[CASSANDRA-6953] Optimise CounterCell#reconcile

• Type: Improvement
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 2.1 beta2
• Assignee: Aleksey Yeschenko
• Reporter: Aleksey Yeschenko

Authors

Aleksey Yeschenko

Reviewers

Sylvain Lebresne

• Created: 30/Mar/14 03:02
• Updated: 16/Apr/19 09:31
• Resolved: 31/Mar/14 10:28

Description

Can't have CASSANDRA-6506 in 2.1, but we can get some of the benefit by optimising CounterCell#reconcile() as it is.

Specifically, if one context is a superset of the other one, there is no need to allocate a BB for the resulting context and merge them - we can just return the superset context. With 2.1 producing global shards exclusively, this would minimize allocations by a lot for reads from multiple sstables.