diff --git a/src/tsdb/src/tsdbMain.c b/src/tsdb/src/tsdbMain.c
index c09d5fffba9de0d9e37bded5734ce8da3bd96442..e6d7b2e875021f9494c6e9fd8a29f280f2bddf30 100644
--- a/src/tsdb/src/tsdbMain.c
+++ b/src/tsdb/src/tsdbMain.c
@@ -557,6 +557,7 @@ static STsdbRepo *tsdbNewRepo(STsdbCfg *pCfg, STsdbAppH *pAppH) {
   pRepo->state = TSDB_STATE_OK;
   pRepo->code = TSDB_CODE_SUCCESS;
   pRepo->compactState = 0;
+  pRepo->truncateState = 0;
   pRepo->config = *pCfg;
   if (pAppH) {
     pRepo->appH = *pAppH;
diff --git a/src/tsdb/src/tsdbReadImpl.c b/src/tsdb/src/tsdbReadImpl.c
index 4976e8b8fb8213b6a9cdedbf380d812e117f1fc8..98fac3df7717157676b5c9ebd309c9413bfc8914 100644
--- a/src/tsdb/src/tsdbReadImpl.c
+++ b/src/tsdb/src/tsdbReadImpl.c
@@ -682,7 +682,6 @@ static int tsdbLoadBlockDataImpl(SReadH *pReadh, SBlock *pBlock, SDataCols *pDat
     uint32_t toffset = TSDB_KEY_COL_OFFSET;
     int32_t  tlen = pBlock->keyLen;
 
-
     if (dcol != 0) {
       tsdbGetSBlockCol(pBlock, &pBlockCol, pBlockData->cols, ccol);
       tcolId = pBlockCol->colId;
diff --git a/src/tsdb/src/tsdbTruncate.c b/src/tsdb/src/tsdbTruncate.c
index da0e8fb6026312fcf8cb0e952f42505d56e5c464..63402f162c066aa122f3bc3b9811e2f6281ca522 100644
--- a/src/tsdb/src/tsdbTruncate.c
+++ b/src/tsdb/src/tsdbTruncate.c
@@ -24,7 +24,7 @@ typedef struct {
 typedef struct {
   SRtn       rtn;
   SFSIter    fsIter;
-  SArray *   tbArray;  // STableTruncateH, table array to cache table obj and block indexes
+  SArray *   tblArray;  // STableTruncateH, table array to cache table obj and block indexes
   SReadH     readh;
   SDFileSet  wSet;
   SArray *   aBlkIdx;
@@ -51,8 +51,8 @@ static int  tsdbTruncateTSData(STsdbRepo *pRepo, void *param);
 static int  tsdbTruncateFSet(STruncateH *pTruncateH, SDFileSet *pSet);
 static int  tsdbInitTruncateH(STruncateH *pTruncateH, STsdbRepo *pRepo);
 static void tsdbDestroyTruncateH(STruncateH *pTruncateH);
-static int  tsdbInitCompTbArray(STruncateH *pTruncateH);
-static void tsdbDestroyCompTbArray(STruncateH *pTruncateH);
+static int  tsdbInitTruncateTblArray(STruncateH *pTruncateH);
+static void tsdbDestroyTruncateTblArray(STruncateH *pTruncateH);
 static int  tsdbCacheFSetIndex(STruncateH *pTruncateH);
 static int  tsdbTruncateCache(STsdbRepo *pRepo, void *param);
 static int  tsdbTruncateFSetInit(STruncateH *pTruncateH, SDFileSet *pSet);
@@ -250,6 +250,7 @@ static int tsdbTruncateFSet(STruncateH *pTruncateH, SDFileSet *pSet) {
 
   tsdbInitDFileSet(TSDB_TRUNCATE_WSET(pTruncateH), did, REPO_ID(pRepo), TSDB_FSET_FID(pSet),
                    FS_TXN_VERSION(REPO_FS(pRepo)), TSDB_LATEST_FSET_VER);
+
   if (tsdbCreateDFileSet(TSDB_TRUNCATE_WSET(pTruncateH), true) < 0) {
     tsdbError("vgId:%d failed to truncate FSET %d since %s", REPO_ID(pRepo), pSet->fid, tstrerror(terrno));
     tsdbTruncateFSetEnd(pTruncateH);
@@ -285,7 +286,7 @@ static int tsdbInitTruncateH(STruncateH *pTruncateH, STsdbRepo *pRepo) {
     return -1;
   }
 
