[9.2] Avoid rewrite round_to with expensive queries (#135987)#135992
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elasticsearchmachine merged 1 commit intoelastic:9.2from Oct 4, 2025
Merged
[9.2] Avoid rewrite round_to with expensive queries (#135987)#135992elasticsearchmachine merged 1 commit intoelastic:9.2from
elasticsearchmachine merged 1 commit intoelastic:9.2from
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Today, we use a threshold (defaults to 128) to avoid generating too many sub-queries when replacing round_to with sub-queries. However, we do not account for cases where the main query is expensive. In such cases, running many expensive queries is slower and more costly than running a single query and then reading values and rounding. Our benchmark shows that this query takes 800ms with query-and-tags, but only 40ms without it. TS metric* | WHERE host.name LIKE \"host-*\" AND @timestamp >= \"2025-07-25T12:55:59.000Z\" AND @timestamp <= \"2025-07-25T17:25:59.000Z\" | STATS AVG(AVG_OVER_TIME(`metrics.system.cpu.load_average.1m`)) BY host.name, TBUCKET(5 minutes) And this query: TS new_metrics* | WHERE host.name IN("host-0", "host-1", "host-2") AND @timestamp >= "2025-07-25T12:55:59.000Z" AND @timestamp <= "2025-07-25T17:25:59.000Z" | STATS AVG(AVG_OVER_TIME(`metrics.system.cpu.load_average.1m`)) BY host.name, TBUCKET(5 minutes) reduces from 50ms to 10ms. This change proposes using the threshold as the number of query clauses and assigning higher weights to expensive queries, such as wildcard or prefix queries. This allows us to disable the rewrite when it is less efficient, while still enabling it if the number of sub-queries is small.
dnhatn
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:Analytics/ES|QL
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Backports the following commits to 9.2: