diff --git a/src/common/backend/nodes/nodeFuncs.cpp b/src/common/backend/nodes/nodeFuncs.cpp
index 17a9d9512..25d40d65e 100644
--- a/src/common/backend/nodes/nodeFuncs.cpp
+++ b/src/common/backend/nodes/nodeFuncs.cpp
@@ -2098,8 +2098,7 @@ bool expression_tree_walker(Node* node, bool (*walker)(), void* context)
         case T_PrefixKey:
             return p2walker(((PrefixKey*)node)->arg, context);
         case T_UserSetElem: {
-            p2walker(((UserSetElem*)node)->val, context);
-            return true;
+            return p2walker(((UserSetElem*)node)->val, context);
         }
         case T_PriorExpr:
             return p2walker(((PriorExpr*)node)->node, context);
diff --git a/src/gausskernel/optimizer/util/clauses.cpp b/src/gausskernel/optimizer/util/clauses.cpp
index b447c3ecf..2568542f7 100644
--- a/src/gausskernel/optimizer/util/clauses.cpp
+++ b/src/gausskernel/optimizer/util/clauses.cpp
@@ -1191,6 +1191,9 @@ static bool contain_specified_functions_walker(Node* node, check_function_contex
     } else if (IsA(node, Query) && context->deep) {
         /* Recurse into subselects */
         return query_tree_walker((Query*)node, (bool (*)())contain_specified_functions_walker<isSimpleVar>, context, 0);
+    } else if (IsA(node, UserSetElem)) {
+        /* UserSetElem is volatile */
+        return context->checktype == CONTAIN_VOLATILE_FUNTION;
     }
     return expression_tree_walker(node, (bool (*)())contain_specified_functions_walker<isSimpleVar>, context);
 }
diff --git a/src/test/regress/input/set_user_defined_variables_test.source b/src/test/regress/input/set_user_defined_variables_test.source
index f9f9e8075..dd770ef73 100644
--- a/src/test/regress/input/set_user_defined_variables_test.source
+++ b/src/test/regress/input/set_user_defined_variables_test.source
@@ -774,6 +774,13 @@ END WHILE label_1;
 end;
 /
 SELECT TRIM(TRAILING ', ' FROM @sequence);
+
+set enable_set_variable_b_format = 1;
+CREATE TABLE userset_t1 (a VARCHAR(500) CHARACTER SET UTF8);
+SET @num=1000;
+INSERT INTO userset_t1 VALUES (CONCAT((@num:=@num+1), 'a'));
+
+set enable_set_variable_b_format = default;
 \c regression
 drop database if exists test_set;
 
diff --git a/src/test/regress/output/set_user_defined_variables_test.source b/src/test/regress/output/set_user_defined_variables_test.source
index 032412d9c..b5f693d4c 100644
--- a/src/test/regress/output/set_user_defined_variables_test.source
+++ b/src/test/regress/output/set_user_defined_variables_test.source
@@ -1520,6 +1520,11 @@ SELECT TRIM(TRAILING ', ' FROM @sequence);
  1, 2, 3, 4, 5, 6, 7, 8, 9, 10
 (1 row)
 
+set enable_set_variable_b_format = 1;
+CREATE TABLE userset_t1 (a VARCHAR(500) CHARACTER SET UTF8);
+SET @num=1000;
+INSERT INTO userset_t1 VALUES (CONCAT((@num:=@num+1), 'a'));
+set enable_set_variable_b_format = default;
 \c regression
 drop database if exists test_set;
 \! @abs_bindir@/gs_guc reload -Z datanode -D @abs_srcdir@/tmp_check/datanode1 -c "enable_set_variable_b_format=off" >/dev/null 2>&1