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https://issues.apache.org/jira/browse/CASSANDRA-7882?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14122602#comment-14122602
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Jay Patel edited comment on CASSANDRA-7882 at 9/5/14 8:16 AM:
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I've added code for this in my local env, and done some testing. Reduction in
allocated memory is significant with higher number of tables (1000s to 10s of
thousands) in a cluster. By default region-based allocation should be always-on
but providing this option will allow flexibility for packing more tables.
I'm fine if we should keep it undocumented like CASSANDRA-5935.
was (Author: pateljay3001):
I've added code for this in my loca env, and done some testing. Reduction in
allocated memory is significant with higher number of tables (1000s to 10s of
thousands) in a cluster. By default region-based allocation should be always-on
but providing this option will allow flexibility for packing more tables.
I'm fine if we should keep it undocumented like CASSANDRA-5935.
> Allow disabling slab allocation for off-heap memtables
> ------------------------------------------------------
>
> Key: CASSANDRA-7882
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7882
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Jay Patel
> Fix For: 2.1.1
>
>
> CASSANDRA-5935 allows option to disable region-based allocation for on-heap
> memtables but there is no option to disable it for off-heap memtables
> (memtable_allocation_type: offheap_objects).
> Disabling region-based allocation will allow us to pack more tables in the
> schema since minimum of 1MB region won't be allocated per table. Downside can
> be more fragmentation which should be controllable by using better allocator
> like JEMalloc.
> How about below option in yaml?:
> memtable_allocation_type: unslabbed_offheap_objects
> Thanks.
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