mingmwang commented on code in PR #5661:
URL: https://github.com/apache/arrow-datafusion/pull/5661#discussion_r1155444291
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datafusion/physical-expr/src/utils.rs:
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@@ -312,6 +305,91 @@ pub fn ordering_satisfy_requirement_concrete<F: FnOnce()
-> EquivalencePropertie
}
}
+/// Checks whether the given [`PhysicalSortRequirement`]s are equal or more
+/// specific than the provided [`PhysicalSortRequirement`]s.
+pub fn requirements_compatible<F: FnOnce() -> EquivalenceProperties>(
+ provided: Option<&[PhysicalSortRequirement]>,
+ required: Option<&[PhysicalSortRequirement]>,
+ equal_properties: F,
+) -> bool {
+ match (provided, required) {
+ (_, None) => true,
+ (None, Some(_)) => false,
+ (Some(provided), Some(required)) => {
+ requirements_compatible_concrete(provided, required,
equal_properties)
+ }
+ }
+}
+
+/// Checks whether the given [`PhysicalSortRequirement`]s are equal or more
+/// specific than the provided [`PhysicalSortRequirement`]s.
+fn requirements_compatible_concrete<F: FnOnce() -> EquivalenceProperties>(
+ provided: &[PhysicalSortRequirement],
+ required: &[PhysicalSortRequirement],
+ equal_properties: F,
+) -> bool {
+ if required.len() > provided.len() {
+ false
+ } else if required
+ .iter()
+ .zip(provided.iter())
+ .all(|(req, given)| given.compatible(req))
+ {
+ true
+ } else if let eq_classes @ [_, ..] = equal_properties().classes() {
+ required
+ .iter()
+ .map(|e| {
+ normalize_sort_requirement_with_equivalence_properties(
+ e.clone(),
+ eq_classes,
+ )
+ })
+ .zip(provided.iter().map(|e| {
+ normalize_sort_requirement_with_equivalence_properties(
+ e.clone(),
+ eq_classes,
+ )
+ }))
+ .all(|(req, given)| given.compatible(&req))
+ } else {
+ false
+ }
+}
+
+/// This function maps back requirement after ProjectionExec
+/// to the Executor for its input.
+// Specifically, `ProjectionExec` changes index of `Column`s in the schema of
its input executor.
+// This function changes requirement given according to ProjectionExec schema
to the requirement
+// according to schema of input executor to the ProjectionExec.
+// For instance, Column{"a", 0} would turn to Column{"a", 1}. Please note that
this function assumes that
+// name of the Column is unique. If we have a requirement such that
Column{"a", 0}, Column{"a", 1}.
+// This function will produce incorrect result (It will only emit single
Column as a result).
+pub fn map_columns_before_projection(
Review Comment:
Nice comment !
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