[GitHub] [arrow-datafusion] houqp commented on a change in pull request #1319: Avoid changing expression names during constant folding

[GitBox <gi...@apache.org>]

houqp commented on a change in pull request #1319:
URL: https://github.com/apache/arrow-datafusion/pull/1319#discussion_r753575943



##########
File path: datafusion/src/optimizer/constant_folding.rs
##########
@@ -101,7 +105,30 @@ impl OptimizerRule for ConstantFolding {
                             // fold constants and then simplify
                             .rewrite(&mut const_evaluator)?
                             .rewrite(&mut simplifier)?;
-                        Ok(new_e)
+
+                        let new_name = &new_e.name(plan.schema());
+
+                        // Some plans will be candidates in projection pushdown rule to
+                        // trim expressions based on expression names. We need to keep
+                        // expression name for them.
+                        let is_plan_for_projection_pushdown = matches!(
+                            plan,
+                            LogicalPlan::Window { .. }

Review comment:
       > For example, for Project, it will create many (looks redundant) aliases. Some looks okay but some looks really weird, e.g. some failed tests:
   
   @viirya the example you gave here looks like correct behavior to me, are you concerned with lots of updates on the tests? or are there other unwanted side effect of this approach?




-- 
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-unsubscribe@arrow.apache.org

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