From 28344d96dbcc1eae935335d12da2e661b97ed4c7 Mon Sep 17 00:00:00 2001
From: Igor Izvekov <izveigor@mail.ru>
Date: Fri, 24 Feb 2023 15:02:56 +0300
Subject: [PATCH] Optimization of the function "intersect"

---
 datafusion/optimizer/src/eliminate_cross_join.rs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/datafusion/optimizer/src/eliminate_cross_join.rs b/datafusion/optimizer/src/eliminate_cross_join.rs
index c19b43d297e3..29827a3557ff 100644
--- a/datafusion/optimizer/src/eliminate_cross_join.rs
+++ b/datafusion/optimizer/src/eliminate_cross_join.rs
@@ -247,10 +247,12 @@ fn intersect(
     vec1: &[(Expr, Expr)],
     vec2: &[(Expr, Expr)],
 ) {
-    for x1 in vec1.iter() {
-        for x2 in vec2.iter() {
-            if x1.0 == x2.0 && x1.1 == x2.1 || x1.1 == x2.0 && x1.0 == x2.1 {
-                accum.push((x1.0.clone(), x1.1.clone()));
+    if !(vec1.is_empty() || vec2.is_empty()) {
+        for x1 in vec1.iter() {
+            for x2 in vec2.iter() {
+                if x1.0 == x2.0 && x1.1 == x2.1 || x1.1 == x2.0 && x1.0 == x2.1 {
+                    accum.push((x1.0.clone(), x1.1.clone()));
+                }
             }
         }
     }