diff --git a/src/gausskernel/optimizer/commands/functioncmds.cpp b/src/gausskernel/optimizer/commands/functioncmds.cpp
index 64e733612..435a7732b 100755
--- a/src/gausskernel/optimizer/commands/functioncmds.cpp
+++ b/src/gausskernel/optimizer/commands/functioncmds.cpp
@@ -98,6 +98,40 @@ static const int PRO_RETURN_SET_COST = 1000;
  * validator, so as not to produce a NOTICE and then an ERROR for the same
  * condition.)
  */
+ static void CheckIsSerialType(TypeName* t)
+{
+    bool isSerial = false;
+    /* Check for SERIAL pseudo-types */
+    if (t && list_length(t->names) == 1 && t->pct_type == false) {
+        char* typname = strVal(linitial(t->names));
+
+        if (strcmp(typname, "smallserial") == 0 || strcmp(typname, "serial2") == 0) {
+            isSerial = true;
+            t->names = NIL;
+            t->typeOid = INT2OID;
+        } else if (strcmp(typname, "serial") == 0 || strcmp(typname, "serial4") == 0) {
+            isSerial = true;
+            t->names = NIL;
+            t->typeOid = INT4OID;
+        } else if (strcmp(typname, "bigserial") == 0 || strcmp(typname, "serial8") == 0) {
+            isSerial = true;
+            t->names = NIL;
+            t->typeOid = INT8OID;
+        } 
+
+        if (isSerial && t->arrayBounds != NIL) {
+            /*
+             * We have to reject "serial[]" explicitly, because once we've set
+             * typeid, LookupTypeName won't notice arrayBounds.  We don't need any
+             * special coding for serial(typmod) though.
+            */
+            ereport(ERROR,
+                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                    errmsg("array of serial is not implemented")));
+        }
+    }
+}
+
 static void compute_return_type(
     TypeName* returnType, Oid languageOid, Oid* prorettype_p, bool* returnsSet_p, bool fenced)
 {
@@ -105,45 +139,13 @@ static void compute_return_type(
     Type typtup;
     AclResult aclresult;
     Oid typowner = InvalidOid;
-    bool isSerial = false;
     /*
      * isalter is true, change the owner of the objects as the owner of the
      * namespace, if the owner of the namespce has the same name as the namescpe
      */
     bool isalter = false;
     
-    /* Check for SERIAL pseudo-types */
-    isSerial = false;
-    if (returnType && list_length(returnType->names) == 1 && returnType->pct_type == false) {
-        char* typname = strVal(linitial(returnType->names));
-
-        if (strcmp(typname, "smallserial") == 0 || strcmp(typname, "serial2") == 0) {
-            isSerial = true;
-            returnType->names = NIL;
-            returnType->typeOid = INT2OID;
-        } else if (strcmp(typname, "serial") == 0 || strcmp(typname, "serial4") == 0) {
-            isSerial = true;
-            returnType->names = NIL;
-            returnType->typeOid = INT4OID;
-        } else if (strcmp(typname, "bigserial") == 0 || strcmp(typname, "serial8") == 0) {
-            isSerial = true;
-            returnType->names = NIL;
-            returnType->typeOid = INT8OID;
-        }
-
-        if (isSerial) {
-            /*
-             * We have to reject "serial[]" explicitly, because once we've set
-             * typeid, LookupTypeName won't notice arrayBounds.  We don't need any
-             * special coding for serial(typmod) though.
-             */
-            if (returnType->arrayBounds != NIL) {
-                ereport(ERROR,
-                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                        errmsg("array of serial is not implemented")));
-            }
-        }
-    }
+    CheckIsSerialType(returnType);
 
     typtup = LookupTypeName(NULL, returnType, NULL);
     /*
@@ -257,7 +259,6 @@ static void examine_parameter_list(List* parameters, Oid languageOid, const char
     int outCount = 0;
     int varCount = 0;
     bool have_names = false;
-    bool isSerial = false;
     ListCell* x = NULL;
     int i;
     ParseState* pstate = NULL;
@@ -284,49 +285,7 @@ static void examine_parameter_list(List* parameters, Oid languageOid, const char
         Type typtup;
         AclResult aclresult;
 
-        /* Check for SERIAL pseudo-types */
-        isSerial = false;
-        if (t && list_length(t->names) == 1 && t->pct_type == false) {
-            char* typname = strVal(linitial(t->names));
-
-            if (strcmp(typname, "smallserial") == 0 || strcmp(typname, "serial2") == 0) {
-                isSerial = true;
-                t->names = NIL;
-                t->typeOid = INT2OID;
-            } else if (strcmp(typname, "serial") == 0 || strcmp(typname, "serial4") == 0) {
-                isSerial = true;
-                t->names = NIL;
-                t->typeOid = INT4OID;
-            } else if (strcmp(typname, "bigserial") == 0 || strcmp(typname, "serial8") == 0) {
-                isSerial = true;
-                t->names = NIL;
-                t->typeOid = INT8OID;
-            }
-
-            if (isSerial) {
-                /*
-                 * We have to reject "serial[]" explicitly, because once we've set
-                 * typeid, LookupTypeName won't notice arrayBounds.  We don't need any
-                 * special coding for serial(typmod) though.
-                 */ 
-                if (t->arrayBounds != NIL) {
-                    ereport(ERROR,
-                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                            errmsg("array of serial is not implemented"))); 
-                }
-            }
-        }
-
-        typtup = LookupTypeName(NULL, t, NULL);
-        /*
-         * If the type is relation, then we check
-         * whether the table is in installation group
-         */
-        if (!in_logic_cluster() && !IsTypeTableInInstallationGroup(typtup)) {
-            ereport(ERROR,
-                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                    errmsg("argument type '%s' must be in installation group", TypeNameToString(t))));
-        }
+        CheckIsSerialType(t);
 
         if (typtup) {
             if (!((Form_pg_type)GETSTRUCT(typtup))->typisdefined) {