diff --git a/src/storage/access/ob_table_access_context.cpp b/src/storage/access/ob_table_access_context.cpp
index 1082909a0..96bd38f18 100644
--- a/src/storage/access/ob_table_access_context.cpp
+++ b/src/storage/access/ob_table_access_context.cpp
@@ -66,11 +66,12 @@ ObTableAccessContext::ObTableAccessContext()
     out_cnt_(0),
     trans_version_range_(),
     range_array_pos_(nullptr),
-    merge_log_ts_(INT_MAX),
+    merge_scn_(),
     lob_locator_helper_(nullptr),
     iter_pool_(nullptr),
     block_row_store_(nullptr)
 {
+  merge_scn_.set_max();
 }
 
 ObTableAccessContext::~ObTableAccessContext()
diff --git a/src/storage/access/ob_table_access_context.h b/src/storage/access/ob_table_access_context.h
index af00eb904..374366084 100644
--- a/src/storage/access/ob_table_access_context.h
+++ b/src/storage/access/ob_table_access_context.h
@@ -16,6 +16,7 @@
 #include "ob_table_access_param.h"
 #include "storage/lob/ob_lob_locator.h"
 #include "storage/tx/ob_defensive_check_mgr.h"
+#include "logservice/palf/scn.h"
 
 namespace oceanbase
 {
@@ -101,7 +102,7 @@ struct ObTableAccessContext
     KP_(table_scan_stat),
     K_(out_cnt),
     K_(trans_version_range),
-    K_(merge_log_ts),
+    K_(merge_scn),
     K_(lob_locator_helper),
     KP_(iter_pool),
     KP_(block_row_store));
@@ -132,7 +133,7 @@ public:
   int64_t out_cnt_;
   common::ObVersionRange trans_version_range_;
   const common::ObSEArray<int64_t, 4, common::ModulePageAllocator> *range_array_pos_;
-  int64_t merge_log_ts_;
+  palf::SCN merge_scn_;
   ObLobLocatorHelper *lob_locator_helper_;
   ObStoreRowIterPool *iter_pool_;
   ObBlockRowStore *block_row_store_;
diff --git a/src/storage/blocksstable/ob_micro_block_row_scanner.cpp b/src/storage/blocksstable/ob_micro_block_row_scanner.cpp
index 353f4d1cd..15ca49443 100644
--- a/src/storage/blocksstable/ob_micro_block_row_scanner.cpp
+++ b/src/storage/blocksstable/ob_micro_block_row_scanner.cpp
@@ -1995,12 +1995,10 @@ int ObMultiVersionMicroBlockMinorMergeRowScanner::get_trans_state(
   int ret = OB_SUCCESS;
   //get trans status & committed_trans_version_
   SCN scn_commit_trans_version = SCN::max_scn();
-  SCN merge_scn;
-  merge_scn.convert_for_lsn_allocator(context_->merge_log_ts_);
   auto &tx_table_guard = context_->store_ctx_->mvcc_acc_ctx_.get_tx_table_guard();
   int64_t read_epoch = tx_table_guard.epoch();;
   if (OB_FAIL(tx_table_guard.get_tx_table()->get_tx_state_with_scn(
-      trans_id, merge_scn, read_epoch, state, scn_commit_trans_version))) {
+      trans_id, context_->merge_scn_, read_epoch, state, scn_commit_trans_version))) {
     LOG_WARN("get transaction status failed", K(ret), K(trans_id), K(state));
   } else {
     commit_trans_version = scn_commit_trans_version.get_val_for_tx();
diff --git a/src/storage/compaction/ob_partition_merge_iter.cpp b/src/storage/compaction/ob_partition_merge_iter.cpp
index 816eb8d4c..57772e5b7 100644
--- a/src/storage/compaction/ob_partition_merge_iter.cpp
+++ b/src/storage/compaction/ob_partition_merge_iter.cpp
@@ -140,7 +140,7 @@ int ObPartitionMergeIter::init_query_base_params(const ObMergeParameter &merge_p
         LOG_WARN("Failed to init table access context", K(ret), K(query_flag));
       } else {
         // always use end_scn for safety
-        access_context_.merge_log_ts_ = merge_param.scn_range_.end_scn_.get_val_for_inner_table_field();
+        access_context_.merge_scn_ = merge_param.scn_range_.end_scn_;
       }
     }
   }
diff --git a/src/storage/compaction/ob_tablet_merge_ctx.cpp b/src/storage/compaction/ob_tablet_merge_ctx.cpp
index 327b0e641..4a2cf486a 100644
--- a/src/storage/compaction/ob_tablet_merge_ctx.cpp
+++ b/src/storage/compaction/ob_tablet_merge_ctx.cpp
@@ -193,14 +193,7 @@ int ObTabletMergeInfo::build_create_sstable_param(const ObTabletMergeCtx &ctx,
       table_key.scn_range_ = ctx.scn_range_;
     }
     param.table_key_ = table_key;
-    // TODO(scn):
-    if (INT64_MAX == ctx.merge_scn_) {
-      param.filled_tx_scn_.set_max();
-    } else {
-      if (OB_FAIL(param.filled_tx_scn_.convert_for_lsn_allocator(ctx.merge_scn_))) {
-        LOG_WARN("failed to convert for gts", K(ret), K(ctx));
-      }
-    }
+    param.filled_tx_scn_ = ctx.merge_scn_;
 
