diff --git a/src/frontend/src/optimizer/plan_node/generic/scan.rs b/src/frontend/src/optimizer/plan_node/generic/scan.rs
index 57323e01c5330..526a677e279b5 100644
--- a/src/frontend/src/optimizer/plan_node/generic/scan.rs
+++ b/src/frontend/src/optimizer/plan_node/generic/scan.rs
@@ -17,7 +17,6 @@ use std::rc::Rc;
 
 use educe::Educe;
 use fixedbitset::FixedBitSet;
-use itertools::Itertools;
 use pretty_xmlish::Pretty;
 use risingwave_common::catalog::{ColumnDesc, Field, Schema, TableDesc};
 use risingwave_common::util::column_index_mapping::ColIndexMapping;
diff --git a/src/frontend/src/optimizer/plan_node/logical_scan.rs b/src/frontend/src/optimizer/plan_node/logical_scan.rs
index 2f05cdc753182..e671f7412c661 100644
--- a/src/frontend/src/optimizer/plan_node/logical_scan.rs
+++ b/src/frontend/src/optimizer/plan_node/logical_scan.rs
@@ -232,17 +232,18 @@ impl LogicalScan {
             return (self.core.clone(), Condition::true_cond(), None);
         }
 
-        let mut mapping = ColIndexMapping::with_target_size(
-            self.required_col_idx().iter().map(|i| Some(*i)).collect(),
-            self.table_desc().columns.len(),
-        );
-        // Since `required_col_idx` mapping is not invertible, we need to inverse manually.
-        let mut inverse_map = vec![None; mapping.target_size()];
-        for (src, dst) in mapping.mapping_pairs() {
-            inverse_map[dst] = Some(src);
-        }
-        let mut inverse_mapping =
-            ColIndexMapping::with_target_size(inverse_map, mapping.source_size());
+        let mut inverse_mapping = {
+            let mapping = ColIndexMapping::with_target_size(
+                self.required_col_idx().iter().map(|i| Some(*i)).collect(),
+                self.table_desc().columns.len(),
+            );
+            // Since `required_col_idx` mapping is not invertible, we need to inverse manually.
+            let mut inverse_map = vec![None; mapping.target_size()];
+            for (src, dst) in mapping.mapping_pairs() {
+                inverse_map[dst] = Some(src);
+            }
+            ColIndexMapping::with_target_size(inverse_map, mapping.source_size())
+        };
 
         predicate = predicate.rewrite_expr(&mut inverse_mapping);