diff --git a/source/dnode/vnode/src/tsdb/dev/inc/tsdbIter.h b/source/dnode/vnode/src/tsdb/dev/inc/tsdbIter.h
index ed46bfe8841af1347d8b84edf660cb88d0781787..41f0c76adee8490a200591f4d1962854c5d92aa6 100644
--- a/source/dnode/vnode/src/tsdb/dev/inc/tsdbIter.h
+++ b/source/dnode/vnode/src/tsdb/dev/inc/tsdbIter.h
@@ -55,12 +55,13 @@ int32_t tsdbIterClose(STsdbIter **iter);
 int32_t tsdbIterNext(STsdbIter *iter);
 
 // SIterMerger ===============
-int32_t      tsdbIterMergerOpen(const TTsdbIterArray *iterArray, SIterMerger **merger, bool isTomb);
-int32_t      tsdbIterMergerClose(SIterMerger **merger);
-int32_t      tsdbIterMergerNext(SIterMerger *merger);
-SRowInfo    *tsdbIterMergerGet(SIterMerger *merger);
+int32_t tsdbIterMergerOpen(const TTsdbIterArray *iterArray, SIterMerger **merger, bool isTomb);
+int32_t tsdbIterMergerClose(SIterMerger **merger);
+int32_t tsdbIterMergerNext(SIterMerger *merger);
+int32_t tsdbIterMergerSkipTableData(SIterMerger *merger, const TABLEID *tbid);
+
+SRowInfo    *tsdbIterMergerGetData(SIterMerger *merger);
 STombRecord *tsdbIterMergerGetTombRecord(SIterMerger *merger);
-int32_t      tsdbIterMergerSkipTableData(SIterMerger *merger, const TABLEID *tbid);
 
 #ifdef __cplusplus
 }
diff --git a/source/dnode/vnode/src/tsdb/dev/tsdbCommit.c b/source/dnode/vnode/src/tsdb/dev/tsdbCommit.c
index 6a43f13d0127f43a440b3645d896ab7ff615e744..9c7d05138e0cec1868a16a23cc1e02b88272863a 100644
--- a/source/dnode/vnode/src/tsdb/dev/tsdbCommit.c
+++ b/source/dnode/vnode/src/tsdb/dev/tsdbCommit.c
@@ -178,7 +178,7 @@ static int32_t tsdbCommitTSData(SCommitter2 *committer) {
   TSDB_CHECK_CODE(code, lino, _exit);
 
   // loop iter
-  while ((row = tsdbIterMergerGet(committer->iterMerger)) != NULL) {
+  while ((row = tsdbIterMergerGetData(committer->iterMerger)) != NULL) {
     if (row->uid != committer->ctx->tbid->uid) {
       committer->ctx->tbid->suid = row->suid;
       committer->ctx->tbid->uid = row->uid;
diff --git a/source/dnode/vnode/src/tsdb/dev/tsdbIter.c b/source/dnode/vnode/src/tsdb/dev/tsdbIter.c
index f0078f93f05b420b43dfd1c64b06a317dab9bd77..6b614d7e84013bac5264878ba29391f14b7d6e12 100644
--- a/source/dnode/vnode/src/tsdb/dev/tsdbIter.c
+++ b/source/dnode/vnode/src/tsdb/dev/tsdbIter.c
@@ -544,6 +544,7 @@ static int32_t tsdbTombIterCmprFn(const SRBTreeNode *n1, const SRBTreeNode *n2)
 
 // SIterMerger ================
 struct SIterMerger {
+  bool       isTomb;
   STsdbIter *iter;
   SRBTree    iterTree[1];
 };
@@ -553,8 +554,11 @@ int32_t tsdbIterMergerOpen(const TTsdbIterArray *iterArray, SIterMerger **merger
   SRBTreeNode *node;
 
   merger[0] = taosMemoryCalloc(1, sizeof(*merger[0]));
-  if (!merger[0]) return TSDB_CODE_OUT_OF_MEMORY;
+  if (merger[0] == NULL) {
+    return TSDB_CODE_OUT_OF_MEMORY;
+  }
 
+  merger[0]->isTomb = isTomb;
   if (isTomb) {
     tRBTreeCreate(merger[0]->iterTree, tsdbTombIterCmprFn);
   } else {
@@ -599,15 +603,22 @@ int32_t tsdbIterMergerNext(SIterMerger *merger) {
     }
   }
 
-  if (!merger->iter && (node = tRBTreeDropMin(merger->iterTree))) {
+  if (merger->iter == NULL && (node = tRBTreeDropMin(merger->iterTree))) {
     merger->iter = TCONTAINER_OF(node, STsdbIter, node);
   }
 
   return 0;
 }
 
-SRowInfo    *tsdbIterMergerGet(SIterMerger *merger) { return merger->iter ? merger->iter->row : NULL; }
-STombRecord *tsdbIterMergerGetTombRecord(SIterMerger *merger) { return merger->iter ? merger->iter->record : NULL; }
+SRowInfo *tsdbIterMergerGetData(SIterMerger *merger) {
+  ASSERT(!merger->isTomb);
+  return merger->iter ? merger->iter->row : NULL;
+}
+
+STombRecord *tsdbIterMergerGetTombRecord(SIterMerger *merger) {
+  ASSERT(merger->isTomb);
+  return merger->iter ? merger->iter->record : NULL;
+}
 
 int32_t tsdbIterMergerSkipTableData(SIterMerger *merger, const TABLEID *tbid) {
   int32_t      code;
diff --git a/source/dnode/vnode/src/tsdb/dev/tsdbMerge.c b/source/dnode/vnode/src/tsdb/dev/tsdbMerge.c
index 3f45301efe3d3b257670b1bc507d1f903f9699e9..eb4fb18ddd82fb92b042ad4ae5097aff49ed949d 100644
--- a/source/dnode/vnode/src/tsdb/dev/tsdbMerge.c
+++ b/source/dnode/vnode/src/tsdb/dev/tsdbMerge.c
@@ -199,7 +199,7 @@ static int32_t tsdbMergeToDataLevel(SMerger *merger) {
   int32_t lino = 0;
 
   // data
-  for (SRowInfo *row; (row = tsdbIterMergerGet(merger->dataIterMerger)) != NULL;) {
+  for (SRowInfo *row; (row = tsdbIterMergerGetData(merger->dataIterMerger)) != NULL;) {
     if (row->uid != merger->ctx->tbid->uid) {
       code = tsdbMergeToDataTableEnd(merger);
       TSDB_CHECK_CODE(code, lino, _exit);
@@ -273,7 +273,7 @@ static int32_t tsdbMergeToUpperLevel(SMerger *merger) {
 
   // data
   SRowInfo *row;
-  while ((row = tsdbIterMergerGet(merger->dataIterMerger))) {
+  while ((row = tsdbIterMergerGetData(merger->dataIterMerger))) {
     code = tsdbSttFileWriteRow(merger->sttWriter, row);
     TSDB_CHECK_CODE(code, lino, _exit);