diff --git a/src/storage/CMakeLists.txt b/src/storage/CMakeLists.txt
index ca0122f590..32376ce743 100755
--- a/src/storage/CMakeLists.txt
+++ b/src/storage/CMakeLists.txt
@@ -504,6 +504,7 @@ ob_set_subtarget(ob_storage compaction
   compaction/ob_tenant_freeze_info_mgr.cpp
   compaction/ob_tenant_tablet_scheduler.cpp
   compaction/ob_schedule_dag_func.cpp
+  compaction/ob_extra_medium_info.cpp
   compaction/ob_medium_compaction_func.cpp
   compaction/ob_medium_compaction_mgr.cpp
   compaction/ob_medium_compaction_info.cpp
diff --git a/src/storage/compaction/ob_extra_medium_info.cpp b/src/storage/compaction/ob_extra_medium_info.cpp
new file mode 100644
index 0000000000..157960e995
--- /dev/null
+++ b/src/storage/compaction/ob_extra_medium_info.cpp
@@ -0,0 +1,94 @@
+/**
+ * Copyright (c) 2021 OceanBase
+ * OceanBase CE is licensed under Mulan PubL v2.
+ * You can use this software according to the terms and conditions of the Mulan PubL v2.
+ * You may obtain a copy of Mulan PubL v2 at:
+ *          http://license.coscl.org.cn/MulanPubL-2.0
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PubL v2 for more details.
+ */
+
+#include "storage/compaction/ob_extra_medium_info.h"
+#include "lib/oblog/ob_log_module.h"
+#include "lib/utility/ob_macro_utils.h"
+
+using namespace oceanbase::common;
+
+namespace oceanbase
+{
+namespace compaction
+{
+ObExtraMediumInfo::ObExtraMediumInfo()
+  : compat_(MEDIUM_LIST_VERSION),
+    last_compaction_type_(0),
+    wait_check_flag_(0),
+    reserved_(0),
+    last_medium_scn_(0)
+{
+}
+
+ObExtraMediumInfo::ObExtraMediumInfo(const ObExtraMediumInfo &other)
+{
+  if (this != &other) {
+    compat_ = other.compat_;
+    last_compaction_type_ = other.last_compaction_type_;
+    wait_check_flag_ = other.wait_check_flag_;
+    reserved_ = other.reserved_;
+    last_medium_scn_ = other.last_medium_scn_;
+  }
+}
+
+ObExtraMediumInfo &ObExtraMediumInfo::operator=(const ObExtraMediumInfo &other)
+{
+  if (this != &other) {
+    compat_ = other.compat_;
+    last_compaction_type_ = other.last_compaction_type_;
+    wait_check_flag_ = other.wait_check_flag_;
+    reserved_ = other.reserved_;
+    last_medium_scn_ = other.last_medium_scn_;
+  }
+  return *this;
+}
+
+void ObExtraMediumInfo::reset()
+{
+  compat_ = MEDIUM_LIST_VERSION;
+  last_compaction_type_ = 0;
+  wait_check_flag_ = 0;
+  reserved_ = 0;
+  last_medium_scn_ = 0;
+}
+
+int ObExtraMediumInfo::serialize(char *buf, const int64_t buf_len, int64_t &pos) const
+{
+  int ret = OB_SUCCESS;
+  LST_DO_CODE(OB_UNIS_ENCODE,
+      info_,
+      last_medium_scn_);
+
+  return ret;
+}
+
+int ObExtraMediumInfo::deserialize(const char *buf, const int64_t data_len, int64_t &pos)
+{
+  int ret = OB_SUCCESS;
+  LST_DO_CODE(OB_UNIS_DECODE,
+      info_,
+      last_medium_scn_);
+
+  return ret;
+}
+
+int64_t ObExtraMediumInfo::get_serialize_size() const
+{
+  int64_t len = 0;
+  LST_DO_CODE(OB_UNIS_ADD_LEN,
+      info_,
+      last_medium_scn_);
+
+  return len;
+}
+} // namespace compaction
+} // namespace oceanbase
\ No newline at end of file
diff --git a/src/storage/compaction/ob_extra_medium_info.h b/src/storage/compaction/ob_extra_medium_info.h
new file mode 100644
index 0000000000..dede4b9e83
--- /dev/null
+++ b/src/storage/compaction/ob_extra_medium_info.h
@@ -0,0 +1,62 @@
+/**
+ * Copyright (c) 2021 OceanBase
+ * OceanBase CE is licensed under Mulan PubL v2.
+ * You can use this software according to the terms and conditions of the Mulan PubL v2.
+ * You may obtain a copy of Mulan PubL v2 at:
+ *          http://license.coscl.org.cn/MulanPubL-2.0
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PubL v2 for more details.
+ */
+
+#ifndef OCEANBASE_COMPACTION_OB_EXTRA_MEDIUM_INFO
+#define OCEANBASE_COMPACTION_OB_EXTRA_MEDIUM_INFO
+
+#include <stdint.h>
+#include "lib/utility/ob_print_utils.h"
+
+namespace oceanbase
+{
+namespace compaction
+{
+class ObExtraMediumInfo
+{
+public:
+  ObExtraMediumInfo();
+  ~ObExtraMediumInfo() = default;
+  ObExtraMediumInfo(const ObExtraMediumInfo &other);
+  ObExtraMediumInfo &operator=(const ObExtraMediumInfo &other);
+public:
+  void reset();
+
+  int serialize(char *buf, const int64_t buf_len, int64_t &pos) const;
+  int deserialize(const char *buf, const int64_t data_len, int64_t &pos);
+  int64_t get_serialize_size() const;
+
+  TO_STRING_KV(K_(info),
+               K_(compat),
+               K_(last_compaction_type),
+               K_(wait_check_flag),
+               K_(last_medium_scn));
+public:
+  static constexpr int64_t MEDIUM_LIST_VERSION = 1;
+  static constexpr int32_t MEDIUM_LIST_INFO_RESERVED_BITS = 51;
+public:
+  union
+  {
+    uint64_t info_;
+    struct
+    {
+      uint64_t compat_                  : 8;
+      uint64_t last_compaction_type_    : 4; // check inner_table when last_compaction is major
+      uint64_t wait_check_flag_         : 1; // true: need check finish, false: no need check
+      uint64_t reserved_                : MEDIUM_LIST_INFO_RESERVED_BITS;
+    };
+  };
+  int64_t last_medium_scn_;
+};
+} // namespace compaction
+} // namespace oceanbase
+
+#endif // OCEANBASE_COMPACTION_OB_EXTRA_MEDIUM_INFO
diff --git a/src/storage/compaction/ob_medium_compaction_mgr.cpp b/src/storage/compaction/ob_medium_compaction_mgr.cpp
index 84f4d477bc..dfa7d009b2 100644
--- a/src/storage/compaction/ob_medium_compaction_mgr.cpp
+++ b/src/storage/compaction/ob_medium_compaction_mgr.cpp
@@ -24,6 +24,7 @@
 namespace oceanbase
 {
 using namespace storage;
+using namespace common;
 