     param.table_mode_ = ctx.schema_ctx_.merge_schema_->get_table_mode_struct();
     param.index_type_ = ctx.schema_ctx_.merge_schema_->get_index_type();
@@ -489,7 +482,7 @@ ObTabletMergeCtx::ObTabletMergeCtx(
     allocator_(allocator),
     sstable_version_range_(),
     scn_range_(),
-    merge_scn_(INT64_MAX),
+    merge_scn_(),
     create_snapshot_version_(0),
     tables_handle_(),
     merged_table_handle_(),
@@ -511,6 +504,7 @@ ObTabletMergeCtx::ObTabletMergeCtx(
     time_guard_(),
     rebuild_seq_(-1)
 {
+  merge_scn_.set_max();
 }
 
 ObTabletMergeCtx::~ObTabletMergeCtx()
diff --git a/src/storage/compaction/ob_tablet_merge_ctx.h b/src/storage/compaction/ob_tablet_merge_ctx.h
index 12d0fdf1a..a6bec8857 100644
--- a/src/storage/compaction/ob_tablet_merge_ctx.h
+++ b/src/storage/compaction/ob_tablet_merge_ctx.h
@@ -21,6 +21,7 @@
 #include "storage/compaction/ob_tablet_merge_task.h"
 #include "storage/tx_storage/ob_ls_map.h"
 #include "storage/tx_storage/ob_ls_handle.h"
+#include "logservice/palf/scn.h"
 
 namespace oceanbase
 {
@@ -204,7 +205,7 @@ struct ObTabletMergeCtx
   // 2. filled in ObPartitionStore::get_merge_tables
   ObVersionRange sstable_version_range_;// version range for new sstable
   share::ObScnRange scn_range_;
-  int64_t merge_scn_; // TODO(scn), TODO(danling): change type from int64_t to palf::SCN
+  palf::SCN merge_scn_;
   int64_t create_snapshot_version_;
 
   storage::ObTablesHandleArray tables_handle_;
diff --git a/src/storage/compaction/ob_tablet_merge_task.cpp b/src/storage/compaction/ob_tablet_merge_task.cpp
index 1d82343e6..ec78f6702 100644
--- a/src/storage/compaction/ob_tablet_merge_task.cpp
+++ b/src/storage/compaction/ob_tablet_merge_task.cpp
@@ -617,7 +617,7 @@ int ObTabletMergePrepareTask::process()
       ret = OB_ERR_UNEXPECTED;
       LOG_ERROR("Unexcepted empty log ts range in minor merge", K(ret), K(ctx->scn_range_));
     } else {
-      ctx->merge_scn_ = ctx->scn_range_.end_scn_.get_val_for_inner_table_field();
+      ctx->merge_scn_ = ctx->scn_range_.end_scn_;
     }
   }
 
diff --git a/src/storage/compaction/ob_tx_table_merge_task.cpp b/src/storage/compaction/ob_tx_table_merge_task.cpp
index b84fe8ee8..673232b59 100644
--- a/src/storage/compaction/ob_tx_table_merge_task.cpp
+++ b/src/storage/compaction/ob_tx_table_merge_task.cpp
@@ -145,7 +145,7 @@ int ObTxTableMergePrepareTask::process()
     ret = OB_ERR_UNEXPECTED;
     LOG_ERROR("Unexcepted empty log ts range in minor merge", K(ret), K(ctx->scn_range_));
   } else {
-    ctx->merge_scn_ = ctx->scn_range_.end_scn_.get_val_for_inner_table_field();
+    ctx->merge_scn_ = ctx->scn_range_.end_scn_;
   }
 
