Omega359 commented on code in PR #14684:
URL: https://github.com/apache/datafusion/pull/14684#discussion_r2282438652
##########
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:
While it may not be a problem exactly I do think it may be worth it for
cases where a large number of with_column (thus projections) are happening.
You can see from a [sample
instrumentation](https://gist.github.com/Omega359/bf96eff97e6dc784e0cfd6a81bfa7b67)
for a dataframe operation I do that handling the projections is take a long
time:
`Optimization for rule optimize_projections took > 50ms: 22821 ms`
The logical plan is 31MB in text (`.display_indent()`) and you can see just
how nested things can get just from the document map in Notepad++
<img width="1911" height="1129" alt="image"
src="https://github.com/user-attachments/assets/c41fda8a-d4af-40b5-b76a-f3eabf0785f4";
/>
I posted about improving the planning performance via multithreading in the
[discord
channel](https://discord.com/channels/885562378132000778/1166447479609376850/1406384187228819680)
but from a quick look I'm not sure that approach will necessarily be a simple
change.
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