[arrow-datafusion] branch main updated: Minor: Avoid some extra plan construction (#5761)

[alamb]

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alamb pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow-datafusion.git


The following commit(s) were added to refs/heads/main by this push:
     new c8a3d5898 Minor: Avoid some extra plan construction (#5761)
c8a3d5898 is described below

commit c8a3d589889dd1e67047de89db8b4ff56f90f04c
Author: Andrew Lamb <and...@nerdnetworks.org>
AuthorDate: Tue Mar 28 20:05:50 2023 +0200

    Minor: Avoid some extra plan construction (#5761)
---
 datafusion/expr/src/tree_node/plan.rs | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/datafusion/expr/src/tree_node/plan.rs 
b/datafusion/expr/src/tree_node/plan.rs
index 122359bf0..e948f90da 100644
--- a/datafusion/expr/src/tree_node/plan.rs
+++ b/datafusion/expr/src/tree_node/plan.rs
@@ -108,11 +108,20 @@ impl TreeNode for LogicalPlan {
     where
         F: FnMut(Self) -> Result<Self>,
     {
-        let children = self.inputs().into_iter().cloned().collect::<Vec<_>>();
-        if !children.is_empty() {
-            let new_children: Result<Vec<_>> =
-                children.into_iter().map(transform).collect();
-            self.with_new_inputs(new_children?.as_slice())
+        let old_children = self.inputs();
+        let new_children = old_children
+            .iter()
+            .map(|&c| c.clone())
+            .map(transform)
+            .collect::<Result<Vec<_>>>()?;
+
+        // if any changes made, make a new child
+        if old_children
+            .iter()
+            .zip(new_children.iter())
+            .any(|(c1, c2)| c1 != &c2)
+        {
+            self.with_new_inputs(new_children.as_slice())
         } else {
             Ok(self)
         }