   if (OB_FAIL(ret)) {
diff --git a/src/storage/high_availability/ob_storage_ha_tablet_builder.cpp b/src/storage/high_availability/ob_storage_ha_tablet_builder.cpp
index 92da09a8e..6da60e1b6 100644
--- a/src/storage/high_availability/ob_storage_ha_tablet_builder.cpp
+++ b/src/storage/high_availability/ob_storage_ha_tablet_builder.cpp
@@ -632,8 +632,8 @@ int ObStorageHATabletsBuilder::get_remote_logical_minor_scn_range_(
   int ret = OB_SUCCESS;
   scn_range.reset();
   ObArray<ObITable *> sstables;
-  scn_range.start_scn_.convert_for_gts(ObTabletMeta::INIT_CLOG_CHECKPOINT_TS);
-  scn_range.end_scn_.convert_for_gts(ObTabletMeta::INIT_CLOG_CHECKPOINT_TS);
+  scn_range.start_scn_ = ObTabletMeta::INIT_CLOG_CHECKPOINT_SCN;
+  scn_range.end_scn_ = ObTabletMeta::INIT_CLOG_CHECKPOINT_SCN;
 
   if (!is_inited_) {
     ret = OB_NOT_INIT;
diff --git a/src/storage/high_availability/ob_tablet_backfill_tx.cpp b/src/storage/high_availability/ob_tablet_backfill_tx.cpp
index daffd5b8f..b1e199215 100644
--- a/src/storage/high_availability/ob_tablet_backfill_tx.cpp
+++ b/src/storage/high_availability/ob_tablet_backfill_tx.cpp
@@ -656,7 +656,7 @@ int ObTabletTableBackfillTXTask::prepare_merge_ctx_()
     tablet_merge_ctx_.sstable_version_range_.multi_version_start_ = tablet_handle_.get_obj()->get_multi_version_start();
     tablet_merge_ctx_.sstable_version_range_.snapshot_version_ = tablet_handle_.get_obj()->get_snapshot_version();
     tablet_merge_ctx_.scn_range_ = table_handle_.get_table()->get_key().scn_range_;
-    tablet_merge_ctx_.merge_scn_ = backfill_tx_ctx_->log_sync_scn_.get_val_for_lsn_allocator();
+    tablet_merge_ctx_.merge_scn_ = backfill_tx_ctx_->log_sync_scn_;
     tablet_merge_ctx_.create_snapshot_version_ = 0;
 
     if (OB_FAIL(tablet_merge_ctx_.tables_handle_.add_table(table_handle_))) {
diff --git a/src/storage/memtable/ob_memtable_iterator.cpp b/src/storage/memtable/ob_memtable_iterator.cpp
index b19d7ffd2..6bf9b076d 100644
--- a/src/storage/memtable/ob_memtable_iterator.cpp
+++ b/src/storage/memtable/ob_memtable_iterator.cpp
@@ -910,11 +910,7 @@ int ObMemtableMultiVersionScanIterator::init_next_value_iter()
     ret = (OB_SUCCESS == ret) ? OB_ERR_UNEXPECTED : ret;
   } else {
     key_first_row_ = true;
-    // TODO(handora.qc): fix it
-    palf::SCN merge_scn;
-    merge_scn.convert_for_lsn_allocator(context_->merge_log_ts_);
-
-    value_iter_->set_merge_scn(merge_scn);
+    value_iter_->set_merge_scn(context_->merge_scn_);
     row_checker_.reset();
   }
   return ret;
diff --git a/src/storage/ob_partition_range_spliter.cpp b/src/storage/ob_partition_range_spliter.cpp
index 79ba67f54..cc6d41529 100644
--- a/src/storage/ob_partition_range_spliter.cpp
+++ b/src/storage/ob_partition_range_spliter.cpp
@@ -1632,7 +1632,7 @@ int ObPartitionIncrementalRangeSpliter::ObIncrementalIterator::prepare_table_acc
   if (OB_FAIL(tbl_xs_ctx_.init(query_flag, store_ctx_, allocator_, allocator_, scan_version_range))) {
     STORAGE_LOG(WARN, "Failed to init table access context", KR(ret));
   } else {
-    tbl_xs_ctx_.merge_log_ts_ = merge_ctx_.merge_scn_;
+    tbl_xs_ctx_.merge_scn_ = merge_ctx_.merge_scn_;
   }
   return ret;
 }
diff --git a/src/storage/ob_storage_schema_recorder.cpp b/src/storage/ob_storage_schema_recorder.cpp
index a32d28864..275db4955 100644
--- a/src/storage/ob_storage_schema_recorder.cpp
+++ b/src/storage/ob_storage_schema_recorder.cpp
@@ -92,7 +92,7 @@ ObStorageSchemaRecorder::ObStorageSchemaRecorder()
     max_saved_table_version_(OB_INVALID_VERSION),
     clog_buf_(nullptr),
     clog_len_(0),
-    clog_ts_(-1),
+    clog_scn_(),
     schema_guard_(nullptr),
     storage_schema_(nullptr),
     allocator_(nullptr),
@@ -120,7 +120,7 @@ void ObStorageSchemaRecorder::reset()
   ls_id_.reset();
   tablet_id_.reset();
   tablet_handle_.reset();
-  clog_ts_ = -1;
+  clog_scn_.reset();
   clog_len_ = 0;
 }
 
