diff --git a/src/tsdb/src/tsdbMemTable.c b/src/tsdb/src/tsdbMemTable.c
index 401ab1ed246fcf38e2bb8d6c96d2e327e06a04f2..1cd212b216d73c9824323c2c7e0e62a8188bd548 100644
--- a/src/tsdb/src/tsdbMemTable.c
+++ b/src/tsdb/src/tsdbMemTable.c
@@ -32,8 +32,8 @@ static void        tsdbEndCommit(STsdbRepo *pRepo);
 static int         tsdbHasDataToCommit(SCommitIter *iters, int nIters, TSKEY minKey, TSKEY maxKey);
 static int  tsdbCommitToFile(STsdbRepo *pRepo, int fid, SCommitIter *iters, SRWHelper *pHelper, SDataCols *pDataCols);
 static void tsdbGetFidKeyRange(int daysPerFile, int8_t precision, int fileId, TSKEY *minKey, TSKEY *maxKey);
-static SCommitIter *tsdbCreateTableIters(STsdbRepo *pRepo);
-static void         tsdbDestroyTableIters(SCommitIter *iters, int maxTables);
+static SCommitIter *tsdbCreateCommitIters(STsdbRepo *pRepo);
+static void         tsdbDestroyCommitIters(SCommitIter *iters, int maxTables);
 
 // ---------------- INTERNAL FUNCTIONS ----------------
 int tsdbInsertRowToMem(STsdbRepo *pRepo, SDataRow row, STable *pTable) {
@@ -430,7 +430,7 @@ static void *tsdbCommitData(void *arg) {
 
   // Create the iterator to read from cache
   if (pMem->numOfRows > 0) {
-    iters = tsdbCreateTableIters(pRepo);
+    iters = tsdbCreateCommitIters(pRepo);
     if (iters == NULL) {
       tsdbError("vgId:%d failed to create commit iterator since %s", REPO_ID(pRepo), tstrerror(terrno));
       goto _exit;
@@ -470,7 +470,7 @@ static void *tsdbCommitData(void *arg) {
 
 _exit:
   tdFreeDataCols(pDataCols);
-  tsdbDestroyTableIters(iters, pCfg->maxTables);
+  tsdbDestroyCommitIters(iters, pCfg->maxTables);
   tsdbDestroyHelper(&whelper);
   tsdbEndCommit(pRepo);
   tsdbInfo("vgId:%d commit over", pRepo->config.tsdbId);
@@ -636,7 +636,7 @@ _err:
   return -1;
 }
 
-static SCommitIter *tsdbCreateTableIters(STsdbRepo *pRepo) {
+static SCommitIter *tsdbCreateCommitIters(STsdbRepo *pRepo) {
   STsdbCfg * pCfg = &(pRepo->config);
   SMemTable *pMem = pRepo->imem;
   STsdbMeta *pMeta = pRepo->tsdbMeta;
@@ -666,21 +666,18 @@ static SCommitIter *tsdbCreateTableIters(STsdbRepo *pRepo) {
         goto _err;
       }
 
-      if (!tSkipListIterNext(iters[i].pIter)) {
-        terrno = TSDB_CODE_TDB_NO_TABLE_DATA_IN_MEM;
-        goto _err;
-      }
+      tSkipListIterNext(iters[i].pIter);
     }
   }
 
   return iters;
 
 _err:
-  tsdbDestroyTableIters(iters, pCfg->maxTables);
+  tsdbDestroyCommitIters(iters, pCfg->maxTables);
   return NULL;
 }
 
-static void tsdbDestroyTableIters(SCommitIter *iters, int maxTables) {
+static void tsdbDestroyCommitIters(SCommitIter *iters, int maxTables) {
   if (iters == NULL) return;
 
   for (int i = 1; i < maxTables; i++) {
diff --git a/src/tsdb/src/tsdbRWHelper.c b/src/tsdb/src/tsdbRWHelper.c
index 000302af57c73d8071734478d23e5cda6f845d7f..4edb29e712afa28e346a51334040f0d08b8bfee0 100644
--- a/src/tsdb/src/tsdbRWHelper.c
+++ b/src/tsdb/src/tsdbRWHelper.c
@@ -230,8 +230,12 @@ void tsdbSetHelperTable(SRWHelper *pHelper, STable *pTable, STsdbRepo *pRepo) {
   tdInitDataCols(pHelper->pDataCols[1], pSchema);
 