-  if (tsdbInitCompTbArray(pTruncateH) < 0) {
+  if (tsdbInitTruncateTblArray(pTruncateH) < 0) {
     tsdbDestroyTruncateH(pTruncateH);
     return -1;
   }
@@ -318,33 +319,33 @@ static void tsdbDestroyTruncateH(STruncateH *pTruncateH) {
   pTruncateH->pDataCols = tdFreeDataCols(pTruncateH->pDataCols);
   pTruncateH->aSupBlk = taosArrayDestroy(pTruncateH->aSupBlk);
   pTruncateH->aBlkIdx = taosArrayDestroy(pTruncateH->aBlkIdx);
-  tsdbDestroyCompTbArray(pTruncateH);
+  tsdbDestroyTruncateTblArray(pTruncateH);
   tsdbDestroyReadH(&(pTruncateH->readh));
   tsdbCloseDFileSet(TSDB_TRUNCATE_WSET(pTruncateH));
 }
 
-static int tsdbInitCompTbArray(STruncateH *pTruncateH) {  // Init pComp->tbArray
+static int tsdbInitTruncateTblArray(STruncateH *pTruncateH) {
   STsdbRepo *pRepo = TSDB_TRUNCATE_REPO(pTruncateH);
   STsdbMeta *pMeta = pRepo->tsdbMeta;
 
   if (tsdbRLockRepoMeta(pRepo) < 0) return -1;
 
-  pTruncateH->tbArray = taosArrayInit(pMeta->maxTables, sizeof(STableTruncateH));
-  if (pTruncateH->tbArray == NULL) {
+  pTruncateH->tblArray = taosArrayInit(pMeta->maxTables, sizeof(STableTruncateH));
+  if (pTruncateH->tblArray == NULL) {
     terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
     tsdbUnlockRepoMeta(pRepo);
     return -1;
   }
 
   // Note here must start from 0
-  for (int i = 0; i < pMeta->maxTables; i++) {
+  for (int i = 0; i < pMeta->maxTables; ++i) {
     STableTruncateH ch = {0};
     if (pMeta->tables[i] != NULL) {
       tsdbRefTable(pMeta->tables[i]);
       ch.pTable = pMeta->tables[i];
     }
 
-    if (taosArrayPush(pTruncateH->tbArray, &ch) == NULL) {
+    if (taosArrayPush(pTruncateH->tblArray, &ch) == NULL) {
       terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
       tsdbUnlockRepoMeta(pRepo);
       return -1;
@@ -355,22 +356,21 @@ static int tsdbInitCompTbArray(STruncateH *pTruncateH) {  // Init pComp->tbArray
   return 0;
 }
 
-static void tsdbDestroyCompTbArray(STruncateH *pTruncateH) {
-  STableTruncateH *pTh;
+static void tsdbDestroyTruncateTblArray(STruncateH *pTruncateH) {
+  STableTruncateH *pTblHandle = NULL;
 
-  if (pTruncateH->tbArray == NULL) return;
+  if (pTruncateH->tblArray == NULL) return;
 
-  for (size_t i = 0; i < taosArrayGetSize(pTruncateH->tbArray); i++) {
-    pTh = (STableTruncateH *)taosArrayGet(pTruncateH->tbArray, i);
-    if (pTh->pTable) {
-      tsdbUnRefTable(pTh->pTable);
+  for (size_t i = 0; i < taosArrayGetSize(pTruncateH->tblArray); ++i) {
+    pTblHandle = (STableTruncateH *)taosArrayGet(pTruncateH->tblArray, i);
+    if (pTblHandle->pTable) {
+      tsdbUnRefTable(pTblHandle->pTable);
     }
 
-    // pTh->pInfo = taosTZfree(pTh->pInfo);
-    tfree(pTh->pInfo);
+    tfree(pTblHandle->pInfo);
   }
 
-  pTruncateH->tbArray = taosArrayDestroy(pTruncateH->tbArray);
+  pTruncateH->tblArray = taosArrayDestroy(pTruncateH->tblArray);
 }
 
 static int tsdbCacheFSetIndex(STruncateH *pTruncateH) {
@@ -380,21 +380,22 @@ static int tsdbCacheFSetIndex(STruncateH *pTruncateH) {
     return -1;
   }
 
