[LUCENE-10041] Duplication computation for TieredMergePolicy's numDeletesToMerge

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 8.4
• Component/s: core/index
• Lucene Fields: New
• Assignee: Nhat Nguyen
• Reporter: Feng Gui
• Created: 29/Jul/21 18:21
• Updated: 28/Aug/22 16:24

Description

In lucene 8.4 (Elasticsearch 7.6.2), all indices are enabled with soft-deletes. We found the TieredMergePolicy contains redundant query computation to acquire numDeletesToMerge for findMerges. According to code from getSortedBySegmentSize , I think we should reuse the result of numDeletesToMerge which can reduce 3% CPU and some IO overheads.

 
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Issue Links

• links to: GitHub Pull Request #231