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https://issues.apache.org/jira/browse/CASSANDRA-5661?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13701544#comment-13701544
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Ben Manes commented on CASSANDRA-5661:
--------------------------------------
I solved the LRU problem years ago, which gave you CLHM and Guava's Cache. It
scales very well without degrading due to LRU management under higher thread
count, limited primarily by the hash table usage. Previous approaches didn't
scale to 4-8 threads, but 32+ is limited by the chosen hash table design.
In neither approaches will there be significant contention or overhead. The
difference is about the level of granularity to bound the resources by and how
to evict them.
You seem to be focusing on tuning parameters, minute details, etc. for a class
written in a few evenings as a favor, knowing that those things are trivial to
change. There's not much of a point debating it with me as I don't care and
have no stake or interest in what is decided. Especially when you're comparing
it against a simplistic usage relying on another class I wrote much of,
Guava's. In the end something I wrote will be used to solve this bug. ;)
> 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: 1.2.7
>
> Attachments: 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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