reviewed in
> [HBASE-15560|https://issues.apache.org/jira/browse/HBASE-15560] that replaces
> the pseudo Segmented LRU with the TinyLFU eviction policy. That should allow
> the cache to make [better
> predictions|https://github.com/ben-manes/caffeine/wiki/Efficiency] based on
> frequency and recency, such as improved scan resistance. The implementation
> uses [Caffeine|https://github.com/ben-manes/caffeine], the successor to
> Guava's cache, to provide concurrency and keep the patch small.
> Full details are in the JIRA ticket. I think it should be easy to port if
> there is interest.
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