blaginin commented on code in PR #14684:
URL: https://github.com/apache/datafusion/pull/14684#discussion_r1958680507


##########
datafusion/core/src/dataframe/mod.rs:
##########
@@ -1779,37 +1779,82 @@ 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(new_name)
-                } else {
-                    col(Column::from((qualifier, field)))
-                }
-            })
-            .collect::<Vec<_>>();
-        let project_plan = LogicalPlanBuilder::from(self.plan)
-            .project(projection)?
-            .build()?;
+        let project_plan = if let LogicalPlan::Projection(Projection {
+            expr,
+            input,
+            schema,
+            ..
+        }) = self.plan
+        {
+            // special case: we already have a projection on top, so we can 
reuse it rather than creating a new one
+            let (qualifier_rename, field_rename) =
+                match 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 { .. },
+                        _,
+                    )) => {
+                        self.plan = LogicalPlan::Projection(

Review Comment:
   We need to do that because `self` was destructed and so I need to put `plan` 
back. `try_new_with_schema` is quite cheap and this shouldn't be happening 
often anyway



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org
For additional commands, e-mail: github-h...@datafusion.apache.org

Reply via email to