diff --git a/datafusion/src/logical_plan/plan.rs b/datafusion/src/logical_plan/plan.rs
index b954b6a97950c..fdf94809f16e5 100644
--- a/datafusion/src/logical_plan/plan.rs
+++ b/datafusion/src/logical_plan/plan.rs
@@ -375,12 +375,10 @@ impl LogicalPlan {
                 {
                     self.using_columns.push(
                         on.iter()
-                            .map(|entry| {
-                                std::iter::once(entry.0.clone())
-                                    .chain(std::iter::once(entry.1.clone()))
-                            })
+                            .map(|entry| [&entry.0, &entry.1])
                             .flatten()
-                            .collect::<HashSet<_>>(),
+                            .cloned()
+                            .collect::<HashSet<Column>>(),
                     );
                 }
                 Ok(true)
diff --git a/datafusion/src/optimizer/filter_push_down.rs b/datafusion/src/optimizer/filter_push_down.rs
index 76d8c05bed4c6..399923e87218b 100644
--- a/datafusion/src/optimizer/filter_push_down.rs
+++ b/datafusion/src/optimizer/filter_push_down.rs
@@ -97,9 +97,11 @@ fn get_join_predicates<'a>(
         .fields()
         .iter()
         .map(|f| {
-            std::iter::once(f.qualified_column())
+            [
+                f.qualified_column(),
                 // we need to push down filter using unqualified column as well
-                .chain(std::iter::once(f.unqualified_column()))
+                f.unqualified_column(),
+            ]
         })
         .flatten()
         .collect::<HashSet<_>>();
@@ -107,8 +109,11 @@ fn get_join_predicates<'a>(
         .fields()
         .iter()
         .map(|f| {
-            std::iter::once(f.qualified_column())
-                .chain(std::iter::once(f.unqualified_column()))
+            [
+                f.qualified_column(),
+                // we need to push down filter using unqualified column as well
+                f.unqualified_column(),
+            ]
         })
         .flatten()
         .collect::<HashSet<_>>();