geoffreyclaude commented on code in PR #15563:
URL: https://github.com/apache/datafusion/pull/15563#discussion_r2031026473
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datafusion/physical-expr/src/equivalence/properties/mod.rs:
##########
@@ -575,10 +576,35 @@ impl EquivalenceProperties {
// From the analysis above, we know that `[a ASC]` is satisfied.
Then,
// we add column `a` as constant to the algorithm state. This
enables us
// to deduce that `(b + c) ASC` is satisfied, given `a` is
constant.
- eq_properties = eq_properties
-
.with_constants(std::iter::once(ConstExpr::from(normalized_req.expr)));
+ eq_properties = eq_properties.with_constants(std::iter::once(
+ ConstExpr::from(Arc::clone(&normalized_req.expr)),
+ ));
}
- true
+
+ // All requirements are satisfied.
+ normalized_reqs.len()
+ }
+
+ /// Determines the longest prefix of `reqs` that is satisfied by the
existing ordering.
+ /// Returns that prefix as a new `LexRequirement`, and a boolean
indicating if all the requirements are satisfied.
+ pub fn extract_matching_prefix(
+ &self,
+ reqs: &LexRequirement,
+ ) -> (LexRequirement, bool) {
+ // First, standardize the given requirement:
+ let normalized_reqs = self.normalize_sort_requirements(reqs);
Review Comment:
Great suggestion! It seems I missed a spot in the `EnforceSorting` optimizer
rule, which currently removes the TopK in some cases. I'll update the code and
unit tests with this case.
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