diff --git a/deps/oblib/src/common/object/ob_object.cpp b/deps/oblib/src/common/object/ob_object.cpp
index a5910b461b..7f4375bd11 100644
--- a/deps/oblib/src/common/object/ob_object.cpp
+++ b/deps/oblib/src/common/object/ob_object.cpp
@@ -560,8 +560,13 @@ int ObLobLocatorV2::get_disk_locator(ObString &disc_loc_buff) const
     COMMON_LOG(WARN, "Lob: get disk locator failed", K(ret));
   } else {
     int64_t handle_size = reinterpret_cast<intptr_t>(disk_loc) - reinterpret_cast<intptr_t>(ptr_);
-    handle_size = size_ - handle_size;
-    disc_loc_buff.assign_ptr(reinterpret_cast<const char *>(disk_loc), handle_size);
+    if (handle_size > size_) {
+      ret = OB_ERR_UNEXPECTED;
+      LOG_WARN("get invalid handle size", K(ret), K(size_), K(disk_loc), K(ptr_));
+    } else {
+      handle_size = size_ - handle_size;
+      disc_loc_buff.assign_ptr(reinterpret_cast<const char *>(disk_loc), handle_size);
+    }
   }
   return ret;
 }
@@ -624,8 +629,8 @@ bool ObLobLocatorV2::is_empty_lob() const
   bool bret = false;
   ObString disk_loc_buff;
   ObMemLobCommon *loc = reinterpret_cast<ObMemLobCommon *>(ptr_);
-  if (!has_lob_header_) {
-    bret = (ptr_ == NULL && size_ == 0);
+  if (!has_lob_header_ || size_ == 0) {
+    bret = (size_ == 0);
   } else if (!is_lob_disk_locator() && loc->is_simple()) {
     bret = (size_ - MEM_LOB_COMMON_HEADER_LEN == 0);
   } else if (OB_FAIL(get_disk_locator(disk_loc_buff))) {
diff --git a/src/sql/engine/expr/ob_expr_initcap.cpp b/src/sql/engine/expr/ob_expr_initcap.cpp
index b27a50b896..444fc08f84 100644
--- a/src/sql/engine/expr/ob_expr_initcap.cpp
+++ b/src/sql/engine/expr/ob_expr_initcap.cpp
@@ -176,7 +176,8 @@ int calc_initcap_expr(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res_datum)
       } else if (OB_FAIL(output_result.init(input_byte_len * case_multiply))) {
         LOG_WARN("init stringtext result failed");
       } else if (input_byte_len == 0) {
-        output_result.set_result();
+        // do nothing, let res_str become empty string
+        res_str.assign_ptr(NULL, 0);
       } else if (OB_FAIL(output_result.get_reserved_buffer(res_buf, buf_size))) {
         LOG_WARN("stringtext result reserve buffer failed");
       } else {
@@ -204,7 +205,7 @@ int calc_initcap_expr(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res_datum)
       }
     }
     if (OB_SUCC(ret)) {
-      if (0 == res_str.length() || ob_is_empty_lob(expr.datum_meta_.type_, res_datum, expr.obj_meta_.has_lob_header())) {
+      if (0 == res_str.length()) {
         // initcap is only for oracle mode. set res be null when string length is 0.
         res_datum.set_null();
       } else {
diff --git a/src/sql/resolver/dml/ob_dml_resolver.cpp b/src/sql/resolver/dml/ob_dml_resolver.cpp
index bc07a45a45..4967acf46b 100755
--- a/src/sql/resolver/dml/ob_dml_resolver.cpp
+++ b/src/sql/resolver/dml/ob_dml_resolver.cpp
@@ -5877,6 +5877,10 @@ int ObDMLResolver::do_resolve_subquery_info(const ObSubQueryInfo &subquery_info,
         const ObExprResType &column_type = target_expr->get_result_type();
         if (OB_FAIL(subquery_info.ref_expr_->add_column_type(column_type))) {
           LOG_WARN("add column type to subquery ref expr failed", K(ret));
+        } else if (column_type.is_lob_storage() && !IS_CLUSTER_VERSION_BEFORE_4_1_0_0) {
+          ObExprResType &last_item = subquery_info.ref_expr_->get_column_types().
+                                     at(subquery_info.ref_expr_->get_column_types().count() - 1);
+          last_item.set_has_lob_header();
         }
       }
     }
diff --git a/src/sql/resolver/expr/ob_raw_expr_util.cpp b/src/sql/resolver/expr/ob_raw_expr_util.cpp
index c01248b77f..9c0f0eb800 100644
--- a/src/sql/resolver/expr/ob_raw_expr_util.cpp
+++ b/src/sql/resolver/expr/ob_raw_expr_util.cpp
@@ -5714,7 +5714,7 @@ int ObRawExprUtils::init_column_expr(const ObColumnSchemaV2 &column_schema, ObCo
                                            column_schema.get_column_name_str().length());
   column_expr.set_column_flags(column_schema.get_column_flags());
   column_expr.set_hidden_column(column_schema.is_hidden());
-  column_expr.set_lob_column(ob_is_text_tc(column_schema.get_data_type()));
+  column_expr.set_lob_column(is_lob_storage(column_schema.get_data_type()));
   column_expr.set_is_rowkey_column(column_schema.is_rowkey_column());
   column_expr.set_srs_id(column_schema.get_srs_id());
   if (ob_is_string_type(column_schema.get_data_type())