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https://issues.apache.org/jira/browse/CASSANDRA-5661?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13707689#comment-13707689
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Ben Manes commented on CASSANDRA-5661:
--------------------------------------
LTQ is best when you allow there to be some spin between producers and
consumers, as its optimized for message passing scenarios. In your usage you
don't allow any delay, so the likelihood of a successful transfer is low. When
transfers are common, the overhead is less due to fewer contented CAS
operations.
If desired, I can make the pool parameterized to take a supplier of queues to
produce so you can parameterize that as well.
The pool will always be slower than the FileCacheService patch, since it does
more. The decision is whether the performance degradation is acceptable and if
the rational for the pool is to provide a finer grained eviction policy is
still desired.
> 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
>
> Attachments: CASSANDRA-5661-multiway-per-sstable.patch,
> CASSANDRA-5661.patch, CASSANDRA-5661-v2-global-multiway-per-sstable.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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