Fix segment-specific TermInSetQuery rewrites thrashing caching policy #15441
+80
−4
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
Fixes #14986.
A
TermInSetQuerywithrewriteMethod = MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITEcreates aRewritingWeight. Getting a scorer from thisRewritingWeightfor a segment could involve rewriting to aBooleanQueryof multipleTermQuerywith only the terms present in that particular segment.These segment-specific
BooleanQueryrewrites all thrash theUsageTrackingQueryCachingPolicyring buffer, which is shared across all segments of the index. The expectation is that we mark a query only once per shard in this ring buffer - refIn this change: When initializing
AbstractMultiTermQueryConstantScoreWrapper.RewritingWeight, we copy the supplied indexSearcher but withsetQueryCache(null)and pass it along for the segment-specific rewrites. The subsequent rewrites into BooleanQuery of TermQuery don't go through the query cache (The idea is that these should be cached as the parent TermInSet query itself)