@@ -283,7 +283,7 @@ int ObStorageSchemaRecorder::try_update_storage_schema(
         }
       } else { // sync schema clog success
         FLOG_INFO("finish save table schema", K_(ls_id), K_(tablet_id), K(sync_table_version),
-            "schema_version", storage_schema_->get_schema_version(), K_(clog_ts), K(timeout));
+            "schema_version", storage_schema_->get_schema_version(), K_(clog_scn), K(timeout));
       }
     }
 
@@ -342,9 +342,9 @@ void ObStorageSchemaRecorder::update_table_schema_succ(
     ret = OB_INVALID_ARGUMENT;
     LOG_ERROR("schema log with smaller table version", K(ret), K_(tablet_id),
         K(table_version), K(max_saved_table_version_));
-  } else if (OB_UNLIKELY(clog_ts_ <= 0 || nullptr == storage_schema_)) {
+  } else if (OB_UNLIKELY(!clog_scn_.is_valid() || clog_scn_.is_min() || nullptr == storage_schema_)) {
     ret = OB_ERR_UNEXPECTED;
-    LOG_WARN("clog ts or storage schema is invalid", K(ret), K_(clog_ts), KP_(storage_schema));
+    LOG_WARN("clog ts or storage schema is invalid", K(ret), K_(clog_scn), KP_(storage_schema));
   } else if (storage_schema_->get_schema_version() != table_version) {
     LOG_ERROR("schema version not match", K(storage_schema_), K(table_version));
   }
@@ -369,7 +369,7 @@ int ObStorageSchemaRecorder::dec_ref_on_memtable(const bool sync_finish)
         KP_(storage_schema), K_(tablet_handle));
   } else {
     storage_schema_->set_sync_finish(sync_finish);
-    if (OB_FAIL(tablet_handle_.get_obj()->save_multi_source_data_unit(storage_schema_, clog_ts_,
+    if (OB_FAIL(tablet_handle_.get_obj()->save_multi_source_data_unit(storage_schema_, clog_scn_.get_val_for_tx(),
         false/*for_replay*/, memtable::MemtableRefOp::DEC_REF, true/*is_callback*/))) {
       LOG_WARN("failed to save storage schema", K(ret), K_(tablet_id), K(storage_schema_));
     }
@@ -471,9 +471,8 @@ int ObStorageSchemaRecorder::submit_schema_log(const int64_t table_id)
 {
   int ret = OB_SUCCESS;
   const bool need_nonblock = false;
-  const int64_t ref_ts_ns = 0;
   palf::LSN lsn;
-  clog_ts_ = -1;
+  clog_scn_.reset();
 
   if (OB_UNLIKELY(nullptr == log_handler_ || nullptr == storage_schema_
       || !tablet_handle_.is_valid()
@@ -501,7 +500,7 @@ int ObStorageSchemaRecorder::submit_schema_log(const int64_t table_id)
     if (OB_BLOCK_FROZEN != ret) {
       LOG_WARN("failed to inc ref for storage schema", K(ret), K_(tablet_id), K(storage_schema_));
     }
-  } else if (OB_FAIL(log_handler_->append(clog_buf_, clog_len_, ref_ts_ns, need_nonblock, logcb_ptr_, lsn, clog_ts_))) {
+  } else if (OB_FAIL(log_handler_->append(clog_buf_, clog_len_, palf::SCN::min_scn(), need_nonblock, logcb_ptr_, lsn, clog_scn_))) {
     LOG_WARN("fail to submit log", K(ret), K_(tablet_id));
     int tmp_ret = OB_SUCCESS;
     if (OB_TMP_FAIL(dec_ref_on_memtable(false))) {
diff --git a/src/storage/ob_storage_schema_recorder.h b/src/storage/ob_storage_schema_recorder.h
index 6a3853780..33916ab25 100644
--- a/src/storage/ob_storage_schema_recorder.h
+++ b/src/storage/ob_storage_schema_recorder.h
@@ -21,6 +21,7 @@
 #include "storage/ob_storage_schema.h"
 #include "storage/meta_mem/ob_tablet_handle.h"
 #include "share/schema/ob_multi_version_schema_service.h"
+#include "logservice/palf/scn.h"
 
