blaginin commented on code in PR #14684:
URL: https://github.com/apache/datafusion/pull/14684#discussion_r2121659097
##########
datafusion/core/src/dataframe/mod.rs:
##########
@@ -1972,41 +1972,85 @@ impl DataFrame {
.config_options()
.sql_parser
.enable_ident_normalization;
+
let old_column: Column = if ident_opts {
Column::from_qualified_name(old_name)
} else {
Column::from_qualified_name_ignore_case(old_name)
};
- let (qualifier_rename, field_rename) =
- match self.plan.schema().qualified_field_from_column(&old_column) {
- Ok(qualifier_and_field) => qualifier_and_field,
- // no-op if field not found
- Err(DataFusionError::SchemaError(
- SchemaError::FieldNotFound { .. },
- _,
- )) => return Ok(self),
- Err(err) => return Err(err),
- };
- let projection = self
- .plan
- .schema()
- .iter()
- .map(|(qualifier, field)| {
- if qualifier.eq(&qualifier_rename) && field.as_ref() ==
field_rename {
- (
- col(Column::from((qualifier, field)))
- .alias_qualified(qualifier.cloned(), new_name),
- false,
- )
- } else {
- (col(Column::from((qualifier, field))), false)
- }
- })
- .collect::<Vec<_>>();
- let project_plan = LogicalPlanBuilder::from(self.plan)
- .project_with_validation(projection)?
- .build()?;
+ let project_plan = if let LogicalPlan::Projection(Projection {
Review Comment:
It is indeed removed at the optimisation step! The idea behind that PR was
that sometimes you might want to call functions involving expr tree traversal
before performing optimisations. For example:
1. Create a df
2. Rename a lot of columns
3. Call something like `replace_params_with_values` ← then, it'll iterate
over a lot of projection layers
However, after revisiting the PR half a year later 😁, I feel like:
- this isn't actually a problem (spent 30 mins and couldn't easily reproduce
the problem)
- it's very niche
- it does make the code more complicated
So I'll close the PR for now, but will keep an eye on related issues and
resubmit if it turns out to be a real problem.
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