diff --git a/source/dnode/vnode/src/inc/tsdb.h b/source/dnode/vnode/src/inc/tsdb.h
index d9288753f312f5d303ad68a29371241683dda6a2..f97de5eecf411b9b75d3a8b1cddeb281d1cbfdcc 100644
--- a/source/dnode/vnode/src/inc/tsdb.h
+++ b/source/dnode/vnode/src/inc/tsdb.h
@@ -64,6 +64,7 @@ typedef struct SDelFWriter    SDelFWriter;
 typedef struct SDelFReader    SDelFReader;
 typedef struct SRowIter       SRowIter;
 typedef struct STsdbFS        STsdbFS;
+typedef struct SRowMerger     SRowMerger;
 
 #define TSDB_MAX_SUBBLOCKS 8
 
@@ -86,6 +87,11 @@ int32_t tGetTSDBRow(uint8_t *p, TSDBROW *pRow);
 // SRowIter
 void     tRowIterInit(SRowIter *pIter, TSDBROW *pRow, STSchema *pTSchema);
 SColVal *tRowIterNext(SRowIter *pIter);
+// SRowMerger
+int32_t tRowMergerInit(SRowMerger *pMerger, TSDBROW *pRow, STSchema *pTSchema);
+void    tRowMergerClear(SRowMerger *pMerger);
+int32_t tRowMerge(SRowMerger *pMerger, TSDBROW *pRow);
+int32_t tRowMergerGetRow(SRowMerger *pMerger, STSRow **ppRow);
 // TABLEID
 int32_t tTABLEIDCmprFn(const void *p1, const void *p2);
 // TSDBKEY
@@ -429,6 +435,7 @@ struct SDelIdx {
 };
 
 struct SDelFile {
+  int64_t commitID;
   TSKEY   minKey;
   TSKEY   maxKey;
   int64_t minVersion;
@@ -462,25 +469,21 @@ struct SHeadFile {
   int64_t commitID;
   int64_t size;
   int64_t offset;
-  int32_t nRef;
 };
 
 struct SDataFile {
   int64_t commitID;
   int64_t size;
-  int32_t nRef;
 };
 
 struct SLastFile {
   int64_t commitID;
   int64_t size;
-  int32_t nRef;
 };
 
 struct SSmaFile {
   int64_t commitID;
   int64_t size;
-  int32_t nRef;
 };
 
 struct SDFileSet {
@@ -490,7 +493,10 @@ struct SDFileSet {
   SDataFile *pDataFile;
   SLastFile *pLastFile;
   SSmaFile  *pSmaFile;
-  int32_t    nRef;
+  // SHeadFile headFile;
+  // SDataFile dataFile;
+  // SLastFile lastFile;
+  // SSmaFile  smaFile;
 };
 
 struct SRowIter {
@@ -499,6 +505,11 @@ struct SRowIter {
   SColVal   colVal;
   int32_t   i;
 };
+struct SRowMerger {
+  STSchema *pTSchema;
+  int64_t   version;
+  SArray   *pArray;  // SArray<SColVal>
+};
 
 #ifdef __cplusplus
 }
diff --git a/source/dnode/vnode/src/tsdb/tsdbCommit.c b/source/dnode/vnode/src/tsdb/tsdbCommit.c
index 7814d5905b4014723b8623c36eaa373740e8ac70..445a4c5ae924bb2010f849c8dd0360f5d34a3ac9 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCommit.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCommit.c
@@ -896,7 +896,7 @@ static int32_t tsdbCommitData(SCommitter *pCommitter) {
 
   // start ====================
   code = tsdbCommitDataStart(pCommitter);
-  if (code) return code;
+  if (code) goto _err;
 
   // impl ====================
   pCommitter->nextKey = pMemTable->minKey;
diff --git a/source/dnode/vnode/src/tsdb/tsdbUtil.c b/source/dnode/vnode/src/tsdb/tsdbUtil.c
index acff2dfa5433ec4dede7f41ccc74dc305807712f..a9c91119ae6e68b27c777685c56d4beb27ef223e 100644
--- a/source/dnode/vnode/src/tsdb/tsdbUtil.c
+++ b/source/dnode/vnode/src/tsdb/tsdbUtil.c
@@ -586,6 +586,83 @@ SColVal *tRowIterNext(SRowIter *pIter) {
   return NULL;
 }
 
+// SRowMerger ======================================================
+int32_t tRowMergerInit(SRowMerger *pMerger, TSDBROW *pRow, STSchema *pTSchema) {
+  int32_t   code = 0;
+  TSDBKEY   key = tsdbRowKey(pRow);
+  SColVal  *pColVal = &(SColVal){0};
+  STColumn *pTColumn;
+
+  pMerger->pTSchema = pTSchema;
+  pMerger->version = key.version;
+
+  pMerger->pArray = taosArrayInit(pTSchema->numOfCols, sizeof(SColVal));
+  if (pMerger->pArray == NULL) {
+    code = TSDB_CODE_OUT_OF_MEMORY;
+    goto _exit;
+  }
+
+  // ts
+  pTColumn = &pTSchema->columns[0];
+
+  ASSERT(pTColumn->type == TSDB_DATA_TYPE_TIMESTAMP);
+
+  *pColVal = COL_VAL_VALUE(pTColumn->colId, pTColumn->type, (SValue){.ts = key.ts});
+  if (taosArrayPush(pMerger->pArray, pColVal) == NULL) {
+    code = TSDB_CODE_OUT_OF_MEMORY;
+    goto _exit;
+  }
+
+  // other
+  for (int16_t iCol = 1; iCol < pTSchema->numOfCols; iCol++) {
+    tsdbRowGetColVal(pRow, pTSchema, iCol, pColVal);
+    if (taosArrayPush(pMerger->pArray, pColVal) == NULL) {
+      code = TSDB_CODE_OUT_OF_MEMORY;
+      goto _exit;
+    }
+  }
+
+_exit:
+  return code;
+}
+
+void tRowMergerClear(SRowMerger *pMerger) { taosArrayDestroy(pMerger->pArray); }
+
+int32_t tRowMerge(SRowMerger *pMerger, TSDBROW *pRow) {
+  int32_t  code = 0;
+  TSDBKEY  key = tsdbRowKey(pRow);
+  SColVal *pColVal = &(SColVal){0};
+
+  ASSERT(((SColVal *)pMerger->pArray->pData)->value.ts == key.ts);
+
+  for (int32_t iCol = 1; iCol < pMerger->pTSchema->numOfCols; iCol++) {
+    tsdbRowGetColVal(pRow, pMerger->pTSchema, iCol, pColVal);
+    if (pColVal->isNone) continue;
+
+    // SColVal *tColVal = (SColVal *)taosArrayGet(pMerger->pArray, iCol);
+
+    if (key.version > pMerger->version) {
+      // forward merge (todo)
+    } else if (key.version < pMerger->version) {
+      // backward merge (todo)
+    } else {
+      ASSERT(0);
+    }
+  }
+
+  pMerger->version = key.version;
+
+_exit:
+  return code;
+}
+
+int32_t tRowMergerGetRow(SRowMerger *pMerger, STSRow **ppRow) {
+  int32_t code = 0;
+  // TODO
+  ASSERT(0);
+  return code;
+}
+
 // delete skyline ======================================================
 static int32_t tsdbMergeSkyline(SArray *aSkyline1, SArray *aSkyline2, SArray *aSkyline) {
   int32_t  code = 0;