 namespace oceanbase
 {
@@ -127,7 +128,7 @@ private:
   int64_t max_saved_table_version_;
   char *clog_buf_;
   int64_t clog_len_;
-  int64_t clog_ts_;
+  palf::SCN clog_scn_;
 
   share::schema::ObSchemaGetterGuard *schema_guard_;
   ObStorageSchema *storage_schema_;
diff --git a/src/storage/tablet/ob_tablet_meta.cpp b/src/storage/tablet/ob_tablet_meta.cpp
index 09eb49509..e8ba9cc23 100644
--- a/src/storage/tablet/ob_tablet_meta.cpp
+++ b/src/storage/tablet/ob_tablet_meta.cpp
@@ -26,7 +26,7 @@ using namespace blocksstable;
 using namespace palf;
 namespace storage
 {
-const int64_t ObTabletMeta::INIT_CLOG_CHECKPOINT_TS = 1;
+const palf::SCN ObTabletMeta::INIT_CLOG_CHECKPOINT_SCN = palf::SCN::base_scn();
 
 ObTabletMeta::ObTabletMeta()
   : version_(TABLET_META_VERSION),
diff --git a/src/storage/tablet/ob_tablet_meta.h b/src/storage/tablet/ob_tablet_meta.h
index 6841b410c..6075aaa5f 100644
--- a/src/storage/tablet/ob_tablet_meta.h
+++ b/src/storage/tablet/ob_tablet_meta.h
@@ -43,7 +43,7 @@ struct ObMigrationTabletParam;
 class ObTabletMeta final
 {
 public:
-  static const int64_t INIT_CLOG_CHECKPOINT_TS;
+  static const palf::SCN INIT_CLOG_CHECKPOINT_SCN;
 
 public:
   ObTabletMeta();
diff --git a/src/storage/tablet/ob_tablet_table_store.cpp b/src/storage/tablet/ob_tablet_table_store.cpp
index a4f20aab5..890f383f1 100644
--- a/src/storage/tablet/ob_tablet_table_store.cpp
+++ b/src/storage/tablet/ob_tablet_table_store.cpp
@@ -1394,13 +1394,9 @@ int ObTabletTableStore::combin_ha_minor_sstables_(
     common::ObIArray<ObITable *> &new_minor_sstables)
 {
   int ret = OB_SUCCESS;
-  //TODO(SCN) TabletMeta::INIT_CLOG_CHECKPOINT_TS should be SCN
-  palf::SCN logical_start_scn;
-  logical_start_scn.convert_for_lsn_allocator(ObTabletMeta::INIT_CLOG_CHECKPOINT_TS);
-  palf::SCN logical_end_scn;
-  logical_end_scn.convert_for_lsn_allocator(ObTabletMeta::INIT_CLOG_CHECKPOINT_TS);
-  palf::SCN max_copy_end_scn;
-  max_copy_end_scn.convert_for_lsn_allocator(ObTabletMeta::INIT_CLOG_CHECKPOINT_TS);
+  palf::SCN logical_start_scn = ObTabletMeta::INIT_CLOG_CHECKPOINT_SCN;
+  palf::SCN logical_end_scn = ObTabletMeta::INIT_CLOG_CHECKPOINT_SCN;
+  palf::SCN max_copy_end_scn = ObTabletMeta::INIT_CLOG_CHECKPOINT_SCN;
   int64_t old_store_minor_tables_index = 0;
 
   //get remote logical minor sstable log ts
@@ -1441,7 +1437,7 @@ int ObTabletTableStore::combin_ha_minor_sstables_(
         }
       }
 
-      if (OB_SUCC(ret) && !found && ObTabletMeta::INIT_CLOG_CHECKPOINT_TS != logical_end_scn.get_val_for_inner_table_field()) {
+      if (OB_SUCC(ret) && !found && ObTabletMeta::INIT_CLOG_CHECKPOINT_SCN != logical_end_scn) {
         ret = OB_ERR_UNEXPECTED;
         LOG_WARN("can not find table continue with old table store", K(ret),
             K(old_store_minor_sstables), K(logical_start_scn), K(logical_end_scn), K(need_add_minor_sstables));