[CASSANDRA-19191] Optimisations to PlacementForRange, improve lookup on r/w path

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 5.1-alpha1
• Component/s: Transactional Cluster Metadata
• Epic Link: CEP-21: Follow Up
• Change Category: Performance
• Complexity: Normal
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/34d999c47a4da6d43a67910354fb9888184b23ab

Test and Documentation Plan

ci run, existing tests

• Assignee: Marcus Eriksson
• Reporter: Marcus Eriksson

Authors

Marcus Eriksson

Reviewers

Alex Petrov, Sam Tunnicliffe

• Created: 11/Dec/23 13:57
• Updated: 20/May/24 11:31
• Resolved: 23/Apr/24 08:05

Description

The lookup used when selecting the appropriate replica group for a range or token while peforming reads and writes is extremely simplistic and inefficient. There is plenty of scope to improve PlacementsForRange to by replacing the current naive iteration with use a more efficient lookup.

Issue Links

• links to: GitHub Pull Request #3198