diff --git a/src/storage/blocksstable/index_block/ob_ddl_index_block_row_iterator.cpp b/src/storage/blocksstable/index_block/ob_ddl_index_block_row_iterator.cpp
index 01b7ed0362..e582e6276b 100644
--- a/src/storage/blocksstable/index_block/ob_ddl_index_block_row_iterator.cpp
+++ b/src/storage/blocksstable/index_block/ob_ddl_index_block_row_iterator.cpp
@@ -76,7 +76,7 @@ int ObDDLIndexBlockRowIterator::init(const ObMicroBlockData &idx_block_data,
     is_reverse_scan_ = is_reverse_scan;
     iter_step_ = is_reverse_scan_ ? -1 : 1;
     datum_utils_ = datum_utils;
-    is_co_sstable_ = iter_param.is_valid() ? iter_param.sstable_->is_co_sstable() || ObITable::TableType::DDL_MEM_CO_SSTABLE == iter_param.sstable_->get_key().table_type_ : false;
+    is_co_sstable_ = iter_param.is_valid() ? iter_param.sstable_->is_co_sstable() || iter_param.sstable_->is_ddl_mem_co_cg_sstable() : false;
     is_inited_ = true;
   }
   return ret;
diff --git a/src/storage/blocksstable/index_block/ob_sstable_sec_meta_iterator.cpp b/src/storage/blocksstable/index_block/ob_sstable_sec_meta_iterator.cpp
index 65eb4bf552..161d320448 100644
--- a/src/storage/blocksstable/index_block/ob_sstable_sec_meta_iterator.cpp
+++ b/src/storage/blocksstable/index_block/ob_sstable_sec_meta_iterator.cpp
@@ -103,7 +103,7 @@ int ObSSTableSecMetaIterator::open(
   }
   if (OB_FAIL(ret) || is_prefetch_end_) {
   } else if (is_ddl_mem_sstable) {
-    const bool is_co_sstable = sstable.is_co_sstable() || ObITable::TableType::DDL_MEM_CO_SSTABLE == sstable.get_key().table_type_;
+    const bool is_co_sstable = sstable.is_co_sstable() || sstable.is_ddl_mem_co_cg_sstable();
     const ObMicroBlockData &root_block = sstable_meta_hdl_.get_sstable_meta().get_root_info().get_block_data();
     if (ObMicroBlockData::DDL_BLOCK_TREE != root_block.type_ || nullptr == root_block.buf_) {
       ret = OB_ERR_UNEXPECTED;
diff --git a/src/storage/column_store/ob_column_store_util.h b/src/storage/column_store/ob_column_store_util.h
index f12f2318b3..dcce19b0d7 100644
--- a/src/storage/column_store/ob_column_store_util.h
+++ b/src/storage/column_store/ob_column_store_util.h
@@ -62,7 +62,7 @@ struct ObCSRange
   OB_INLINE ObCSRowId begin() const { return start_row_id_; }
   OB_INLINE ObCSRowId end() const { return end_row_id_; }
   OB_INLINE void reset() { start_row_id_ = OB_INVALID_CS_ROW_ID; end_row_id_ = OB_INVALID_CS_ROW_ID; }
-  OB_INLINE bool is_valid() const { return OB_INVALID_CS_ROW_ID != start_row_id_ && end_row_id_ >= start_row_id_; }
+  OB_INLINE bool is_valid() const { return OB_INVALID_CS_ROW_ID != start_row_id_ && end_row_id_ >= start_row_id_ && end_row_id_ >= 0; }
   OB_INLINE int64_t get_row_count() const { return end_row_id_ - start_row_id_ + 1; }
   int compare(const ObCSRowId idx) const
   {
diff --git a/src/storage/ddl/ob_tablet_ddl_kv.cpp b/src/storage/ddl/ob_tablet_ddl_kv.cpp
index 4e1d9544d4..5384bedbbf 100644
--- a/src/storage/ddl/ob_tablet_ddl_kv.cpp
+++ b/src/storage/ddl/ob_tablet_ddl_kv.cpp
@@ -872,7 +872,7 @@ int ObDDLMemtable::init_ddl_index_iterator(const blocksstable::ObStorageDatumUti
                                            blocksstable::ObDDLIndexBlockRowIterator *ddl_kv_index_iter)
 {
   int ret = OB_SUCCESS;
-  const bool is_co_sst = is_co_sstable();
+  const bool is_co_sst = is_co_sstable() || is_ddl_mem_co_cg_sstable();
   if (OB_ISNULL(datum_utils) || OB_UNLIKELY(!datum_utils->is_valid()) || OB_ISNULL(ddl_kv_index_iter)) {
     ret = OB_INVALID_ARGUMENT;
     LOG_WARN("invalid arguement", K(ret), KP(ddl_kv_index_iter), KPC(datum_utils));
diff --git a/src/storage/ob_i_table.h b/src/storage/ob_i_table.h
index c277462741..27f6bae58a 100644
--- a/src/storage/ob_i_table.h
+++ b/src/storage/ob_i_table.h
@@ -134,6 +134,7 @@ public:
     OB_INLINE bool is_major_sstable() const { return ObITable::is_major_sstable(table_type_) || ObITable::is_meta_major_sstable(table_type_); }
     OB_INLINE bool is_major_or_ddl_merge_sstable() const { return is_major_sstable() || ObITable::is_ddl_merge_sstable(table_type_); }
     OB_INLINE bool is_ddl_merge_sstable() const { return ObITable::is_ddl_merge_sstable(table_type_); }
+    OB_INLINE bool is_ddl_mem_co_cg_sstable() const { return ObITable::is_ddl_mem_co_cg_sstable(table_type_); }
     OB_INLINE bool is_meta_major_sstable() const { return ObITable::is_meta_major_sstable(table_type_); }
     OB_INLINE bool is_multi_version_table() const { return ObITable::is_multi_version_table(table_type_); }
     OB_INLINE bool is_ddl_sstable() const { return ObITable::is_ddl_sstable(table_type_); }
@@ -272,6 +273,7 @@ public:
   virtual bool is_ddl_dump_sstable() const { return is_ddl_dump_sstable(key_.table_type_); }
   virtual bool is_ddl_mem_sstable() const { return is_ddl_mem_sstable(key_.table_type_); }
   virtual bool is_ddl_merge_sstable() const { return is_ddl_merge_sstable(key_.table_type_); }
+  virtual bool is_ddl_mem_co_cg_sstable() const { return is_ddl_mem_co_cg_sstable(key_.table_type_); }
   virtual bool is_remote_logical_minor_sstable() const { return is_remote_logical_minor_sstable(key_.table_type_); }
   virtual bool is_empty() const = 0;
   virtual bool no_data_to_read() const { return is_empty(); }
@@ -417,6 +419,11 @@ public:
     return ObITable::TableType::DDL_MERGE_CO_SSTABLE == table_type
       || ObITable::TableType::DDL_MERGE_CG_SSTABLE == table_type;
   }
+  static bool is_ddl_mem_co_cg_sstable(const TableType table_type)
+  {
+    return ObITable::TableType::DDL_MEM_CG_SSTABLE == table_type
+      || ObITable::TableType::DDL_MEM_CO_SSTABLE == table_type;
+  }
   static bool is_table_with_scn_range(const TableType table_type)
   {
     return is_multi_version_table(table_type) || is_meta_major_sstable(table_type);