diff --git a/src/vnode/tsdb/src/tsdbRWHelper.c b/src/vnode/tsdb/src/tsdbRWHelper.c
index 2e01d9efeccf5d3affd344685a70c4c6b03436fd..d543b1283149a77a516179e4ec0254d1a0999d9c 100644
--- a/src/vnode/tsdb/src/tsdbRWHelper.c
+++ b/src/vnode/tsdb/src/tsdbRWHelper.c
@@ -188,18 +188,17 @@ int tsdbWriteDataBlock(SRWHelper *pHelper, SDataCols *pDataCols) {
   TSKEY      keyFirst = dataColsKeyFirst(pDataCols);
 
   ASSERT(helperHasState(pHelper, TSDB_HELPER_IDX_LOAD));
-  SCompIdx  curIdx = pHelper->compIdx; // old table SCompIdx for sendfile usage
-  SCompIdx *pIdx = pHelper->pCompIdx + pHelper->tableInfo.tid; // for change purpose
+  // SCompIdx  curIdx = pHelper->compIdx;                          // old table SCompIdx for sendfile usage
+  SCompIdx *pIdx = pHelper->pCompIdx + pHelper->tableInfo.tid;  // for change purpose
 
   // Load the SCompInfo part if neccessary
   ASSERT(helperHasState(pHelper, TSDB_HELPER_TABLE_SET));
   if ((!helperHasState(pHelper, TSDB_HELPER_INFO_LOAD)) &&
-      ((pIdx->offset > 0) && (pIdx->hasLast || dataColsKeyFirst(pDataCols) <= pIdx->maxKey)) &&
-      (tsdbLoadCompInfo(pHelper, NULL) < 0))
-    goto _err;
+      ((pIdx->offset > 0) && (pIdx->hasLast || keyFirst <= pIdx->maxKey))) {
+    if (tsdbLoadCompInfo(pHelper, NULL) < 0) goto _err;
+  }
 
-  if (!pIdx->hasLast && keyFirst > pIdx->maxKey) {
-    // Just need to append as a super block
+  if (pIdx->offset == 0 || (!pIdx->hasLast && keyFirst > pIdx->maxKey)) {  // Just append as a super block
     rowsToWrite = pDataCols->numOfPoints;
     SFile *pWFile = NULL;
     bool   isLast = false;
@@ -218,39 +217,48 @@ int tsdbWriteDataBlock(SRWHelper *pHelper, SDataCols *pDataCols) {
 
