[CASSANDRA-15392] Pool Merge Iterators

• Type: Sub-task
• Status: Resolved
• Priority: Normal
• Resolution: Won't Fix
• Fix Version/s: 4.0.1
• Component/s: Local/Compaction
• Change Category: Performance
• Complexity: Normal
• Platform: All

Test and Documentation Plan

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• Assignee: Blake Eggleston
• Reporter: Blake Eggleston

Authors

Blake Eggleston

Reviewers

Benedict Elliott Smith, Jordan West

• Created: 30/Oct/19 22:36
• Updated: 01/Aug/21 11:33
• Resolved: 06/Oct/20 22:58

Description

By pooling merge iterators, instead of creating new ones each time we need them, we can reduce garbage on the compaction and read paths under relevant workloads by ~4% in many cases.

Issue Links

• is depended upon by: CASSANDRA-15533 Don't allocate unneeded MergeIterator in OnDiskToken#iterator