diff --git a/src/storage/lob/ob_lob_data_reader.cpp b/src/storage/lob/ob_lob_data_reader.cpp
index c64391c01f..91043cdb28 100644
--- a/src/storage/lob/ob_lob_data_reader.cpp
+++ b/src/storage/lob/ob_lob_data_reader.cpp
@@ -23,7 +23,8 @@ namespace storage
 {
 
 ObLobDataReader::ObLobDataReader()
-  : is_inited_(false), tablet_id_(), access_ctx_(nullptr), allocator_(ObModIds::OB_LOB_READER)
+  : is_inited_(false), tablet_id_(), access_ctx_(nullptr),
+    allocator_(ObModIds::OB_LOB_READER, OB_MALLOC_NORMAL_BLOCK_SIZE, MTL_ID())
 {
 }