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Add hook for LRUQueryCache to allow custom population strategies - #15723
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dnhatn
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February 19, 2026 01:05
romseygeek
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Feb 19, 2026
| assertThat(reader.leaves(), hasSize(1)); | ||
| LeafReaderContext singleLeaf = reader.leaves().get(0); | ||
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| AtomicInteger visited = new AtomicInteger(0); |
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It took me a while to work out what this test was actually doing (dividing up the document space into numThreads sections, and searching each section separately in its own thread) - maybe add some comments to make it a bit clearer?
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@martijnvg @romseygeek Thank you! |
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) In Elasticsearch, we execute intra-segment searches across multiple threads, which can trigger redundant, concurrent cache populations for the same segment. Since each slice-search targets a subset of the segment but cache population scans the entire segment, this amplification significantly wastes I/O and CPU for expensive queries. This PR introduces a hook in LRUQueryCache to allow custom population strategies, such as delegating to a background thread or skipping redundant populations. There is no change to the default behavior of LRUQueryCache.
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In Elasticsearch, we execute intra-segment searches across multiple threads, which can trigger redundant, concurrent cache populations for the same segment. Since each slice-search targets a subset of the segment but cache population scans the entire segment, this amplification significantly wastes I/O and CPU for expensive queries. This PR introduces a hook in LRUQueryCache to allow custom population strategies, such as delegating to a background thread or skipping redundant populations. There is no change to the default behavior of LRUQueryCache. Backport of #15723 to 10.x
gmarouli
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…che#15723) In Elasticsearch, we execute intra-segment searches across multiple threads, which can trigger redundant, concurrent cache populations for the same segment. Since each slice-search targets a subset of the segment but cache population scans the entire segment, this amplification significantly wastes I/O and CPU for expensive queries. This PR introduces a hook in LRUQueryCache to allow custom population strategies, such as delegating to a background thread or skipping redundant populations. There is no change to the default behavior of LRUQueryCache.
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This change forks LRUQueryCache to include apache/lucene#15723 so that we can override cache population behavior for intra-segment searches. With ES|QL doc_partitioning, each thread can independently populates the query cache for the same segment. The actual changes will be in a follow-up PR. Once Lucene 10.5 or 11 is released, we should remove this fork.
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This change forks LRUQueryCache to include apache/lucene#15723 so that we can override cache population behavior for intra-segment searches. With ES|QL doc_partitioning, each thread can independently populates the query cache for the same segment. The actual changes will be in a follow-up PR. Once Lucene 10.5 or 11 is released, we should remove this fork.
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The fork existed only to backport apache/lucene#15723 (the tryPopulateCache hook for intra-segment cache population). Lucene 10.5 ships that hook, so ElasticsearchLRUQueryCache extends the upstream LRUQueryCache directly and the fork is deleted.
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Adds coverage for the intra-segment cache gate doc-partitioning relies on: a query whose weight is an OptionalCachingWeight populates the cache only when startCaching grants the claim, and falls back to an uncached scorer otherwise. Guards the seam now served by Lucene 10.5 (apache/lucene#15723).
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In Elasticsearch, we execute intra-segment searches across multiple threads, which can trigger redundant, concurrent cache populations for the same segment. Since each slice-search targets a subset of the segment but cache population scans the entire segment, this amplification significantly wastes I/O and CPU for expensive queries. This PR introduces a hook in LRUQueryCache to allow custom population strategies, such as delegating to a background thread or skipping redundant populations. There is no change to the default behavior of LRUQueryCache.