 namespace compaction
 {
@@ -404,11 +405,8 @@ int ObTabletMediumCompactionInfoRecorder::submit_log(
 ObMediumCompactionInfoList::ObMediumCompactionInfoList()
   : is_inited_(false),
     allocator_(nullptr),
-    compat_(MEDIUM_LIST_VERSION),
-    last_compaction_type_(0),
-    wait_check_flag_(0),
-    reserved_(0),
-    last_medium_scn_(0)
+    extra_info_(),
+    medium_info_list_()
 {
 }
 
@@ -424,7 +422,6 @@ int ObMediumCompactionInfoList::init(common::ObIAllocator &allocator)
     ret = OB_INIT_TWICE;
     LOG_WARN("init twice", K(ret));
   } else {
-    compat_ = MEDIUM_LIST_VERSION;
     allocator_ = &allocator;
     is_inited_ = true;
   }
@@ -445,7 +442,6 @@ int ObMediumCompactionInfoList::init(
   } else {
     allocator_ = &allocator;
     set_basic_info(*input_list);
-    compat_ = MEDIUM_LIST_VERSION;
     is_inited_ = true;
   }
   return ret;
@@ -453,7 +449,7 @@ int ObMediumCompactionInfoList::init(
 
 int ObMediumCompactionInfoList::init(
     common::ObIAllocator &allocator,
-    const ObTaletExtraMediumInfo &extra_medium_info,
+    const ObExtraMediumInfo &extra_medium_info,
     const ObTabletDumpedMediumInfo &medium_info_list)
 {
   int ret = OB_SUCCESS;
@@ -497,10 +493,7 @@ int ObMediumCompactionInfoList::init(
     if (OB_FAIL(ret)) {
       reset();
     } else {
-      compat_ = MEDIUM_LIST_VERSION;
-      last_compaction_type_ = extra_medium_info.last_compaction_type_;
-      last_medium_scn_ = extra_medium_info.last_medium_scn_;
-      wait_check_flag_ = extra_medium_info.wait_check_flag_;
+      extra_info_ = extra_medium_info;
       is_inited_ = true;
     }
   }
@@ -522,10 +515,9 @@ void ObMediumCompactionInfoList::reset()
   if (OB_NOT_NULL(allocator_)) {
     reset_list();
   }
-  is_inited_ = false;
-  info_ = 0;
-  last_medium_scn_ = 0;
+  extra_info_.reset();
   allocator_ = nullptr;
+  is_inited_ = false;
 }
 
 int ObMediumCompactionInfoList::serialize(char *buf, const int64_t buf_len, int64_t &pos) const
@@ -539,12 +531,10 @@ int ObMediumCompactionInfoList::serialize(char *buf, const int64_t buf_len, int6
   } else if (OB_UNLIKELY(!is_valid())) {
     ret = OB_ERR_UNEXPECTED;
     LOG_WARN("medium info list is invalid", K(ret), KPC(this));
-  } else if (OB_FAIL(serialization::encode_vi64(buf, buf_len, new_pos, info_))) {
-    STORAGE_LOG(WARN, "failed to serialize info", K(ret), K(buf_len), K(pos));
-  } else if (OB_FAIL(serialization::encode_vi64(buf, buf_len, new_pos, last_medium_scn_))) {
-    STORAGE_LOG(WARN, "failed to serialize wait_check_medium_scn", K(ret), K(buf_len), K(pos));
+  } else if (OB_FAIL(extra_info_.serialize(buf, buf_len, new_pos))) {
+    LOG_WARN("failed to serialize extra info", K(ret), K(buf_len), K(pos));
   } else if (OB_FAIL(serialization::encode_vi64(buf, buf_len, new_pos, medium_info_list_.get_size()))) {
-    LOG_WARN("failed to serialize medium status", K(ret), K(buf_len));
+    LOG_WARN("failed to serialize medium info list count", K(ret), K(buf_len));
   } else {
     DLIST_FOREACH_X(info, medium_info_list_, OB_SUCC(ret)) {
       if (OB_FAIL(static_cast<const ObMediumCompactionInfo *>(info)->serialize(buf, buf_len, new_pos))) {
@@ -569,6 +559,7 @@ int ObMediumCompactionInfoList::deserialize(
   int ret = OB_SUCCESS;
   int64_t new_pos = pos;
   int64_t deserialize_info = 0;
+  int64_t last_medium_scn = 0;
   int64_t list_count = 0;
