~/talk

Accelerating Aggregations with Lucene-Aware Execution in OpenSearch

Talkat OpenSearchCon Europe 2026 · on Thursday, 2026-04-16· at 15:50· Bohemia 2· [java, web-performance]
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slides:none on file

Claim: replacing per-document JVM-heavy collectors with Lucene bulk primitives plus OpenSearch batching reduces aggregation CPU overhead dramatically. Implementation uses Lucene collect doc ID stream and intoArray to fill a 256-int buffer, a long values fast path to load values, and skip-indexed 4k blocks with popcount; date-histogram cases see up to 20x speedups (filter-rewrite earlier gave 50x, multi-range 100x), storage cost ~0.1% for timestamp; works well for time-series, fails on unsorted or multi-valued fields.

AI-written summary · about

  1. 0:00Aggregation acceleration intro
  2. 1:23Slow aggregations problem
  3. 3:13Default execution flow
  4. 6:27Prior optimizations recap
  5. 8:53Lucene bulk APIs
  6. 14:34Batch collection design
  7. 21:16Skip indices integration
  8. 25:12Optimization limitations
  9. 26:38Automatic complementarity
  10. 27:22Future roadmap
  11. 32:48Key takeaways
  12. 34:53Resources and involvement
  13. 35:20Q&A
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