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https://issues.apache.org/jira/browse/CASSANDRA-5661?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13733830#comment-13733830
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Ben Manes commented on CASSANDRA-5661:
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My benchmark had a bug and EBS may only be on par with LTQ performance wise. I
need to investigate that again, though.
I shifted focus to fixing the performance bottleneck in Guava's cache. The way
we tracked usage history (e.g. LRU) was focused on common usage, but is a
bottleneck on synthetic benchmarks. I made the fixes to CLHM (v1.4) and offered
them upstream (issue 1487). I'll experiment with using CLHM instead to see if
that removes the hotspot.
> Discard pooled readers for cold data
> ------------------------------------
>
> Key: CASSANDRA-5661
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5661
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 1.2.1
> Reporter: Jonathan Ellis
> Assignee: Pavel Yaskevich
> Fix For: 2.0.1
>
> Attachments: CASSANDRA-5661-global-multiway-cache.patch,
> CASSANDRA-5661.patch, DominatorTree.png, Histogram.png
>
>
> Reader pooling was introduced in CASSANDRA-4942 but pooled
> RandomAccessReaders are never cleaned up until the SSTableReader is closed.
> So memory use is "the worst case simultaneous RAR we had open for this file,
> forever."
> We should introduce a global limit on how much memory to use for RAR, and
> evict old ones.
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