API: Implement startsWith bounds check in StrictMetricsEvaluator#15902
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bharos wants to merge 1 commit intoapache:mainfrom
Open
API: Implement startsWith bounds check in StrictMetricsEvaluator#15902bharos wants to merge 1 commit intoapache:mainfrom
bharos wants to merge 1 commit intoapache:mainfrom
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StrictMetricsEvaluator.startsWith() previously returned ROWS_MIGHT_NOT_MATCH unconditionally, without using column bounds. This misses the opportunity to determine that all rows in a file must match when both lower and upper bounds start with the given prefix. When both bounds start with the prefix, all values between them must also start with it, so the evaluator can return ROWS_MUST_MATCH. This enables whole-file matching optimizations for prefix-based operations.
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What
Implements bounds-based evaluation for
startsWithinStrictMetricsEvaluator, replacing the unconditionalROWS_MIGHT_NOT_MATCHreturn with actual logic.Previously,
startsWithalways returnedROWS_MIGHT_NOT_MATCH,which prevented the engine from eliminating the residual predicate even
when file-level column bounds made it provable that every value started
with the given prefix.
Changes
StrictMetricsEvaluator.startsWith: Added checks for nestedcolumns, null-containing columns, and lower/upper bound comparisons
against the prefix. Returns
ROWS_MUST_MATCHwhen both bounds startwith the prefix.
TestStrictMetricsEvaluator: Added 9 test methods covering:both bounds match prefix, single-char prefix match, only lower bound
matches, bounds outside prefix range, wider range, missing stats,
all-nulls, some-nulls, and prefix longer than bounds.
How it works
For
STARTS WITH <prefix>:ROWS_MIGHT_NOT_MATCH(conservative)ROWS_MIGHT_NOT_MATCHthe upper bound (truncated to prefix length) equals the prefix →
ROWS_MUST_MATCH(all values in the file start with the prefix)ROWS_MIGHT_NOT_MATCH(conservative)This follows the same pattern used by
eqand the PR fornotStartsWithbounds (#15883) check in this class.Closes #15901