   if (IS_INIT) {
     ret = OB_INIT_TWICE;
@@ -577,7 +568,7 @@ int ObMediumCompactionInfoList::deserialize(
     ret = OB_INVALID_ARGUMENT;
     LOG_WARN("invalid args", K(ret), K(buf), K(data_len), K(pos));
   } else if (OB_FAIL(serialization::decode_vi64(buf, data_len, new_pos, &deserialize_info))) {
-    LOG_WARN("failed to deserialize cur medium snapshot", K(ret), K(data_len));
+    LOG_WARN("failed to deserialize info", K(ret), K(data_len));
   } else if (0 == deserialize_info) {
     if (OB_FAIL(serialization::decode_vi64(buf, data_len, new_pos, &list_count))) {
       LOG_WARN("failed to deserialize list count", K(ret), K(data_len));
@@ -585,10 +576,11 @@ int ObMediumCompactionInfoList::deserialize(
       ret = OB_ERR_UNEXPECTED;
       LOG_WARN("list count should be zero in old version medium list", K(ret), K(list_count));
     }
-  } else if (FALSE_IT(info_ = deserialize_info)) {
+  } else if (FALSE_IT(extra_info_.info_ = deserialize_info)) {
   } else if (FALSE_IT(allocator_ = &allocator)) { // set allocator to call reset() when deserialize failed
-  } else if (OB_FAIL(serialization::decode_vi64(buf, data_len, new_pos, &last_medium_scn_))) {
-    LOG_WARN("failed to deserialize wait_check_medium_scn", K(ret), K(data_len));
+  } else if (OB_FAIL(serialization::decode_vi64(buf, data_len, new_pos, &last_medium_scn))) {
+    LOG_WARN("failed to deserialize last medium scn", K(ret), K(data_len));
+  } else if (FALSE_IT(extra_info_.last_medium_scn_ = last_medium_scn)) {
   } else if (OB_FAIL(serialization::decode_vi64(buf, data_len, new_pos, &list_count))) {
     LOG_WARN("failed to deserialize list count", K(ret), K(data_len));
   } else if (OB_UNLIKELY(list_count < 0)) {
@@ -624,7 +616,7 @@ int ObMediumCompactionInfoList::deserialize(
     ret = OB_ERR_UNEXPECTED;
     LOG_WARN("medium info list is invalid", K(ret), KPC(this));
   } else {
-    compat_ = MEDIUM_LIST_VERSION;
+    extra_info_.compat_ = ObExtraMediumInfo::MEDIUM_LIST_VERSION;
     is_inited_ = true;
     pos = new_pos;
   }
@@ -634,8 +626,7 @@ int ObMediumCompactionInfoList::deserialize(
 int64_t ObMediumCompactionInfoList::get_serialize_size() const
 {
   int64_t len = 0;
-  len += serialization::encoded_length_vi64(info_);
-  len += serialization::encoded_length_vi64(last_medium_scn_);
+  len += extra_info_.get_serialize_size();
   len += serialization::encoded_length_vi64(medium_info_list_.get_size());
   DLIST_FOREACH_NORET(info, medium_info_list_){
     len += static_cast<const ObMediumCompactionInfo *>(info)->get_serialize_size();
@@ -650,7 +641,7 @@ void ObMediumCompactionInfoList::gene_info(
     // do nothing
   } else {
     J_OBJ_START();
-    J_KV("size", size(), K_(last_compaction_type), K_(wait_check_flag), K_(last_medium_scn));
+    J_KV(K_(extra_info), "size", size());
     J_COMMA();
     BUF_PRINTF("info_list");
     J_COLON();
diff --git a/src/storage/compaction/ob_medium_compaction_mgr.h b/src/storage/compaction/ob_medium_compaction_mgr.h
index 59a05899b6..bcad827d33 100644
--- a/src/storage/compaction/ob_medium_compaction_mgr.h
+++ b/src/storage/compaction/ob_medium_compaction_mgr.h
@@ -19,13 +19,13 @@
 #include "storage/meta_mem/ob_tablet_handle.h"
 #include "storage/compaction/ob_partition_merge_policy.h"
 #include "storage/compaction/ob_medium_compaction_info.h"
+#include "storage/compaction/ob_extra_medium_info.h"
 
