[CASSANDRA-7882] Memtable slab allocation should scale logarithmically to improve occupancy rate

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.1.3
• Labels: performance
• Assignee: Benedict Elliott Smith
• Reporter: Jay Patel

Authors

Benedict Elliott Smith

Reviewers

Jay Patel

• Tester: Benedict Elliott Smith
• Created: 05/Sep/14 08:13
• Updated: 16/Apr/19 09:31
• Resolved: 12/Dec/14 14:20

Description

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.