Avoid an unintended FOR UPDATE query execution inside lock_candidates#720
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rosa merged 1 commit intorails:mainfrom Mar 2, 2026
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Without `#to_a`, `select_candidates` returns an `ActiveRecord::Relation`. Consequently, `executeions.none?` inside the `lock_candidates` method triggers an unintended query: ``` SELECT 1 AS one FROM `solid_queue_ready_executions` LIMIT 1 FOR UPDATE SKIP LOCKED; ```
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The SQLite test failed. I’ll look into it and try to fix it. |
Contributor
Author
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Is this failure a known issue? |
Member
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Yes, it's a flaky test, I need to fix it. Thanks for this, good catch! |
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With 408b84c,
select_candidatesbegan returning anActiveRecord::Relationinstead of anArray.Consequently, calling
executions.none?insidelock_candidatesnow triggers anSELECT 1 ... FOR UPDATE SKIP LOCKEDquery:While we are still investigating the exact database mechanics, this additional locking query has become a performance bottleneck in our environment. (We are currently conducting performance tests as part of migrating from another queue backend to Solid Queue).
Since this behavior change appears to be an unintended side effect, this PR adds
.to_ato ensure the relation is loaded as an array, avoiding the redundant query and improving performance.