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From "Robert Stupp (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-9754) Make index info heap friendly for large CQL partitions
Date Thu, 09 Jul 2015 06:20:05 GMT


Robert Stupp commented on CASSANDRA-9754:

Yes, the purpose of CASSANDRA-9738 is to move the (permanent part of the) key-cache to off-heap
- basically eliminating a huge amount of tiny object in the old gen.

bq. we can still optimize on reducing the objects created

Absolutely agree! Although, the first benchmark I did with CASSANDRA-9738 shows a huge reduction
of GC effort of roughly 90% (total and avg GC time with 8u45+G1) for a read-only workload
with actually more (short-lived) objects created - I suppose these will never be promoted
to the old gen.

> Make index info heap friendly for large CQL partitions
> ------------------------------------------------------
>                 Key: CASSANDRA-9754
>                 URL:
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: sankalp kohli
>            Priority: Minor
>  Looking at a heap dump of 2.0 cluster, I found that majority of the objects are IndexInfo
and its ByteBuffers. This is specially bad in endpoints with large CQL partitions. If a CQL
partition is say 6,4GB, it will have 100K IndexInfo objects and 200K ByteBuffers. This will
create a lot of churn for GC. Can this be improved by not creating so many objects?

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