-  for (int tid = 1; tid < taosArrayGetSize(pTruncateH->tbArray); tid++) {
-    STableTruncateH *pTh = (STableTruncateH *)taosArrayGet(pTruncateH->tbArray, tid);
-    pTh->pBlkIdx = NULL;
+  size_t tblArraySize = taosArrayGetSize(pTruncateH->tblArray);
+  for (size_t tid = 1; tid < tblArraySize; ++tid) {
+    STableTruncateH *pTblHandle = (STableTruncateH *)taosArrayGet(pTruncateH->tblArray, tid);
+    pTblHandle->pBlkIdx = NULL;
 
-    if (pTh->pTable == NULL) continue;
-    if (tsdbSetReadTable(pReadH, pTh->pTable) < 0) {
+    if (pTblHandle->pTable == NULL) continue;
+    if (tsdbSetReadTable(pReadH, pTblHandle->pTable) < 0) {
       return -1;
     }
 
     if (pReadH->pBlkIdx == NULL) continue;
-    pTh->bIndex = *(pReadH->pBlkIdx);
-    pTh->pBlkIdx = &(pTh->bIndex);
+    pTblHandle->bIndex = *(pReadH->pBlkIdx);
+    pTblHandle->pBlkIdx = &(pTblHandle->bIndex);
 
     uint32_t originLen = 0;
-    if (tsdbLoadBlockInfo(pReadH, (void **)(&(pTh->pInfo)), &originLen) < 0) {
+    if (tsdbLoadBlockInfo(pReadH, (void **)(&(pTblHandle->pInfo)), &originLen) < 0) {
       return -1;
     }
   }
@@ -424,7 +425,7 @@ static int tsdbTruncateFSetImpl(STruncateH *pTruncateH) {
   STsdbRepo *pRepo = TSDB_TRUNCATE_REPO(pTruncateH);
   STsdbCfg * pCfg = REPO_CFG(pRepo);
   SReadH *   pReadh = &(pTruncateH->readh);
-  SBlockIdx  blkIdx;
+  SBlockIdx  blkIdx = {0};
   void **    ppBuf = &(TSDB_TRUNCATE_BUF(pTruncateH));
   void **    ppCBuf = &(TSDB_TRUNCATE_COMP_BUF(pTruncateH));
   void **    ppExBuf = &(TSDB_TRUNCATE_EXBUF(pTruncateH));
@@ -432,51 +433,60 @@ static int tsdbTruncateFSetImpl(STruncateH *pTruncateH) {
 
   taosArrayClear(pTruncateH->aBlkIdx);
 
-  for (int tid = 1; tid < taosArrayGetSize(pTruncateH->tbArray); tid++) {
-    STableTruncateH *pTh = (STableTruncateH *)taosArrayGet(pTruncateH->tbArray, tid);
-    STSchema *       pSchema;
+  for (size_t tid = 1; tid < taosArrayGetSize(pTruncateH->tblArray); ++tid) {
+    STableTruncateH *pTblHandle = (STableTruncateH *)taosArrayGet(pTruncateH->tblArray, tid);
+    STSchema *       pSchema = NULL;
+
+    if (pTblHandle->pTable == NULL || pTblHandle->pBlkIdx == NULL) continue;
 
-    if (pTh->pTable == NULL || pTh->pBlkIdx == NULL) continue;
+    if ((pSchema = tsdbGetTableSchemaImpl(pTblHandle->pTable, true, true, -1, -1)) == NULL) {
+      return -1;
+    }
 
-    pSchema = tsdbGetTableSchemaImpl(pTh->pTable, true, true, -1, -1);
     taosArrayClear(pTruncateH->aSupBlk);
+
     if ((tdInitDataCols(pTruncateH->pDataCols, pSchema) < 0) || (tdInitDataCols(pReadh->pDCols[0], pSchema) < 0) ||
         (tdInitDataCols(pReadh->pDCols[1], pSchema) < 0)) {
       terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
       tdFreeSchema(pSchema);
       return -1;
     }
+
     tdFreeSchema(pSchema);
 
     // Loop to truncate each block data
-    for (int i = 0; i < pTh->pBlkIdx->numOfBlocks; i++) {
-      SBlock *pBlock = pTh->pInfo->blocks + i;
+    for (int i = 0; i < pTblHandle->pBlkIdx->numOfBlocks; ++i) {
+      SBlock *pBlock = pTblHandle->pInfo->blocks + i;
 
