diff --git a/src/sql/dblink/ob_dblink_utils.cpp b/src/sql/dblink/ob_dblink_utils.cpp
index 613c6eef2..db33a5b35 100644
--- a/src/sql/dblink/ob_dblink_utils.cpp
+++ b/src/sql/dblink/ob_dblink_utils.cpp
@@ -800,23 +800,33 @@ int ObDblinkCtxInSession::clean_dblink_conn(const bool force_disconnect)
   int ret = OB_SUCCESS;
 #ifdef OB_BUILD_DBLINK
   uint32_t sessid = 0;
-  common::sqlclient::ObISQLConnection *dblink_conn =NULL;
-  oceanbase::common::sqlclient::ObTenantDblinkKeeper *tenant_dblink_keeper = MTL(oceanbase::common::sqlclient::ObTenantDblinkKeeper*);
-  if (OB_ISNULL(tenant_dblink_keeper)) {
+  common::sqlclient::ObISQLConnection *dblink_conn = NULL;
+  // Why do not use MTL(oceanbase::common::sqlclient::ObTenantDblinkKeeper*) ?
+  // MTL(xxx) accesses the ptr in the cache, we need to access the ptr in the memory.
+  // In the following scene，we need to know if MTL(ObTenantDblinkKeeper*) has been destroyed or not:
+  // MTL(ObTenantDblinkKeeper*) destroy firstly, MTL(ObTableApiSessPoolMgr*) destroy later.
+  // When MTL(ObTableApiSessPoolMgr*) destroy, it will destruct ObSQLSessionInfo which will clean dblink in reset(),
+  // so we need to know if MTL(ObTenantDblinkKeeper*) has been destroyed to avoid accessing the memory that has been destroyed
+  if (OB_ISNULL(MTL_CTX())) {
     // do nothing
-  } else if (OB_ISNULL(session_info_)) {
-    ret = OB_ERR_UNEXPECTED;
-    LOG_WARN("unexcepted null ptr", K(ret), KP(session_info_), KP(tenant_dblink_keeper));
-  } else if (FALSE_IT(sessid = session_info_->get_sessid())) {
-  } else if (OB_FAIL(tenant_dblink_keeper->clean_dblink_conn(sessid, force_disconnect))) {
-    LOG_WARN("failed to set dblink", KP(dblink_conn), K(sessid), KP(tenant_dblink_keeper), K(force_disconnect), K(ret));
+  } else {
+    oceanbase::common::sqlclient::ObTenantDblinkKeeper *tenant_dblink_keeper = MTL_CTX()->get<oceanbase::common::sqlclient::ObTenantDblinkKeeper *>();
+    if (OB_ISNULL(tenant_dblink_keeper)) {
+      // do nothing
+    } else if (OB_ISNULL(session_info_)) {
+      ret = OB_ERR_UNEXPECTED;
+      LOG_WARN("unexcepted null ptr", K(ret), KP(session_info_), KP(tenant_dblink_keeper));
+    } else if (FALSE_IT(sessid = session_info_->get_sessid())) {
+    } else if (OB_FAIL(tenant_dblink_keeper->clean_dblink_conn(sessid, force_disconnect))) {
+      LOG_WARN("failed to set dblink", KP(dblink_conn), K(sessid), KP(tenant_dblink_keeper), K(force_disconnect), K(ret));
+    }
+    tx_id_.reset();
+    arena_alloc_.reset();
+    reverse_dblink_ = NULL;
+    reverse_dblink_buf_ = NULL;
+    sys_var_reverse_info_buf_ = NULL;
+    sys_var_reverse_info_buf_size_ = 0;
   }
-  tx_id_.reset();
-  arena_alloc_.reset();
-  reverse_dblink_ = NULL;
-  reverse_dblink_buf_ = NULL;
-  sys_var_reverse_info_buf_ = NULL;
-  sys_var_reverse_info_buf_size_ = 0;
 #endif
   return ret;
 }
diff --git a/unittest/observer/table/test_create_executor.cpp b/unittest/observer/table/test_create_executor.cpp
index 1e294f215..3ec322276 100644
--- a/unittest/observer/table/test_create_executor.cpp
+++ b/unittest/observer/table/test_create_executor.cpp
@@ -33,6 +33,8 @@ using namespace oceanbase::share::schema;
 using namespace oceanbase::observer;
 using namespace oceanbase::pl;
 
+namespace oceanbase
+{
 // copy from test_table_schema.cpp
 void fill_table_schema(ObTableSchema &table)
 {
@@ -162,6 +164,7 @@ void TestCreateExecutor::SetUp()
 
 void TestCreateExecutor::TearDown()
 {
+  MTL_CTX()=nullptr;
 }
 
 ObTableApiSessNodeVal g_sess_node_val(NULL, 500);
@@ -471,39 +474,6 @@ TEST_F(TestCreateExecutor, cons_column_type)
   ASSERT_EQ(1, column_info.type_.get_accuracy().get_length());
 }
 
-TEST_F(TestCreateExecutor, check_column_type)
-{
-  ObTableColumnInfo column_info;
-  column_info.type_.set_result_flag(NOT_NULL_WRITE_FLAG);
-  ObObj obj;
-  uint32_t res_flag = 0;
-  ObTableCtx fake_ctx(allocator_);
-  schema_service_.get_schema_guard(fake_ctx.schema_guard_, 1);
-  fake_ctx_init_common(fake_ctx, &table_schema_);
-
-  // check nullable
-  obj.set_null();
-  res_flag |= NOT_NULL_FLAG;
-  column_info.type_.set_result_flag(res_flag);
-  column_info.is_nullable_ = false;
-  ASSERT_EQ(OB_BAD_NULL_ERROR, fake_ctx.adjust_column_type(column_info, obj));
-  // check data type mismatch
-  res_flag = 0;
-  obj.set_int(1);
-  column_info.type_.set_result_flag(res_flag);
-  column_info.type_.set_type(ObVarcharType);
-  ASSERT_EQ(OB_KV_COLUMN_TYPE_NOT_MATCH, fake_ctx.adjust_column_type(column_info, obj));
-  // check collation
-  obj.set_binary("ttt");
-  column_info.type_.set_collation_type(CS_TYPE_UTF8MB4_GENERAL_CI);
-  ASSERT_EQ(OB_KV_COLLATION_MISMATCH, fake_ctx.adjust_column_type(column_info, obj));
-  // collation convert
-  obj.set_varchar("test");
-  obj.set_collation_type(CS_TYPE_UTF8MB4_BIN);
-  ASSERT_EQ(OB_SUCCESS, fake_ctx.adjust_column_type(column_info, obj));
-  ASSERT_EQ(CS_TYPE_UTF8MB4_GENERAL_CI, obj.get_collation_type());
-}
-
 TEST_F(TestCreateExecutor, generate_key_range)
 {
   ObTableCtx fake_ctx(allocator_);
@@ -580,6 +550,7 @@ TEST_F(TestCreateExecutor, test_cache)
     ASSERT_EQ(TABLE_API_EXEC_INSERT, spec->type_);
   }
 }
+} // end namespace oceanbase
 
 int main(int argc, char **argv)
 {