diff --git a/src/observer/table/ob_table_cg_service.cpp b/src/observer/table/ob_table_cg_service.cpp
index 22a3f67305..0d68e30dbb 100644
--- a/src/observer/table/ob_table_cg_service.cpp
+++ b/src/observer/table/ob_table_cg_service.cpp
@@ -226,7 +226,7 @@ int ObTableExprCgService::generate_current_timestamp_expr(ObTableCtx &ctx,
   int ret = OB_SUCCESS;
   ObSysFunRawExpr *tmp_expr = NULL;
 
-  if (!IS_DEFAULT_NOW_OBJ(item.default_value_)) {
+  if ((!IS_DEFAULT_NOW_OBJ(item.default_value_)) && (!item.auto_filled_timestamp_)) {
     ret = OB_INVALID_ARGUMENT;
     LOG_WARN("invalid column item", K(ret), K(item));
   } else if (OB_ISNULL(item.expr_)) {
@@ -440,7 +440,7 @@ int ObTableExprCgService::generate_assign_expr(ObTableCtx &ctx, ObTableAssignmen
     if (OB_FAIL(generate_autoinc_nextval_expr(ctx, *item, tmp_expr))) {
       LOG_WARN("fail to generate autoinc nextval expr", K(ret));
     }
-  } else if (IS_DEFAULT_NOW_OBJ(item->default_value_)) { // defualt current time
+  } else if (IS_DEFAULT_NOW_OBJ(item->default_value_) || item->auto_filled_timestamp_) { // defualt current time or on update current_timestamp
     if (OB_FAIL(generate_current_timestamp_expr(ctx, *item, tmp_expr))) {
       LOG_WARN("fail to generate autoinc nextval expr", K(ret));
     }
diff --git a/src/observer/table/ob_table_session_pool.cpp b/src/observer/table/ob_table_session_pool.cpp
index 8509b53dc1..916fabe33f 100644
--- a/src/observer/table/ob_table_session_pool.cpp
+++ b/src/observer/table/ob_table_session_pool.cpp
@@ -570,8 +570,7 @@ int ObTableApiSessPool::replace_sess_node_safe(ObTableApiCredential &credential)
 
 void ObTableApiSessNodeVal::destroy()
 {
-  sess_info_.destroy();
-  allocator_.reset();
+  sess_info_.~ObSQLSessionInfo();
   is_inited_ = false;
   owner_node_ = nullptr;
 }
@@ -592,7 +591,6 @@ int ObTableApiSessNodeVal::init_sess_info()
       LOG_WARN("tenant schema is null", K(ret));
     } else if (OB_FAIL(ObTableApiSessUtil::init_sess_info(MTL_ID(),
                                                           tenant_schema->get_tenant_name_str(),
-                                                          &allocator_,
                                                           schema_guard,
                                                           sess_info_))) {
       LOG_WARN("fail to init sess info", K(ret), K(MTL_ID()));
@@ -790,16 +788,12 @@ int ObTableApiSessForeachOp::operator()(MapKV &entry)
 
 int ObTableApiSessUtil::init_sess_info(uint64_t tenant_id,
                                        const common::ObString &tenant_name,
-                                       ObIAllocator *allocator,
                                        ObSchemaGetterGuard &schema_guard,
                                        sql::ObSQLSessionInfo &sess_info)
 {
   int ret = OB_SUCCESS;
 
-  if (OB_ISNULL(allocator)) {
-    ret = OB_INVALID_ARGUMENT;
-    LOG_WARN("allocator is null", K(ret));
-  } else if (OB_FAIL(sess_info.init(0, 0, allocator))) {
+  if (OB_FAIL(sess_info.init(0, 0, nullptr))) {
     LOG_WARN("fail to init session into", K(ret));
   } else if (OB_FAIL(sess_info.init_tenant(tenant_name, tenant_id))) {
     LOG_WARN("fail to init session tenant", K(ret), K(tenant_id));
diff --git a/src/observer/table/ob_table_session_pool.h b/src/observer/table/ob_table_session_pool.h
index 25f34ce08d..9c9ea19b85 100644
--- a/src/observer/table/ob_table_session_pool.h
+++ b/src/observer/table/ob_table_session_pool.h
@@ -128,8 +128,7 @@ friend class ObTableApiSessNode;
 friend class ObTableApiSessGuard;
 public:
   explicit ObTableApiSessNodeVal(ObTableApiSessNode *owner)
-      : allocator_("TbSessNodeVal", OB_MALLOC_NORMAL_BLOCK_SIZE, MTL_ID()),
-        is_inited_(false),
+      : is_inited_(false),
         owner_node_(owner)
   {}
   TO_STRING_KV(K_(is_inited),
@@ -144,7 +143,6 @@ public:
   }
   void give_back_to_free_list();
 private:
-  common::ObArenaAllocator allocator_;
   bool is_inited_;
   sql::ObSQLSessionInfo sess_info_;
   ObTableApiSessNode *owner_node_;
@@ -312,7 +310,6 @@ class ObTableApiSessUtil final
 public:
   static int init_sess_info(uint64_t tenant_id,
                             const common::ObString &tenant_name,
-                            common::ObIAllocator *allocator,
                             share::schema::ObSchemaGetterGuard &schema_guard,
                             sql::ObSQLSessionInfo &sess_info);
 private:
diff --git a/unittest/observer/table/test_table_sess_pool.cpp b/unittest/observer/table/test_table_sess_pool.cpp
index ea6b6194aa..4af3784a4f 100644
--- a/unittest/observer/table/test_table_sess_pool.cpp
+++ b/unittest/observer/table/test_table_sess_pool.cpp
@@ -143,6 +143,7 @@ TEST_F(TestTableSessPool, mgr_get_session)
   const ObTableApiCredential *cred = nullptr;
   ASSERT_EQ(OB_SUCCESS, guard.get_credential(cred));
   ASSERT_NE(nullptr, cred);
+  mgr->destroy();
 }
 
 TEST_F(TestTableSessPool, mgr_update_session)