diff --git a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
index 950c9348af..d660dfa99d 100644
--- a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
+++ b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
@@ -120,6 +120,92 @@ static SBlockData* loadBlockIfMissing(SLDataIter *pIter) {
   return NULL;
 }
 
+// find the earliest block that contains the required records
+static FORCE_INLINE int32_t findEarliestIndex(int32_t index, uint64_t uid, const SSttBlk* pBlockList, int32_t num, int32_t backward) {
+  int32_t i = index;
+  int32_t step = backward? 1:-1;
+  while (i >= 0 && i < num && uid >= pBlockList[i].minUid && uid <= pBlockList[i].maxUid) {
+    i += step;
+  }
+  return i - step;
+}
+
+static int32_t binarySearchForStartBlock(SSttBlk*pBlockList, int32_t num, uint64_t uid, int32_t backward) {
+  int32_t midPos = -1;
+  if (num <= 0) {
+    return -1;
+  }
+
+  int32_t firstPos = 0;
+  int32_t lastPos = num - 1;
+
+  // find the first position which is bigger than the key
+  if ((uid > pBlockList[lastPos].maxUid) || (uid < pBlockList[firstPos].minUid)) {
+    return -1;
+  }
+
+  while (1) {
+    if (uid >= pBlockList[firstPos].minUid && uid <= pBlockList[firstPos].maxUid) {
+      return findEarliestIndex(firstPos, uid, pBlockList, num, backward);
+    }
+
+    if (uid > pBlockList[lastPos].maxUid || uid < pBlockList[firstPos].minUid) {
+      return -1;
+    }
+
+    int32_t numOfRows = lastPos - firstPos + 1;
+    midPos = (numOfRows >> 1u) + firstPos;
+
+    if (uid < pBlockList[midPos].minUid) {
+      lastPos = midPos - 1;
+    } else if (uid > pBlockList[midPos].maxUid) {
+      firstPos = midPos + 1;
+    } else {
+      return findEarliestIndex(midPos, uid, pBlockList, num, backward);
+    }
+  }
+}
+
+static FORCE_INLINE int32_t findEarliestRow(int32_t index, uint64_t uid, const uint64_t* uidList, int32_t num, int32_t backward) {
+  int32_t i = index;
+  int32_t step = backward? 1:-1;
+  while (i >= 0 && i < num && uid == uidList[i]) {
+    i += step;
+  }
+  return i - step;
+}
+
+static int32_t binarySearchForStartRowIndex(uint64_t* uidList, int32_t num, uint64_t uid, int32_t backward) {
+  int32_t firstPos = 0;
+  int32_t lastPos = num - 1;
+
+  // find the first position which is bigger than the key
+  if ((uid > uidList[lastPos]) || (uid < uidList[firstPos])) {
+    return -1;
+  }
+
+  while (1) {
+    if (uid == uidList[firstPos]) {
+      return findEarliestRow(firstPos, uid, uidList, num, backward);
+    }
+
+    if (uid > uidList[lastPos] || uid < uidList[firstPos]) {
+      return -1;
+    }
+
+    int32_t numOfRows = lastPos - firstPos + 1;
+    int32_t midPos = (numOfRows >> 1u) + firstPos;
+
+    if (uid < uidList[midPos]) {
+      lastPos = midPos - 1;
+    } else if (uid > uidList[midPos]) {
+      firstPos = midPos + 1;
+    } else {
+      return findEarliestRow(midPos, uid, uidList, num, backward);
+    }
+  }
+}
+
 int32_t tLDataIterOpen(struct SLDataIter **pIter, SDataFReader *pReader, int32_t iStt, int8_t backward, uint64_t suid,
                        uint64_t uid, STimeWindow *pTimeWindow, SVersionRange *pRange, SSttBlockLoadInfo* pBlockLoadInfo) {
   int32_t code = 0;
@@ -141,39 +227,25 @@ int32_t tLDataIterOpen(struct SLDataIter **pIter, SDataFReader *pReader, int32_t
     code = tsdbReadSttBlk(pReader, iStt, pBlockLoadInfo->aSttBlk);
     if (code) {
       goto _exit;
+    } else {
+      size_t size = taosArrayGetSize(pBlockLoadInfo->aSttBlk);
+      SArray* pTmp = taosArrayInit(size, sizeof(SSttBlk));
+      for(int32_t i = 0; i < size; ++i) {
+        SSttBlk* p = taosArrayGet(pBlockLoadInfo->aSttBlk, i);
+        if (p->suid == suid) {
+          taosArrayPush(pTmp, p);
+        }
+      }
+
+      taosArrayDestroy(pBlockLoadInfo->aSttBlk);
+      pBlockLoadInfo->aSttBlk = pTmp;
     }
   }
 
   size_t size = taosArrayGetSize(pBlockLoadInfo->aSttBlk);
 
