perf(parser): short-circuit _parse_pivots when not at PIVOT/UNPIVOT#7557
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georgesittas merged 1 commit intomainfrom Apr 24, 2026
Merged
perf(parser): short-circuit _parse_pivots when not at PIVOT/UNPIVOT#7557georgesittas merged 1 commit intomainfrom
georgesittas merged 1 commit intomainfrom
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…/UNPIVOT _parse_pivots runs once per Join and most table refs, but always builds an iter+list even when the next token can never start a PIVOT clause. Guard on the token type up front so the common no-pivot path is a single check. Small but consistent win under mypyc (~1-3% on join-heavy queries like many_joins). No behavior change.
Contributor
SQLGlot Integration Test ResultsComparing:
By Dialect
Overallmain: 113234 total, 112044 passed (pass rate: 98.9%), sqlglot version: sqlglot:parse-pivots-guard: 110925 total, 110027 passed (pass rate: 99.2%), sqlglot version: Transitions: Dialect pair changes: 0 previous results not found, 1 current results not found ✅ 34 test(s) passed |
georgesittas
approved these changes
Apr 24, 2026
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Summary
`_parse_pivots` is called once per Join and after most table refs, but always builds a callable-iterator + `list()` even when the next token can never start a `PIVOT`/`UNPIVOT` clause. Guard on the token type up front so the common no-pivot path is a single membership check.
Perf
Measured on the 200-JOIN `many_joins` benchmark with `sqlglot[c]`:
~3% faster on join-heavy parses. Perf report showed `_parse_pivots` at 1.89% of parse before; the change reduces it to near zero in the common case. No measurable effect on pure Python (interpreter overhead dominates).
Test plan