xiedeyantu commented on code in PR #21362:
URL: https://github.com/apache/datafusion/pull/21362#discussion_r3058256894
##########
datafusion/common/src/functional_dependencies.rs:
##########
@@ -590,6 +590,46 @@ pub fn get_required_group_by_exprs_indices(
.collect()
}
+/// Returns indices for the minimal subset of ORDER BY expressions that are
+/// functionally equivalent to the original set of ORDER BY expressions.
+pub fn get_required_sort_exprs_indices(
+ schema: &DFSchema,
+ sort_expr_names: &[String],
+) -> Option<Vec<usize>> {
+ let dependencies = schema.functional_dependencies();
+ let field_names = schema.field_names();
+
+ let mut known_field_indices = HashSet::new();
+ let mut required_sort_expr_indices = Vec::new();
+
+ for (sort_expr_idx, sort_expr_name) in sort_expr_names.iter().enumerate() {
+ let Some(field_idx) = field_names
Review Comment:
I have Added some comments.
##########
datafusion/common/src/functional_dependencies.rs:
##########
@@ -590,6 +590,46 @@ pub fn get_required_group_by_exprs_indices(
.collect()
}
+/// Returns indices for the minimal subset of ORDER BY expressions that are
+/// functionally equivalent to the original set of ORDER BY expressions.
+pub fn get_required_sort_exprs_indices(
+ schema: &DFSchema,
+ sort_expr_names: &[String],
+) -> Option<Vec<usize>> {
+ let dependencies = schema.functional_dependencies();
+ let field_names = schema.field_names();
+
+ let mut known_field_indices = HashSet::new();
+ let mut required_sort_expr_indices = Vec::new();
+
+ for (sort_expr_idx, sort_expr_name) in sort_expr_names.iter().enumerate() {
+ let Some(field_idx) = field_names
+ .iter()
+ .position(|field_name| field_name == sort_expr_name)
+ else {
+ required_sort_expr_indices.push(sort_expr_idx);
+ continue;
+ };
+
+ let removable = dependencies.deps.iter().any(|dependency| {
+ dependency.target_indices.contains(&field_idx)
+ && dependency
+ .source_indices
+ .iter()
+ .all(|source_idx| known_field_indices.contains(source_idx))
+ });
Review Comment:
Yes, done!
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