 namespace oceanbase
 {
 namespace storage
 {
 class ObTablet;
-class ObTaletExtraMediumInfo;
 class ObTabletDumpedMediumInfo;
 }
 namespace compaction
@@ -100,7 +100,7 @@ public:
 
   int init(
       common::ObIAllocator &allocator,
-      const ObTaletExtraMediumInfo &extra_medium_info,
+      const ObExtraMediumInfo &extra_medium_info,
       const ObTabletDumpedMediumInfo &medium_info_list);
 
   void reset();
@@ -112,8 +112,8 @@ public:
     return inner_is_valid();
   }
   OB_INLINE const MediumInfoList &get_list() const { return medium_info_list_; }
-  OB_INLINE int64_t get_wait_check_medium_scn() const { return wait_check_flag_ ? last_medium_scn_ : 0; }
-  OB_INLINE bool need_check_finish() const { return wait_check_flag_; }
+  OB_INLINE int64_t get_wait_check_medium_scn() const { return extra_info_.wait_check_flag_ ? extra_info_.last_medium_scn_ : 0; }
+  OB_INLINE bool need_check_finish() const { return extra_info_.wait_check_flag_; }
   // check status on serialized medium list
   OB_INLINE bool could_schedule_next_round() const
   {
@@ -122,15 +122,15 @@ public:
   const ObMediumCompactionInfo *get_next_schedule_medium_info(const int64_t last_major_snapshot) const;
   OB_INLINE ObMediumCompactionInfo::ObCompactionType get_last_compaction_type() const
   {
-    return (ObMediumCompactionInfo::ObCompactionType)last_compaction_type_;
+    return static_cast<ObMediumCompactionInfo::ObCompactionType>(extra_info_.last_compaction_type_);
   }
   OB_INLINE int64_t get_last_compaction_scn() const
   {
-    return last_medium_scn_;
+    return extra_info_.last_medium_scn_;
   }
   OB_INLINE uint64_t get_union_info() const
   {
-    return info_;
+    return extra_info_.info_;
   }
 
