diff --git a/src/common/backend/nodes/nodeFuncs.cpp b/src/common/backend/nodes/nodeFuncs.cpp
index e0e79ff3edb363761f2f8504e4467db3fa905c9c..0ecffd31b3c41751599d3b565408b461fe2e3982 100644
--- a/src/common/backend/nodes/nodeFuncs.cpp
+++ b/src/common/backend/nodes/nodeFuncs.cpp
@@ -2108,8 +2108,7 @@ 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 d61ff1e12791ba829b9797df1e954a1a4dfc3bc6..f910103eca806f8bdad266a8c8eb0679767f7135 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 544038e8cc773d8532d9de949546aa0aff72091e..fe4086f7a6d43612c273711760750df41626fc71 100644
--- a/src/test/regress/input/set_user_defined_variables_test.source
+++ b/src/test/regress/input/set_user_defined_variables_test.source
@@ -789,8 +789,12 @@ SELECT stat_id, @pids := id FROM account_instance_stats where id >= @pids;
 drop table account_instance_stats;
 set enable_seqscan = default;
 set enable_bitmapscan = default;
-set enable_set_variable_b_format = default;
 
+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 19ab1926ab310ca70e23b1485714126ce27bc12b..bfe3ef55d3b9d048bb0f646dc8b8f88955f247ef 100644
--- a/src/test/regress/output/set_user_defined_variables_test.source
+++ b/src/test/regress/output/set_user_defined_variables_test.source
@@ -1541,6 +1541,9 @@ SELECT stat_id, @pids := id FROM account_instance_stats where id >= @pids;
 drop table account_instance_stats;
 set enable_seqscan = default;
 set enable_bitmapscan = default;
+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;