diff --git a/source/dnode/vnode/src/tsdb/tsdbSnapshot.c b/source/dnode/vnode/src/tsdb/tsdbSnapshot.c
index 29a64cf0b5..dbf710bb20 100644
--- a/source/dnode/vnode/src/tsdb/tsdbSnapshot.c
+++ b/source/dnode/vnode/src/tsdb/tsdbSnapshot.c
@@ -28,13 +28,15 @@ struct STsdbSnapReader {
   SDataFReader* pDataFReader;
   SArray*       aBlockIdx;  // SArray<SBlockIdx>
   SArray*       aBlockL;    // SArray<SBlockL>
-  int32_t       iBlockIdx;
   SBlockIdx*    pBlockIdx;
-  int32_t       iBlockL;
-  SMapData      mBlock;  // SMapData<SBlock>
-  int32_t       iBlock;
-  SBlockData    oBlockData;
-  SBlockData    nBlockData;
+  SBlockL*      pBlockL;
+
+  int32_t    iBlockIdx;
+  int32_t    iBlockL;
+  SMapData   mBlock;  // SMapData<SBlock>
+  int32_t    iBlock;
+  SBlockData oBlockData;
+  SBlockData nBlockData;
   // for del file
   int8_t       delDone;
   SDelFReader* pDelFReader;
@@ -75,96 +77,42 @@ static int32_t tsdbSnapReadData(STsdbSnapReader* pReader, uint8_t** ppData) {
     }
 
     while (true) {
-#if 0
-      if (pReader->pBlockIdx == NULL) {
-        if (pReader->iBlockIdx >= taosArrayGetSize(pReader->aBlockIdx)) {
-          tsdbDataFReaderClose(&pReader->pDataFReader);
-          break;
+      if (pReader->pBlockIdx && pReader->pBlockL) {
+      } else if (pReader->pBlockIdx) {
+        // may have problem (todo)
+        while (pReader->iBlock < pReader->mBlock.nItem) {
+          SBlock block;
+          tMapDataGetItemByIdx(&pReader->mBlock, pReader->iBlock, &block, tGetBlock);
+
+          if (block.minVer <= pReader->ever && block.maxVer >= pReader->sver) {
+            // load data (todo)
+          }
+
+          // next
+          pReader->iBlock++;
+
+          if (*ppData) goto _exit;
         }
+      } else if (pReader->pBlockL) {
+        while (pReader->pBlockL) {
+          if (pReader->pBlockL->minVer <= pReader->ever && pReader->pBlockL->maxVer >= pReader->sver) {
+            // load data (todo)
+          }
 
-        pReader->pBlockIdx = (SBlockIdx*)taosArrayGet(pReader->aBlockIdx, pReader->iBlockIdx);
-        pReader->iBlockIdx++;
+          // next
+          pReader->iBlockL++;
+          if (pReader->iBlockL < taosArrayGetSize(pReader->aBlockL)) {
+            pReader->pBlockL = (SBlockL*)taosArrayGetSize(pReader->aBlockL);
+          } else {
+            pReader->pBlockL = NULL;
+          }
 
-        code = tsdbReadBlock(pReader->pDataFReader, pReader->pBlockIdx, &pReader->mBlock);
-        if (code) goto _err;
-
-        pReader->iBlock = 0;
+          if (*ppData) goto _exit;
+        }
+      } else {
+        tsdbDataFReaderClose(&pReader->pDataFReader);
+        break;
       }
-
-      SBlock  block;
-      SBlock* pBlock = &block;
-      while (true) {
-        if (pReader->iBlock >= pReader->mBlock.nItem) {
-          pReader->pBlockIdx = NULL;
-          break;
-        }
-
-        tMapDataGetItemByIdx(&pReader->mBlock, pReader->iBlock, pBlock, tGetBlock);
-        pReader->iBlock++;
-
-        if (pBlock->minVersion > pReader->ever || pBlock->maxVersion < pReader->sver) continue;
-
-        code = tsdbReadBlockData(pReader->pDataFReader, pReader->pBlockIdx, pBlock, &pReader->oBlockData, NULL, NULL);
-        if (code) goto _err;
-
-        // filter
-        tBlockDataReset(&pReader->nBlockData);
-        for (int32_t iColData = 0; iColData < taosArrayGetSize(pReader->oBlockData.aIdx); iColData++) {
-          SColData* pColDataO = tBlockDataGetColDataByIdx(&pReader->oBlockData, iColData);
-          SColData* pColDataN = NULL;
-
-          code = tBlockDataAddColData(&pReader->nBlockData, taosArrayGetSize(pReader->nBlockData.aIdx), &pColDataN);
-          if (code) goto _err;
-
-          tColDataInit(pColDataN, pColDataO->cid, pColDataO->type, pColDataO->smaOn);
-        }
-
-        for (int32_t iRow = 0; iRow < pReader->oBlockData.nRow; iRow++) {
-          TSDBROW row = tsdbRowFromBlockData(&pReader->oBlockData, iRow);
-          int64_t version = TSDBROW_VERSION(&row);
-
-          tsdbTrace("vgId:%d, vnode snapshot tsdb read for %s, %" PRId64 "(%" PRId64 " , %" PRId64 ")",
-                    TD_VID(pReader->pTsdb->pVnode), pReader->pTsdb->path, version, pReader->sver, pReader->ever);
-
-          if (version < pReader->sver || version > pReader->ever) continue;
-
-          code = tBlockDataAppendRow(&pReader->nBlockData, &row, NULL);
-          if (code) goto _err;
-        }
-
-        if (pReader->nBlockData.nRow <= 0) {
-          continue;
-        }
-
-        // org data
-        // compress data (todo)
-        int32_t size = sizeof(TABLEID) + tPutBlockData(NULL, &pReader->nBlockData);
-
-        *ppData = taosMemoryMalloc(sizeof(SSnapDataHdr) + size);
-        if (*ppData == NULL) {
-          code = TSDB_CODE_OUT_OF_MEMORY;
-          goto _err;
-        }
-
-        SSnapDataHdr* pHdr = (SSnapDataHdr*)(*ppData);
-        pHdr->type = pReader->type;
-        pHdr->size = size;
-
-        TABLEID* pId = (TABLEID*)(&pHdr[1]);
-        pId->suid = pReader->pBlockIdx->suid;
-        pId->uid = pReader->pBlockIdx->uid;
-
-        tPutBlockData((uint8_t*)(&pId[1]), &pReader->nBlockData);
-
-        // tsdbInfo("vgId:%d, vnode snapshot read data for %s, fid:%d suid:%" PRId64 " uid:%" PRId64
-        //          " iBlock:%d minVersion:%d maxVersion:%d nRow:%d out of %d size:%d",
-        //          TD_VID(pTsdb->pVnode), pTsdb->path, pReader->fid, pReader->pBlockIdx->suid, pReader->pBlockIdx->uid,
-        //          pReader->iBlock - 1, pBlock->minVersion, pBlock->maxVersion, pReader->nBlockData.nRow, pBlock->nRow,
-        //          size);
-
-        goto _exit;
-      }
-#endif
     }
   }