       // Load the block data
-      if (tsdbLoadBlockData(pReadh, pBlock, pTh->pInfo) < 0) {
+      if (tsdbLoadBlockData(pReadh, pBlock, pTblHandle->pInfo) < 0) {
         return -1;
       }
 
       // Merge pTruncateH->pDataCols and pReadh->pDCols[0] and write data to file
-      if (pTruncateH->pDataCols->numOfRows == 0 && pBlock->numOfRows >= defaultRows) {
-        if (tsdbWriteBlockToRightFile(pTruncateH, pTh->pTable, pReadh->pDCols[0], ppBuf, ppCBuf, ppExBuf) < 0) {
+      if ((pTruncateH->pDataCols->numOfRows == 0) && (pBlock->numOfRows >= defaultRows)) {
+        // if pTruncateH->pDataCols has no data and pBlock->numOfRows >= defaultRows, write data directly
+        if (tsdbWriteBlockToRightFile(pTruncateH, pTblHandle->pTable, pReadh->pDCols[0], ppBuf, ppCBuf, ppExBuf) < 0) {
           return -1;
         }
       } else {
         int ridx = 0;
-
         while (true) {
-          if (pReadh->pDCols[0]->numOfRows - ridx == 0) break;
+          // no data left to merge anymore
+          if ((pReadh->pDCols[0]->numOfRows - ridx) == 0) break;
+
+          // min(data left, target space left)
           int rowsToMerge = MIN(pReadh->pDCols[0]->numOfRows - ridx, defaultRows - pTruncateH->pDataCols->numOfRows);
 
           tdMergeDataCols(pTruncateH->pDataCols, pReadh->pDCols[0], rowsToMerge, &ridx,
                           pCfg->update != TD_ROW_PARTIAL_UPDATE);
 
           if (pTruncateH->pDataCols->numOfRows < defaultRows) {
+            // continue to read more blocks
             break;
           }
 
-          if (tsdbWriteBlockToRightFile(pTruncateH, pTh->pTable, pTruncateH->pDataCols, ppBuf, ppCBuf, ppExBuf) < 0) {
+          if (tsdbWriteBlockToRightFile(pTruncateH, pTblHandle->pTable, pTruncateH->pDataCols, ppBuf, ppCBuf, ppExBuf) < 0) {
             return -1;
           }
           tdResetDataCols(pTruncateH->pDataCols);
@@ -485,16 +495,16 @@ static int tsdbTruncateFSetImpl(STruncateH *pTruncateH) {
     }
 
     if (pTruncateH->pDataCols->numOfRows > 0 &&
-        tsdbWriteBlockToRightFile(pTruncateH, pTh->pTable, pTruncateH->pDataCols, ppBuf, ppCBuf, ppExBuf) < 0) {
+        tsdbWriteBlockToRightFile(pTruncateH, pTblHandle->pTable, pTruncateH->pDataCols, ppBuf, ppCBuf, ppExBuf) < 0) {
       return -1;
     }
 
-    if (tsdbWriteBlockInfoImpl(TSDB_TRUNCATE_HEAD_FILE(pTruncateH), pTh->pTable, pTruncateH->aSupBlk, NULL, ppBuf,
+    if (tsdbWriteBlockInfoImpl(TSDB_TRUNCATE_HEAD_FILE(pTruncateH), pTblHandle->pTable, pTruncateH->aSupBlk, NULL, ppBuf,
                                &blkIdx) < 0) {
       return -1;
     }
 
-    if ((blkIdx.numOfBlocks > 0) && (taosArrayPush(pTruncateH->aBlkIdx, (void *)(&blkIdx)) == NULL)) {
+    if ((blkIdx.numOfBlocks > 0) && (taosArrayPush(pTruncateH->aBlkIdx, (const void *)(&blkIdx)) == NULL)) {
       terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
       return -1;
     }
@@ -511,9 +521,9 @@ static int tsdbWriteBlockToRightFile(STruncateH *pTruncateH, STable *pTable, SDa
                                      void **ppCBuf, void **ppExBuf) {
   STsdbRepo *pRepo = TSDB_TRUNCATE_REPO(pTruncateH);
   STsdbCfg * pCfg = REPO_CFG(pRepo);
-  SDFile *   pDFile;
-  bool       isLast;
-  SBlock     block;
+  SDFile *   pDFile = NULL;
+  bool       isLast = false;
+  SBlock     block = {0};
 
   ASSERT(pDataCols->numOfRows > 0);