   SCompIdx *pIdx = pHelper->pCompIdx + pTable->tableId.tid;
-  if (pIdx->offset > 0 && pIdx->hasLast) {
-    pHelper->hasOldLastBlock = true;
+  if (pIdx->offset > 0) {
+    if (pIdx->uid != TABLE_UID(pTable)) {
+      memset((void *)pIdx, 0, sizeof(SCompIdx));
+    } else {
+      if (pIdx->hasLast) pHelper->hasOldLastBlock = true;
+    }
   }
 
   helperSetState(pHelper, TSDB_HELPER_TABLE_SET);
@@ -244,11 +248,11 @@ int tsdbCommitTableData(SRWHelper *pHelper, SCommitIter *pCommitIter, SDataCols
   SCompIdx * pIdx = &(pHelper->pCompIdx[TABLE_TID(pCommitIter->pTable)]);
   int        blkIdx = 0;
 
-  ASSERT(TABLE_TID(pCommitIter->pTable) == pHelper->tableInfo.tid);
-  if (TABLE_UID(pCommitIter->pTable) != pIdx->uid) memset((void *)pIdx, 0, sizeof(*pIdx));
+  ASSERT(pIdx->offset == 0 || pIdx->uid == TABLE_UID(pCommitIter->pTable));
   if (tsdbLoadCompInfo(pHelper, NULL) < 0) return -1;
 
   while (true) {
+    ASSERT(blkIdx <= pIdx->numOfBlocks);
     TSKEY keyFirst = tsdbNextIterKey(pCommitIter->pIter);
     if (keyFirst < 0 || keyFirst > maxKey) break;  // iter over
 
@@ -268,28 +272,42 @@ int tsdbMoveLastBlockIfNeccessary(SRWHelper *pHelper) {
 
   ASSERT(helperType(pHelper) == TSDB_WRITE_HELPER);
   SCompIdx * pIdx = pHelper->pCompIdx + pHelper->tableInfo.tid;
-  SCompBlock compBlock;
-  if ((pHelper->files.nLastF.fd > 0) && (pHelper->hasOldLastBlock)) {
+  SCompBlock compBlock = {0};
+  if (TSDB_NLAST_FILE_OPENED(pHelper) && (pHelper->hasOldLastBlock)) {
     if (tsdbLoadCompInfo(pHelper, NULL) < 0) return -1;
 
-    SCompBlock *pCompBlock = pHelper->pCompInfo->blocks + pIdx->numOfBlocks - 1;
+    SCompBlock *pCompBlock = blockAtIdx(pHelper, pIdx->numOfBlocks - 1);
     ASSERT(pCompBlock->last);
 
     if (pCompBlock->numOfSubBlocks > 1) {
-      if (tsdbLoadBlockData(pHelper, blockAtIdx(pHelper, pIdx->numOfBlocks - 1), NULL) < 0) return -1;
-      ASSERT(pHelper->pDataCols[0]->numOfRows > 0 && pHelper->pDataCols[0]->numOfRows < pCfg->minRowsPerFileBlock);
+      if (tsdbLoadBlockData(pHelper, pCompBlock, NULL) < 0) return -1;
+      ASSERT(pHelper->pDataCols[0]->numOfRows == pCompBlock->numOfRows &&
+             pHelper->pDataCols[0]->numOfRows < pCfg->minRowsPerFileBlock);
       if (tsdbWriteBlockToFile(pHelper, &(pHelper->files.nLastF), pHelper->pDataCols[0], &compBlock, true, true) < 0)
         return -1;
 
       if (tsdbUpdateSuperBlock(pHelper, &compBlock, pIdx->numOfBlocks - 1) < 0) return -1;
-
     } else {
-      if (lseek(pHelper->files.lastF.fd, pCompBlock->offset, SEEK_SET) < 0) return -1;
+      if (lseek(pHelper->files.lastF.fd, pCompBlock->offset, SEEK_SET) < 0) {
+        tsdbError("vgId:%d failed to lseek file %s since %s", REPO_ID(pHelper->pRepo), pHelper->files.lastF.fname,
+                  strerror(errno));
+        terrno = TAOS_SYSTEM_ERROR(errno);
+        return -1;
+      }
       pCompBlock->offset = lseek(pHelper->files.nLastF.fd, 0, SEEK_END);
-      if (pCompBlock->offset < 0) return -1;
+      if (pCompBlock->offset < 0) {
+        tsdbError("vgId:%d failed to lseek file %s since %s", REPO_ID(pHelper->pRepo), pHelper->files.nLastF.fname,
+                  strerror(errno));
+        terrno = TAOS_SYSTEM_ERROR(errno);
+        return -1;
+      }
 
