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https://issues.apache.org/jira/browse/CASSANDRA-7438?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14228569#comment-14228569
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Vijay commented on CASSANDRA-7438:
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{quote}The queue is maintained by a separate thread that requires
signalling{quote}
Thread is only signalled if they are not performing operation. I am lost.
{quote}resulting in a memory leak{quote}
I am 100% sure that this is not true. Can you write a test case for it to make
this happen plz?
{quote}but prevent all reader or writer threads from making progress by taking
the locks for all buckets immediately{quote}
I am sure this cannot be done, if you don't write you loose coherence and
consistency.
{quote}During a grow, we can lose puts because we unlock the old segments{quote}
test case again plz. I don't think this can happen too. I spend a lot of time
testing the exact scenario.
> Serializing Row cache alternative (Fully off heap)
> --------------------------------------------------
>
> Key: CASSANDRA-7438
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7438
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Environment: Linux
> Reporter: Vijay
> Assignee: Vijay
> Labels: performance
> Fix For: 3.0
>
> Attachments: 0001-CASSANDRA-7438.patch, tests.zip
>
>
> Currently SerializingCache is partially off heap, keys are still stored in
> JVM heap as BB,
> * There is a higher GC costs for a reasonably big cache.
> * Some users have used the row cache efficiently in production for better
> results, but this requires careful tunning.
> * Overhead in Memory for the cache entries are relatively high.
> So the proposal for this ticket is to move the LRU cache logic completely off
> heap and use JNI to interact with cache. We might want to ensure that the new
> implementation match the existing API's (ICache), and the implementation
> needs to have safe memory access, low overhead in memory and less memcpy's
> (As much as possible).
> We might also want to make this cache configurable.
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