Reuse query objects and skip re-parsing parsed tag lists - #91
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igor-alexandrov merged 1 commit intoAug 18, 2026
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Every tagged_with call built a fresh QueryBuilder and TagsQuery even though both are stateless, and GenericParser rebuilt a TagList it had itself produced. All of that work has the same result on every call, so it was pure per-query allocation overhead. QueryBuilder now exposes a shared frozen instance with the two TagsQuery strategies (all/any) prebuilt, and the parser returns TagList input as-is. Parsing an already-parsed list drops from ~0.7us to ~0.05us; relation building gets ~2-4% cheaper. Behavior is unchanged except that a hand-built TagList containing empty strings is no longer filtered — Metka itself never produces one. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This was referenced Aug 18, 2026
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Why
The benchmark suite showed Metka statistically tied with acts-as-taggable-array-on on querying — both emit identical SQL against the same GIN index — but Metka's Ruby-side relation building carried avoidable per-call work: a fresh
QueryBuilderandTagsQueryon everytagged_withcall despite both being stateless, andGenericParserrebuildingTagListinput that is its own, already-parsed output.What
QueryBuilderexposes a shared frozen.instance; the twoTagsQuerystrategies (:all/:any) are prebuilt in a frozenSTRATEGIESconstant..newremains public, so direct construction (as in the unit tests) still works.tagged_withuses the shared instance.GenericParser#callreturns aTagListargument as-is instead of re-parsing it.Numbers
Micro-benchmark of relation construction (no DB round trip), before → after:
parser.call(TagList)tagged_with(...).to_sqlBehavior note
A hand-built
TagListcontaining empty strings is no longer filtered on re-parse. Metka itself never produces such a list, so no gem path or test is affected.Tests
Full suite: 116 runs, 311 assertions, 0 failures, 0 errors.
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