-      if (tsendfile(pHelper->files.nLastF.fd, pHelper->files.lastF.fd, NULL, pCompBlock->len) < pCompBlock->len)
+      if (tsendfile(pHelper->files.nLastF.fd, pHelper->files.lastF.fd, NULL, pCompBlock->len) < pCompBlock->len) {
+        tsdbError("vgId:%d failed to sendfile from file %s to file %s since %s", REPO_ID(pHelper->pRepo),
+                  pHelper->files.lastF.fname, pHelper->files.nLastF.fname, strerror(errno));
+        terrno = TAOS_SYSTEM_ERROR(errno);
         return -1;
+      }
     }
 
     pHelper->hasOldLastBlock = false;
@@ -354,7 +372,12 @@ int tsdbWriteCompIdx(SRWHelper *pHelper) {
 
   ASSERT(helperType(pHelper) == TSDB_WRITE_HELPER);
   off_t offset = lseek(pHelper->files.nHeadF.fd, 0, SEEK_END);
-  if (offset < 0) return -1;
+  if (offset < 0) {
+    tsdbError("vgId:%d failed to lseek file %s to end since %s", REPO_ID(pHelper->pRepo), pHelper->files.nHeadF.fname,
+              strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
+  }
 
   SFile *pFile = &(pHelper->files.nHeadF);
   pFile->info.offset = offset;
@@ -366,6 +389,10 @@ int tsdbWriteCompIdx(SRWHelper *pHelper) {
       int drift = POINTER_DISTANCE(buf, pHelper->pBuffer);
       if (tsizeof(pHelper->pBuffer) - drift < 128) {
         pHelper->pBuffer = trealloc(pHelper->pBuffer, tsizeof(pHelper->pBuffer) * 2);
+        if (pHelper->pBuffer == NULL) {
+          terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+          return -1;
+        }
       }
       buf = POINTER_SHIFT(pHelper->pBuffer, drift);
       taosEncodeVariantU32(&buf, i);
@@ -376,7 +403,12 @@ int tsdbWriteCompIdx(SRWHelper *pHelper) {
   int tsize = (char *)buf - (char *)pHelper->pBuffer + sizeof(TSCKSUM);
   taosCalcChecksumAppend(0, (uint8_t *)pHelper->pBuffer, tsize);
 
-  if (twrite(pHelper->files.nHeadF.fd, (void *)pHelper->pBuffer, tsize) < tsize) return -1;
+  if (twrite(pHelper->files.nHeadF.fd, (void *)pHelper->pBuffer, tsize) < tsize) {
+    tsdbError("vgId:%d failed to write %d bytes to file %s since %s", REPO_ID(pHelper->pRepo), tsize,
+              pHelper->files.nHeadF.fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
+  }
   pFile->info.len = tsize;
   return 0;
 }
@@ -1327,7 +1359,10 @@ static int tsdbProcessAppendCommit(SRWHelper *pHelper, SCommitIter *pCommitIter,
       if (tsdbWriteBlockToProperFile(pHelper, pHelper->pDataCols[0], &compBlock) < 0) return -1;
       if (tsdbUpdateSuperBlock(pHelper, &compBlock, pIdx->numOfBlocks - 1) < 0) return -1;
     }
+
+    if (pHelper->hasOldLastBlock) pHelper->hasOldLastBlock = false;
   } else {
+    ASSERT(!pHelper->hasOldLastBlock);
     tdResetDataCols(pDataCols);
     int rowsRead = tsdbLoadDataFromCache(pTable, pCommitIter->pIter, maxKey, defaultRowsInBlock, pDataCols, NULL, 0);
     ASSERT(rowsRead > 0 && rowsRead == pDataCols->numOfRows);
@@ -1359,7 +1394,7 @@ static int tsdbProcessMergeCommit(SRWHelper *pHelper, SCommitIter *pCommitIter,
   int tblkIdx = TSDB_GET_COMPBLOCK_IDX(pHelper, pCompBlock);
 