   // serialize & deserialize
@@ -147,42 +147,26 @@ public:
     const ObMediumCompactionInfo &medium_info,
     const ObITable *last_major_sstable,
     const bool force_check);
-  TO_STRING_KV(K_(is_inited), K_(info), K_(last_compaction_type), K_(wait_check_flag), K_(last_medium_scn),
-      "list_size", size(), K_(medium_info_list));
+  TO_STRING_KV(K_(is_inited), K_(extra_info), "list_size", size(), K_(medium_info_list));
 
 private:
   void reset_list();
   OB_INLINE bool inner_is_valid() const
   {
-    return last_compaction_type_ < ObMediumCompactionInfo::COMPACTION_TYPE_MAX
-        && last_medium_scn_ >= 0 && size() >= 0;
+    return extra_info_.last_compaction_type_ < ObMediumCompactionInfo::COMPACTION_TYPE_MAX
+        && extra_info_.last_medium_scn_ >= 0 && size() >= 0;
   }
 
   OB_INLINE void set_basic_info(const ObMediumCompactionInfoList &input_list)
   {
-    last_compaction_type_ = input_list.last_compaction_type_;
-    last_medium_scn_ = input_list.last_medium_scn_;
-    wait_check_flag_ = input_list.wait_check_flag_;
+    extra_info_ = input_list.extra_info_;
   }
-private:
-  static const int64_t MEDIUM_LIST_VERSION = 1;
-  static const int32_t MEDIUM_LIST_INFO_RESERVED_BITS = 51;
 
 private:
   bool is_inited_;
   common::ObIAllocator *allocator_;
 
-  // need serialize
-  union {
-    uint64_t info_;
-    struct {
-      uint64_t compat_                  : 8;
-      uint64_t last_compaction_type_    : 4; // check inner_table when last_compaction is major
-      uint64_t wait_check_flag_         : 1; // true: need check finish, false: don't need check
-      uint64_t reserved_                : MEDIUM_LIST_INFO_RESERVED_BITS;
-    };
-  };
-  int64_t last_medium_scn_; // record last finish medium_scn
+  ObExtraMediumInfo extra_info_;
 
   MediumInfoList medium_info_list_; // need for compat, will not store any MediumCompactionInfo after 4.2
 };
diff --git a/src/storage/tablet/ob_tablet.cpp b/src/storage/tablet/ob_tablet.cpp
index e3af278d85..5b601b2b30 100755
--- a/src/storage/tablet/ob_tablet.cpp
+++ b/src/storage/tablet/ob_tablet.cpp
@@ -31,16 +31,18 @@
 #include "share/schema/ob_table_schema.h"
 #include "share/schema/ob_tenant_schema_service.h"
 #include "share/ob_tablet_autoincrement_service.h"
-#include "storage/access/ob_dml_param.h"
 #include "storage/ob_dml_running_ctx.h"
 #include "storage/ob_i_store.h"
 #include "storage/ob_i_table.h"
 #include "storage/ob_row_reshape.h"
 #include "storage/ob_sync_tablet_seq_clog.h"
 #include "storage/ob_storage_schema.h"
+#include "storage/ob_tenant_tablet_stat_mgr.h"
+#include "storage/access/ob_dml_param.h"
 #include "storage/blocksstable/ob_sstable.h"
 #include "storage/blocksstable/ob_sstable_sec_meta_iterator.h"
 #include "storage/blocksstable/ob_storage_cache_suite.h"
+#include "storage/compaction/ob_extra_medium_info.h"
 #include "storage/compaction/ob_tenant_freeze_info_mgr.h"
 #include "storage/compaction/ob_tenant_tablet_scheduler.h"
 #include "storage/memtable/ob_memtable.h"
@@ -60,15 +62,13 @@
 #include "storage/tablet/ob_tablet_create_delete_helper.h"
 #include "storage/tablet/ob_tablet_memtable_mgr.h"
 #include "storage/tablet/ob_tablet_ddl_info.h"
+#include "storage/tablet/ob_tablet_medium_info_reader.h"
 #include "storage/tablet/ob_tablet_mds_node_dump_operator.h"
 #include "storage/tablet/ob_tablet_create_delete_mds_user_data.h"
 #include "storage/tablet/ob_tablet_binding_mds_user_data.h"
 #include "storage/tx/ob_trans_part_ctx.h"
 #include "storage/tx/ob_trans_service.h"
 #include "storage/tx_storage/ob_ls_service.h"
-#include "storage/ob_tenant_tablet_stat_mgr.h"
-#include "storage/blocksstable/ob_storage_cache_suite.h"
-#include "storage/tablet/ob_tablet_medium_info_reader.h"
 
