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Robert Stupp commented on CASSANDRA-7438: ----------------------------------------- bq. I don't think we changed the format, did i? Ah - no. Sorry - got confused with the in-memory serialization. bq. item.refcount What I mean is the the (Intel) CPU L1+L2 cache line size (64 bytes). If 'refcount' is updated (e.g. just for a cache-get), the whole cache line is invalidated (twice) and needs to be re-fetched from RAM although its content did not change. It's just a point for optimization - if we find a viable solution for that, we should implement it. > 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 > > > 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. -- This message was sent by Atlassian JIRA (v6.3.4#6332)