   if (pCompBlock->last) {
-    ASSERT(pCompBlock->numOfRows < pCfg->minRowsPerFileBlock);
+    ASSERT(pCompBlock->numOfRows < pCfg->minRowsPerFileBlock && tblkIdx == pIdx->numOfBlocks - 1);
     int16_t colId = 0;
     slIter = *(pCommitIter->pIter);
     if (tsdbLoadBlockDataCols(pHelper, pCompBlock, NULL, &colId, 1) < 0) return -1;
@@ -1378,36 +1413,41 @@ static int tsdbProcessMergeCommit(SRWHelper *pHelper, SCommitIter *pCommitIter,
                                              pDataCols0->cols[0].pData, pDataCols0->numOfRows);
         ASSERT(rowsRead == rows2 && rowsRead == pDataCols->numOfRows);
         if (tsdbWriteBlockToFile(pHelper, &(pHelper->files.lastF), pDataCols, &compBlock, true, false) < 0) return -1;
-        if (tsdbAddSubBlock(pHelper, &compBlock, pIdx->numOfBlocks - 1, rowsRead) < 0) return -1;
+        if (tsdbAddSubBlock(pHelper, &compBlock, tblkIdx, rowsRead) < 0) return -1;
         tblkIdx++;
       } else {
         if (tsdbLoadBlockData(pHelper, pCompBlock, NULL) < 0) return -1;
         int round = 0;
         int dIter = 0;
         while (true) {
+          tdResetDataCols(pDataCols);
           int rowsRead =
               tsdbLoadAndMergeFromCache(pDataCols0, &dIter, pCommitIter, pDataCols, maxKey, defaultRowsInBlock);
           if (rowsRead == 0) break;
 
           if (tsdbWriteBlockToProperFile(pHelper, pDataCols, &compBlock) < 0) return -1;
           if (round == 0) {
-            if (tsdbUpdateSuperBlock(pHelper, &compBlock, pIdx->numOfBlocks - 1) < 0) return -1;
+            if (tsdbUpdateSuperBlock(pHelper, &compBlock, tblkIdx) < 0) return -1;
           } else {
-            if (tsdbInsertSuperBlock(pHelper, &compBlock, pIdx->numOfBlocks) < 0) return -1;
+            if (tsdbInsertSuperBlock(pHelper, &compBlock, tblkIdx) < 0) return -1;
           }
 
           tblkIdx++;
           round++;
         }
       }
+      if (pHelper->hasOldLastBlock) pHelper->hasOldLastBlock = false;
     }
   } else {
     TSKEY keyLimit = (tblkIdx == pIdx->numOfBlocks - 1) ? maxKey : (pCompBlock[1].keyFirst - 1);
-    if (keyFirst < pCompBlock->keyFirst) {
+    TSKEY blkKeyFirst = pCompBlock->keyFirst;
+    TSKEY blkKeyLast = pCompBlock->keyLast;
+
+    if (keyFirst < blkKeyFirst) {
       while (true) {
         tdResetDataCols(pDataCols);
         int rowsRead =
-            tsdbLoadDataFromCache(pTable, pCommitIter->pIter, keyLimit, defaultRowsInBlock, pDataCols, NULL, 0);
+            tsdbLoadDataFromCache(pTable, pCommitIter->pIter, blkKeyFirst - 1, defaultRowsInBlock, pDataCols, NULL, 0);
         if (rowsRead == 0) break;
 
         ASSERT(rowsRead == pDataCols->numOfRows);
@@ -1416,14 +1456,14 @@ static int tsdbProcessMergeCommit(SRWHelper *pHelper, SCommitIter *pCommitIter,
         tblkIdx++;
       }
     } else {
-      ASSERT(keyFirst <= pCompBlock->keyLast);
+      ASSERT(keyFirst <= blkKeyLast);
       int16_t colId = 0;
       if (tsdbLoadBlockDataCols(pHelper, pCompBlock, NULL, &colId, 1) < 0) return -1;
-      ASSERT(pHelper->pDataCols[0]->numOfRows == pCompBlock->numOfRows);
+      ASSERT(pDataCols0->numOfRows == pCompBlock->numOfRows);
 
       slIter = *(pCommitIter->pIter);
       int rows1 = (pCfg->maxRowsPerFileBlock - pCompBlock->numOfRows);
-      int rows2 = tsdbLoadDataFromCache(pTable, &slIter, pCompBlock->keyLast, INT_MAX, NULL, pDataCols0->cols[0].pData,
+      int rows2 = tsdbLoadDataFromCache(pTable, &slIter, blkKeyLast, INT_MAX, NULL, pDataCols0->cols[0].pData,
                                         pDataCols0->numOfRows);
 
       if (rows2 == 0) {  // all filtered out