   // find the start block
-  int32_t index = -1;
-  if (!backward) {  // asc
-    for (int32_t i = 0; i < size; ++i) {
-      SSttBlk *p = taosArrayGet(pBlockLoadInfo->aSttBlk, i);
-      if (p->suid != suid) {
-        continue;
-      }
-
-      if (p->minUid <= uid && p->maxUid >= uid) {
-        index = i;
-        break;
-      }
-    }
-  } else {  // desc
-    for (int32_t i = size - 1; i >= 0; --i) {
-      SSttBlk *p = taosArrayGet(pBlockLoadInfo->aSttBlk, i);
-      if (p->suid != suid) {
-        continue;
-      }
-
-      if (p->minUid <= uid && p->maxUid >= uid) {
-        index = i;
-        break;
-      }
-    }
-  }
-
+  int32_t index = binarySearchForStartBlock(pBlockLoadInfo->aSttBlk->pData, size, uid, backward);
   (*pIter)->iSttBlk = index;
   if (index != -1) {
     (*pIter)->pSttBlk = taosArrayGet(pBlockLoadInfo->aSttBlk, (*pIter)->iSttBlk);
@@ -193,7 +265,7 @@ void tLDataIterNextBlock(SLDataIter *pIter) {
   pIter->iSttBlk += step;
 
   int32_t index = -1;
-  size_t  size = taosArrayGetSize(pIter->pBlockLoadInfo->aSttBlk);
+  size_t  size = pIter->pBlockLoadInfo->aSttBlk->size;//taosArrayGetSize(pIter->pBlockLoadInfo->aSttBlk);
   for (int32_t i = pIter->iSttBlk; i < size && i >= 0; i += step) {
     SSttBlk *p = taosArrayGet(pIter->pBlockLoadInfo->aSttBlk, i);
     if ((!pIter->backward) && p->minUid > pIter->uid) {
@@ -232,9 +304,8 @@ void tLDataIterNextBlock(SLDataIter *pIter) {
     }
   }
 
-  if (index == -1) {
-    pIter->pSttBlk = NULL;
-  } else {
+  pIter->pSttBlk = NULL;
+  if (index != -1) {
     pIter->pSttBlk = (SSttBlk *)taosArrayGet(pIter->pBlockLoadInfo->aSttBlk, pIter->iSttBlk);
   }
 }
@@ -247,18 +318,27 @@ static void findNextValidRow(SLDataIter *pIter) {
 
   SBlockData *pBlockData = loadBlockIfMissing(pIter);
 
+  // mostly we only need to find the start position for a given table
+  if ((((i == 0) && (!pIter->backward)) || (i == pBlockData->nRow - 1 && pIter->backward)) && pBlockData->aUid != NULL) {
+    i = binarySearchForStartRowIndex((uint64_t*)pBlockData->aUid, pBlockData->nRow, pIter->uid, pIter->backward);
+    if (i == -1) {
+      pIter->iRow = -1;
+      return;
+    }
+  }
+
   for (; i < pBlockData->nRow && i >= 0; i += step) {
     if (pBlockData->aUid != NULL) {
       if (!pIter->backward) {
-        if (pBlockData->aUid[i] < pIter->uid) {
+        /*if (pBlockData->aUid[i] < pIter->uid) {
           continue;
-        } else if (pBlockData->aUid[i] > pIter->uid) {
+        } else */if (pBlockData->aUid[i] > pIter->uid) {
           break;
         }
       } else {
-        if (pBlockData->aUid[i] > pIter->uid) {
+        /*if (pBlockData->aUid[i] > pIter->uid) {
           continue;
-        } else if (pBlockData->aUid[i] < pIter->uid) {
+        } else */if (pBlockData->aUid[i] < pIter->uid) {
           break;
         }
       }
diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index ea488d8f1c..dea17f92da 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -1238,6 +1238,38 @@ static bool tryCopyDistinctRowFromFileBlock(STsdbReader* pReader, SBlockData* pB
   return false;
 }
 