 namespace oceanbase
 {
@@ -5506,7 +5506,7 @@ int ObTablet::set_initial_state(const bool initial_state)
 int ObTablet::load_medium_info_list(
     common::ObArenaAllocator &allocator,
     const ObTabletComplexAddr<oceanbase::storage::ObTabletDumpedMediumInfo> &complex_addr,
-    const ObTaletExtraMediumInfo &extra_info,
+    const compaction::ObExtraMediumInfo &extra_info,
     compaction::ObMediumCompactionInfoList &medium_info_list)
 {
   int ret = OB_SUCCESS;
diff --git a/src/storage/tablet/ob_tablet.h b/src/storage/tablet/ob_tablet.h
index e9b2b7513e..a7e7b8f41d 100755
--- a/src/storage/tablet/ob_tablet.h
+++ b/src/storage/tablet/ob_tablet.h
@@ -70,6 +70,12 @@ namespace blocksstable
 {
 class ObSSTable;
 }
+
+namespace compaction
+{
+class ObExtraMediumInfo;
+}
+
 namespace transaction
 {
 class ObTransID;
@@ -631,7 +637,7 @@ private:
   static int load_medium_info_list(
       common::ObArenaAllocator &allocator,
       const ObTabletComplexAddr<oceanbase::storage::ObTabletDumpedMediumInfo> &complex_addr,
-      const ObTaletExtraMediumInfo &extra_info,
+      const compaction::ObExtraMediumInfo &extra_info,
       compaction::ObMediumCompactionInfoList &medium_info_list);
   int set_initial_state(const bool initial_state);
 
diff --git a/src/storage/tablet/ob_tablet_full_medium_info.cpp b/src/storage/tablet/ob_tablet_full_medium_info.cpp
index 1a7bdeaf2d..d87f6e0c3d 100644
--- a/src/storage/tablet/ob_tablet_full_medium_info.cpp
+++ b/src/storage/tablet/ob_tablet_full_medium_info.cpp
@@ -22,55 +22,6 @@ namespace oceanbase
 {
 namespace storage
 {
-ObTaletExtraMediumInfo::ObTaletExtraMediumInfo()
-  : compat_(MEDIUM_LIST_VERSION),
-    last_compaction_type_(0),
-    wait_check_flag_(0),
-    reserved_(0),
-    last_medium_scn_(0)
-{
-}
-
-void ObTaletExtraMediumInfo::reset()
-{
-  compat_ = MEDIUM_LIST_VERSION;
-  last_compaction_type_ = 0;
-  wait_check_flag_ = 0;
-  reserved_ = 0;
-  last_medium_scn_ = 0;
-}
-
-int ObTaletExtraMediumInfo::serialize(char *buf, const int64_t buf_len, int64_t &pos) const
-{
-  int ret = OB_SUCCESS;
-  LST_DO_CODE(OB_UNIS_ENCODE,
-      info_,
-      last_medium_scn_);
-
-  return ret;
-}
-
-int ObTaletExtraMediumInfo::deserialize(const char *buf, const int64_t data_len, int64_t &pos)
-{
-  int ret = OB_SUCCESS;
-  LST_DO_CODE(OB_UNIS_DECODE,
-      info_,
-      last_medium_scn_);
-
-  return ret;
-}
-
-int64_t ObTaletExtraMediumInfo::get_serialize_size() const
-{
-  int64_t len = 0;
-  LST_DO_CODE(OB_UNIS_ADD_LEN,
-      info_,
-      last_medium_scn_);
-
-  return len;
-}
-
-
 ObTabletFullMediumInfo::ObTabletFullMediumInfo()
   : extra_medium_info_(),
     medium_info_list_()
diff --git a/src/storage/tablet/ob_tablet_full_medium_info.h b/src/storage/tablet/ob_tablet_full_medium_info.h
index 23e84b4a7e..cb3ce09822 100644
--- a/src/storage/tablet/ob_tablet_full_medium_info.h
+++ b/src/storage/tablet/ob_tablet_full_medium_info.h
@@ -16,6 +16,7 @@
 #include <stdint.h>
 #include "lib/utility/ob_print_utils.h"
 #include "storage/compaction/ob_compaction_util.h"
+#include "storage/compaction/ob_extra_medium_info.h"
 #include "storage/tablet/ob_tablet_dumped_medium_info.h"
 
