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perf(substrait): avoid quadratic field lookup when consuming ReadRel - #26190
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`ensure_schema_compatibility` and `apply_projection` looked up every field
of the Substrait base schema with a linear scan of the table schema, making
consumption of a read over a wide table O(m*n). Build a name->index map of
the table schema once instead. Missing or duplicated names fall back to the
existing DFSchema lookups, so errors and disambiguation are unchanged.
Add a `consume_wide_read` benchmark. Consume time for `SELECT c0` over a
table with N columns:
columns before after
100 58 us 25.5 us
1000 2.33 ms 276 us
10000 211 ms 3.16 ms
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
bvolpato
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Oct 11, 2026
bvolpato
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LGTM, thanks for the improvement. The fast path preserves the existing lookup fallback for missing and duplicate names. Substrait checks, Clippy, and the wide-read benchmark smoke run pass locally.
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ensure_schema_compatibilityandapply_projectionlooked up every field of the Substrait base schema with a linear scan of the table schema, making consumption of a read over a wide table O(m*n). Build a name->index map of the table schema once instead. Missing or duplicated names fall back to the existing DFSchema lookups, so errors and disambiguation are unchanged.Add a
consume_wide_readbenchmark. Consume time forSELECT c0over a table with N columns: