Use the doc-values skip index to skip per-doc value lookups in LongRangeFacetCutter#16268
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slow-J wants to merge 5 commits into
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Use the doc-values skip index to skip per-doc value lookups in LongRangeFacetCutter#16268slow-J wants to merge 5 commits into
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I reran benchmarks, this time correctly using localrun, and updated the results in #16268 (comment) |
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epotyom
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Nice change! One suggestion below
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| /** Single-valued {@link LongValues} for {@link #skipField} in this segment. */ | ||
| final LongValues skipFieldValues(LeafReaderContext context) throws IOException { |
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Is this method a part of the single value unwrapping logic that we want to remove for now?
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Nope, this is part of the core skipper path.
…range-facets # Conflicts: # lucene/CHANGES.txt
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Resolves #16249
Implementation heavily inspired by HistogramCollector.java.
Range faceting (in the sandbox module -
LongRangeFacetCutter) currently reads the doc-values value for every matching document and binary-searches it into an elementary interval. When the faceted field is single-valued, we can use a doc-values skip index. For a dense skip block whose min and max values fall into the same elementary interval, every document in that block maps to that interval, allowing us to skip the per-doc value lookup and binary search.Limitation - applies to single-valued, long fields only.
Benchmark (luceneutil)
I used my branch of https://github.com/slow-J/luceneutil/tree/github-16249-range-facet-bench which cherry picked 2 of @epotyom 's commits (mainly mikemccand/luceneutil#582 which adds range-facet support)
Setup:
runlocal.py,wikimediumall(33.3M docs), index-sorted bylastMod_skipperwithaddDVSkippers=true. baseline = main, candidate = this change, both DURING_COLLECTION, sothe only difference is this optimization. 30 JVM iterations.
Command:
python3 -u src/python/localrun.py -s rangeFacetsWikimediumAll -b lucene_baseline -c lucene_candidate -iterations 30 -warmups 20 2>&1 | tee "$BASE/run-timing7.txt"Edit: new benchmark results after the changes for Egors first 2 comments.
Edit2: new benchmark results after unwrapping removed
QPS
Latency (ms) — aggregated across all iterations