+static bool nextRowFromLastBlocks(SLastBlockReader* pLastBlockReader, STableBlockScanInfo* pBlockScanInfo) {
+  while (1) {
+    bool hasVal = tMergeTreeNext(&pLastBlockReader->mergeTree);
+    if (!hasVal) {
+      return false;
+    }
+
+    TSDBROW row = tMergeTreeGetRow(&pLastBlockReader->mergeTree);
+    TSDBKEY k = TSDBROW_KEY(&row);
+    if (!hasBeenDropped(pBlockScanInfo->delSkyline, &pBlockScanInfo->lastBlockDelIndex, &k, pLastBlockReader->order)) {
+      return true;
+    }
+  }
+}
+
+static bool tryCopyDistinctRowFromSttBlock(TSDBROW* fRow, SLastBlockReader* pLastBlockReader,
+                                           STableBlockScanInfo* pScanInfo, int64_t ts, STsdbReader* pReader) {
+  bool hasVal = nextRowFromLastBlocks(pLastBlockReader, pScanInfo);
+  if (hasVal) {
+    int64_t next1 = getCurrentKeyInLastBlock(pLastBlockReader);
+    if (next1 != ts) {
+      doAppendRowFromFileBlock(pReader->pResBlock, pReader, fRow->pBlockData, fRow->iRow);
+      return true;
+    }
+  } else {
+    doAppendRowFromFileBlock(pReader->pResBlock, pReader, fRow->pBlockData, fRow->iRow);
+    return true;
+  }
+
+  return false;
+}
+
 static FORCE_INLINE STSchema* doGetSchemaForTSRow(int32_t sversion, STsdbReader* pReader, uint64_t uid) {
   // always set the newest schema version in pReader->pSchema
   if (pReader->pSchema == NULL) {
@@ -1389,25 +1421,54 @@ static int32_t doMergeFileBlockAndLastBlock(SLastBlockReader* pLastBlockReader,
 
   STSRow*    pTSRow = NULL;
   SRowMerger merge = {0};
+  TSDBROW    fRow = tMergeTreeGetRow(&pLastBlockReader->mergeTree);
 
-  TSDBROW fRow = tMergeTreeGetRow(&pLastBlockReader->mergeTree);
-  tRowMergerInit(&merge, &fRow, pReader->pSchema);
-  doMergeRowsInLastBlock(pLastBlockReader, pBlockScanInfo, tsLastBlock, &merge);
+  // only last block exists
+  if ((!mergeBlockData) || (tsLastBlock != pBlockData->aTSKEY[pDumpInfo->rowIndex])) {
+    if (tryCopyDistinctRowFromSttBlock(&fRow, pLastBlockReader, pBlockScanInfo, tsLastBlock, pReader)) {
+      return TSDB_CODE_SUCCESS;
+    } else {
+      tRowMergerInit(&merge, &fRow, pReader->pSchema);
 
-  // merge with block data if ts == key
-  if (mergeBlockData && (tsLastBlock == pBlockData->aTSKEY[pDumpInfo->rowIndex])) {
-    doMergeRowsInFileBlocks(pBlockData, pBlockScanInfo, pReader, &merge);
+      TSDBROW fRow1 = tMergeTreeGetRow(&pLastBlockReader->mergeTree);
+      tRowMerge(&merge, &fRow1);
+      doMergeRowsInLastBlock(pLastBlockReader, pBlockScanInfo, tsLastBlock, &merge);
+
+      // merge with block data if ts == key
+      if (mergeBlockData && (tsLastBlock == pBlockData->aTSKEY[pDumpInfo->rowIndex])) {
+        doMergeRowsInFileBlocks(pBlockData, pBlockScanInfo, pReader, &merge);
+      }
+
+      int32_t code = tRowMergerGetRow(&merge, &pTSRow);
+      if (code != TSDB_CODE_SUCCESS) {
+        return code;
+      }
+
+      doAppendRowFromTSRow(pReader->pResBlock, pReader, pTSRow, pBlockScanInfo->uid);
+
+      taosMemoryFree(pTSRow);
+      tRowMergerClear(&merge);
+    }
+  } else {  // not merge block data
+    tRowMergerInit(&merge, &fRow, pReader->pSchema);
+    doMergeRowsInLastBlock(pLastBlockReader, pBlockScanInfo, tsLastBlock, &merge);
+
+    // merge with block data if ts == key
+    if (mergeBlockData && (tsLastBlock == pBlockData->aTSKEY[pDumpInfo->rowIndex])) {
+      doMergeRowsInFileBlocks(pBlockData, pBlockScanInfo, pReader, &merge);
+    }
+
+    int32_t code = tRowMergerGetRow(&merge, &pTSRow);
+    if (code != TSDB_CODE_SUCCESS) {
+      return code;
+    }
+
+    doAppendRowFromTSRow(pReader->pResBlock, pReader, pTSRow, pBlockScanInfo->uid);
+
+    taosMemoryFree(pTSRow);
+    tRowMergerClear(&merge);
   }
 