     pIdx->hasLast = compBlock.last;
     pIdx->numOfSuperBlocks++;
-    pIdx->maxKey = dataColsKeyLast(pDataCols);
-    // pIdx->len = ??????
-  } else { // (pIdx->hasLast) OR (keyFirst <= pIdx->maxKey)
-    if (keyFirst > pIdx->maxKey) {
-      int blkIdx = pIdx->numOfSuperBlocks - 1;
-      ASSERT(pIdx->hasLast && pHelper->pCompInfo->blocks[blkIdx].last);
-
-      // Need to merge with the last block
-      if (tsdbMergeDataWithBlock(pHelper, blkIdx, pDataCols) < 0) goto _err;
-    } else {
-      // Find the first block greater or equal to the block
-      SCompBlock *pCompBlock = taosbsearch((void *)(&keyFirst), (void *)(pHelper->pCompInfo->blocks),
-                                           pIdx->numOfSuperBlocks, sizeof(SCompBlock), compareKeyBlock, TD_GE);
-      if (pCompBlock == NULL) {
-        if (tsdbMergeDataWithBlock(pHelper, pIdx->numOfSuperBlocks-1, pDataCols) < 0) goto _err;
-      } else {
-        if (compareKeyBlock((void *)(&keyFirst), (void *)pCompBlock) == 0) {
-          SCompBlock *pNextBlock = NULL;
-          TSKEY keyLimit = (pNextBlock == NULL) ? INT_MAX : (pNextBlock->keyFirst - 1);
-          rowsToWrite =
-              MIN(nRowsLEThan(pDataCols, keyLimit), pHelper->config.maxRowsPerFileBlock - pCompBlock->numOfPoints);
-          
-          if (tsdbMergeDataWithBlock(pHelper, pCompBlock-pHelper->pCompInfo->blocks, pDataCols) < 0) goto _err;
+    pIdx->maxKey = compBlock.keyLast;
+    ASSERT(compBlock.keyLast == dataColsKeyLast(pDataCols));
+    pIdx->len += sizeof(SCompBlock);
+  } else {  // (Has old data) AND ((has last block) OR (key overlap)), need to merge the block
+    SCompBlock *pCompBlock = taosbsearch((void *)(&keyFirst), (void *)(pHelper->pCompInfo->blocks),
+                                         pIdx->numOfSuperBlocks, sizeof(SCompBlock), compareKeyBlock, TD_GE);
+
+    int blkIdx = (pCompBlock == NULL) ? (pIdx->numOfSuperBlocks - 1) : (pCompBlock - pHelper->pCompInfo->blocks);
+
+    if (pCompBlock == NULL) {  // No key overlap, must has last block, just merge with the last block
+      ASSERT(pIdx->hasLast && pHelper->pCompInfo->blocks[pIdx->numOfSuperBlocks - 1].last);
+      rowsToWrite = tsdbMergeDataWithBlock(pHelper, blkIdx, pDataCols);
+      if (rowsToWrite < 0) goto _err;
+    } else {  // Has key overlap
+
+      if (compareKeyBlock((void *)(&keyFirst), (void *)pCompBlock) == 0) { // Key overlap with the block
+        // TSKEY keyLimit =
+        //     (blkIdx == pIdx->numOfSuperBlocks - 1) ? INT_MAX : (pHelper->pCompInfo->blocks[blkIdx + 1].keyFirst - 1);
+
+        rowsToWrite = tsdbMergeDataWithBlock(pHelper, blkIdx, pDataCols);
+        if (rowsToWrite < 0) goto _err;
+
+        ASSERT(rowsToWrite == MIN(rows1, rows2));
+      } else { // Either merge with the previous block or save as a super block in the middle
+        SCompBlock *prevBlock = (blkIdx == 0) ? NULL : (pCompBlock - 1);
+
+        int rows1 = nRowsLEThan(pDataCols, pCompBlock->keyFirst); // rows write as a super block in the middle
+        int rows2 = (prevBlock) ? (pHelper->config.maxRowsPerFileBlock - prevBlock->numOfPoints)
+                                : rows1;  // rows can merge with the previous block
+        if (rows1 >= rows2) {
+          rowsToWrite = tsdbWriteBlockToFile(pHelper, &(pHelper->files.dataF), pDataCols, rows1, &compBlock, false, true);
+          if (rowsToWrite < 0) goto _err;
+
+          ASSERT(rowsToWrite == rows1);
+
+          // Add the super block to it
+          pIdx->len += sizeof(SCompBlock);
+          pIdx->numOfSuperBlocks++;
         } else {
-          // There options: 1. merge with previous block
-          //                2. commit as one block
-          //                3. merge with current block
-          int nRows1 = INT_MAX;
-          int nRows2 = nRowsLEThan(pDataCols, pCompBlock->keyFirst);
-          int nRows3 = MIN(nRowsLEThan(pDataCols, (pCompBlock + 1)->keyFirst), (pHelper->config.maxRowsPerFileBlock - pCompBlock->numOfPoints));
-
-          // TODO: find the block with max rows can merge
-          if (tsdbMergeDataWithBlock(pHelper, pCompBlock, pDataCols) < 0) goto _err;
+          rowsToWrite = tsdbMergeDataWithBlock(pHelper, blkIdx-1, pDataCols);
+          if (rowsToWrite < 0) goto _err;
+          ASSERT(rowsToWrite == rows2);
         }
       }
     }
@@ -258,7 +266,7 @@ int tsdbWriteDataBlock(SRWHelper *pHelper, SDataCols *pDataCols) {
 
   return rowsToWrite;
 
-  _err:
+_err:
   return -1;
 }
 
@@ -309,7 +317,7 @@ int tsdbLoadCompInfo(SRWHelper *pHelper, void *target) {
     if (lseek(fd, curCompIdx.offset, SEEK_SET) < 0) return -1;
 
     adjustMem(pHelper->pCompInfo, pHelper->compInfoSize, curCompIdx.len);
-    if (tread(fd, (void *)(pHelper->pCompInfo), pHelper) < 0) return -1;
+    if (tread(fd, (void *)(pHelper->pCompInfo), pHelper->compIdx.len) < pHelper->compIdx.len) return -1;
     // TODO: check the checksum
 
     helperSetState(pHelper, TSDB_HELPER_INFO_LOAD);
@@ -521,8 +529,14 @@ static int compareKeyBlock(const void *arg1, const void *arg2) {
   return 0;
 }
 
+static FORCE_INLINE int compKeyFunc(const void *arg1, const void *arg2) {
+  return ((*(TSKEY *)arg1) - (*(TSKEY *)arg2));
+}
+
 static int nRowsLEThan(SDataCols *pDataCols, int maxKey) {
-  return 0;
+  void *ptr = taosbsearch((void *)&maxKey, pDataCols->cols[0].pData, pDataCols->numOfPoints, sizeof(TSKEY), compKeyFunc, TD_LE);
+  if (ptr == NULL) return 0;
+  return ((TSKEY *)ptr - (TSKEY *)(pDataCols->cols[0].pData)) + 1;
 }
 
 static int tsdbMergeDataWithBlock(SRWHelper *pHelper, int blkIdx, SDataCols *pDataCols) {