 namespace oceanbase
@@ -27,41 +28,6 @@ class ObIAllocator;
 
 namespace storage
 {
-class ObTaletExtraMediumInfo
-{
-public:
-  ObTaletExtraMediumInfo();
-  ~ObTaletExtraMediumInfo() = default;
-public:
-  void reset();
-
-  int serialize(char *buf, const int64_t buf_len, int64_t &pos) const;
-  int deserialize(const char *buf, const int64_t data_len, int64_t &pos);
-  int64_t get_serialize_size() const;
-
-  TO_STRING_KV(K_(info),
-               K_(compat),
-               K_(last_compaction_type),
-               K_(wait_check_flag),
-               K_(last_medium_scn));
-private:
-  static const int64_t MEDIUM_LIST_VERSION = 1;
-  static const int32_t MEDIUM_LIST_INFO_RESERVED_BITS = 51;
-public:
-  union
-  {
-    uint64_t info_;
-    struct
-    {
-      uint64_t compat_                  : 8;
-      uint64_t last_compaction_type_    : 4; // check inner_table when last_compaction is major
-      uint64_t wait_check_flag_         : 1; // true: need check finish, false: don't need check
-      uint64_t reserved_                : MEDIUM_LIST_INFO_RESERVED_BITS;
-    };
-  };
-  int64_t last_medium_scn_;
-};
-
 class ObTabletFullMediumInfo
 {
 public:
@@ -79,7 +45,7 @@ public:
 
   TO_STRING_KV(K_(extra_medium_info), K_(medium_info_list));
 public:
-  ObTaletExtraMediumInfo extra_medium_info_;
+  compaction::ObExtraMediumInfo extra_medium_info_;
   ObTabletDumpedMediumInfo medium_info_list_;
 };
 } // namespace storage
diff --git a/src/storage/tablet/ob_tablet_mds_data.cpp b/src/storage/tablet/ob_tablet_mds_data.cpp
index 693a21ae62..849bedd326 100644
--- a/src/storage/tablet/ob_tablet_mds_data.cpp
+++ b/src/storage/tablet/ob_tablet_mds_data.cpp
@@ -17,6 +17,7 @@
 #include "lib/utility/ob_macro_utils.h"
 #include "storage/blocksstable/ob_storage_cache_suite.h"
 #include "storage/compaction/ob_medium_compaction_mgr.h"
+#include "storage/compaction/ob_extra_medium_info.h"
 #include "storage/tablet/ob_tablet_full_memory_mds_data.h"
 #include "storage/tablet/ob_tablet_obj_load_helper.h"
 #include "ob_i_tablet_mds_interface.h"
@@ -529,7 +530,7 @@ int ObTabletMdsData::do_init(
 int ObTabletMdsData::init_medium_info_list(
     common::ObIAllocator &allocator,
     const ObTabletDumpedMediumInfo *old_medium_info_list,
-    const ObTaletExtraMediumInfo &old_extra_medium_info,
+    const compaction::ObExtraMediumInfo &old_extra_medium_info,
     const int64_t finish_medium_scn,
     const ObMergeType merge_type)
 {
@@ -570,7 +571,7 @@ int ObTabletMdsData::init_medium_info_list(
     common::ObIAllocator &allocator,
     const ObTabletDumpedMediumInfo *old_medium_info_list,
     const ObTabletFullMediumInfo &full_memory_medium_info_list,
-    const ObTaletExtraMediumInfo &old_extra_medium_info,
+    const compaction::ObExtraMediumInfo &old_extra_medium_info,
     const int64_t finish_medium_scn)
 {
   int ret = OB_SUCCESS;
@@ -625,7 +626,7 @@ int ObTabletMdsData::init_medium_info_list(
 int ObTabletMdsData::init_with_update_medium_info(
     common::ObIAllocator &allocator,
     const ObTabletDumpedMediumInfo *old_medium_info_list,
-    const ObTaletExtraMediumInfo &old_extra_medium_info)
+    const compaction::ObExtraMediumInfo &old_extra_medium_info)
 {
   int ret = OB_SUCCESS;
   const int64_t finish_medium_scn = old_extra_medium_info.last_medium_scn_;
diff --git a/src/storage/tablet/ob_tablet_mds_data.h b/src/storage/tablet/ob_tablet_mds_data.h
index 2a5d5c4f8a..ce70144333 100644
--- a/src/storage/tablet/ob_tablet_mds_data.h
+++ b/src/storage/tablet/ob_tablet_mds_data.h
@@ -35,6 +35,7 @@ namespace compaction
 class ObMediumCompactionInfoKey;
 class ObMediumCompactionInfo;
 class ObMediumCompactionInfoList;
+class ObExtraMediumInfo;
 }
 
