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https://issues.apache.org/jira/browse/CASSANDRA-2252?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13002414#comment-13002414
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Stu Hood commented on CASSANDRA-2252:
-------------------------------------
I'd like to go ahead and merge these patches together onto jbellis's version.
Things that I will cherry pick from the alternate patch:
* A generic Allocator interface, rather than referring to Memtables. There are
various other places that we need to apply slabbing
* The additional counter tests we added
* Using the slab allocator's allocation count to determine throughput for
memtables
----
The other realization we've had about slab allocation is that unless _all_
sources of fragmentation are eliminated, slabbing actually causes promotion
failures to happen earlier, since it is harder to promote a slab into a
fragmented oldgen. The other sources of fragmentation we suspect are:
* IndexSummaries (easily slabbed)
* the key and row caches (row cache tackled in CASSANDRA-1969)
These can probably be defragged in separate tickets, as long as we commit to
fixing them.
> off-heap memtables
> ------------------
>
> Key: CASSANDRA-2252
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2252
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Jonathan Ellis
> Assignee: Jonathan Ellis
> Fix For: 0.8
>
> Attachments: 0001-add-MemtableAllocator.txt,
> 0002-add-off-heap-MemtableAllocator-support.txt, 2252-alternate-v2.tgz
>
>
> The memtable design practically actively fights Java's GC design. Todd
> Lipcon gave a good explanation over on HBASE-3455.
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