 namespace storage
@@ -168,19 +169,19 @@ private:
   int init_medium_info_list(
       common::ObIAllocator &allocator,
       const ObTabletDumpedMediumInfo *old_medium_info_list,
-      const ObTaletExtraMediumInfo &old_extra_medium_info,
+      const compaction::ObExtraMediumInfo &old_extra_medium_info,
       const int64_t finish_medium_scn = 0,
       const ObMergeType merge_type = ObMergeType::MERGE_TYPE_MAX);
   int init_medium_info_list(
       common::ObIAllocator &allocator,
       const ObTabletDumpedMediumInfo *old_medium_info_list,
       const ObTabletFullMediumInfo &full_memory_medium_info_list,
-      const ObTaletExtraMediumInfo &old_extra_medium_info,
+      const compaction::ObExtraMediumInfo &old_extra_medium_info,
       const int64_t finish_medium_scn);
   int init_with_update_medium_info(
       common::ObIAllocator &allocator,
       const ObTabletDumpedMediumInfo *old_medium_info_list,
-      const ObTaletExtraMediumInfo &old_extra_medium_info);
+      const compaction::ObExtraMediumInfo &old_extra_medium_info);
   static int fuse_mds_dump_node(
       common::ObIAllocator &allocator,
       const ObTabletComplexAddr<mds::MdsDumpKV> &mds_table_data,
@@ -226,7 +227,7 @@ public:
   ObTabletMdsDumpStruct tablet_status_;
   ObTabletMdsDumpStruct aux_tablet_info_;
 
-  ObTaletExtraMediumInfo extra_medium_info_;
+  compaction::ObExtraMediumInfo extra_medium_info_;
   ObTabletComplexAddr<ObTabletDumpedMediumInfo> medium_info_list_;
 
   ObTabletComplexAddr<share::ObTabletAutoincSeq> auto_inc_seq_;
diff --git a/src/storage/tablet/ob_tablet_persister.h b/src/storage/tablet/ob_tablet_persister.h
index 52bfa13614..64d22fa9a6 100644
--- a/src/storage/tablet/ob_tablet_persister.h
+++ b/src/storage/tablet/ob_tablet_persister.h
@@ -14,6 +14,7 @@
 #define OCEANBASE_STORAGE_OB_TABLET_PERSIST_H_
 
 #include "lib/allocator/page_arena.h"
+#include "storage/compaction/ob_extra_medium_info.h"
 #include "storage/meta_mem/ob_tenant_meta_mem_mgr.h"
 #include "storage/tablet/ob_tablet.h"
 #include "storage/blockstore/ob_shared_block_reader_writer.h"
@@ -57,7 +58,7 @@ public:
   ObMetaDiskAddr tablet_status_committed_kv_addr_;
   ObMetaDiskAddr aux_tablet_info_uncommitted_kv_addr_;
   ObMetaDiskAddr aux_tablet_info_committed_kv_addr_;
-  ObTaletExtraMediumInfo extra_medium_info_;
+  compaction::ObExtraMediumInfo extra_medium_info_;
   ObMetaDiskAddr medium_info_list_addr_;
   ObMetaDiskAddr auto_inc_seq_addr_;
   ObTabletCreateDeleteMdsUserData tablet_status_cache_;