-  int32_t code = tRowMergerGetRow(&merge, &pTSRow);
-  if (code != TSDB_CODE_SUCCESS) {
-    return code;
-  }
-
-  doAppendRowFromTSRow(pReader->pResBlock, pReader, pTSRow, pBlockScanInfo->uid);
-
-  taosMemoryFree(pTSRow);
-  tRowMergerClear(&merge);
   return TSDB_CODE_SUCCESS;
 }
 
@@ -1858,21 +1919,6 @@ static bool isValidFileBlockRow(SBlockData* pBlockData, SFileBlockDumpInfo* pDum
 
 static bool outOfTimeWindow(int64_t ts, STimeWindow* pWindow) { return (ts > pWindow->ekey) || (ts < pWindow->skey); }
 
-static bool nextRowFromLastBlocks(SLastBlockReader* pLastBlockReader, STableBlockScanInfo* pBlockScanInfo) {
-  while (1) {
-    bool hasVal = tMergeTreeNext(&pLastBlockReader->mergeTree);
-    if (!hasVal) {
-      return false;
-    }
-
-    TSDBROW row = tMergeTreeGetRow(&pLastBlockReader->mergeTree);
-    TSDBKEY k = TSDBROW_KEY(&row);
-    if (!hasBeenDropped(pBlockScanInfo->delSkyline, &pBlockScanInfo->lastBlockDelIndex, &k, pLastBlockReader->order)) {
-      return true;
-    }
-  }
-}
-
 static bool initLastBlockReader(SLastBlockReader* pLBlockReader, STableBlockScanInfo* pScanInfo, STsdbReader* pReader) {
   // the last block reader has been initialized for this table.
   if (pLBlockReader->uid == pScanInfo->uid) {
@@ -1906,8 +1952,7 @@ static bool initLastBlockReader(SLastBlockReader* pLBlockReader, STableBlockScan
 
 static int64_t getCurrentKeyInLastBlock(SLastBlockReader* pLastBlockReader) {
   TSDBROW row = tMergeTreeGetRow(&pLastBlockReader->mergeTree);
-  TSDBKEY key = TSDBROW_KEY(&row);
-  return key.ts;
+  return TSDBROW_TS(&row);
 }
 
 static bool hasDataInLastBlock(SLastBlockReader* pLastBlockReader) { return pLastBlockReader->mergeTree.pIter != NULL; }
@@ -3080,11 +3125,16 @@ int32_t doAppendRowFromFileBlock(SSDataBlock* pResBlock, STsdbReader* pReader, S
     SColumnInfoData* pCol = taosArrayGet(pResBlock->pDataBlock, i);
     SColData*        pData = tBlockDataGetColDataByIdx(pBlockData, j);
 
+    if (pData->cid < pCol->info.colId) {
+      j += 1;
+      continue;
+    }
+
     if (pData->cid == pCol->info.colId) {
       tColDataGetValue(pData, rowIndex, &cv);
       doCopyColVal(pCol, outputRowIndex, i, &cv, pSupInfo);
       j += 1;
-    } else {  // the specified column does not exist in file block, fill with null data
+    } else if (pData->cid > pCol->info.colId) {  // the specified column does not exist in file block, fill with null data
       colDataAppendNULL(pCol, outputRowIndex);
     }
 
@@ -3206,11 +3256,18 @@ int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, SArray* pTabl
     }
   }
 
+  // NOTE: the endVersion in pCond is the data version not schema version, so pCond->endVersion is not correct here.
   if (pCond->suid != 0) {
-    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, pReader->suid, pCond->endVersion);
+    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, pReader->suid, /*pCond->endVersion*/ -1);
+    if (pReader->pSchema == NULL) {
+      tsdbError("failed to get table schema, suid:%"PRIu64", ver:%"PRId64" , %s", pReader->suid, -1, pReader->idStr);
+    }
   } else if (taosArrayGetSize(pTableList) > 0) {
     STableKeyInfo* pKey = taosArrayGet(pTableList, 0);
-    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, pKey->uid, pCond->endVersion);
+    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, pKey->uid, /*pCond->endVersion*/ -1);
+    if (pReader->pSchema == NULL) {
+      tsdbError("failed to get table schema, uid:%"PRIu64", ver:%"PRId64" , %s", pKey->uid, -1, pReader->idStr);
+    }
   }
 
   int32_t numOfTables = taosArrayGetSize(pTableList);
diff --git a/tests/system-test/fulltest.sh b/tests/system-test/fulltest.sh
index 11df13d451..8987ba3bbd 100755
--- a/tests/system-test/fulltest.sh
+++ b/tests/system-test/fulltest.sh
@@ -333,7 +333,7 @@ python3 ./test.py -f 7-tmq/stbTagFilter-1ctb.py
 python3 ./test.py -f 7-tmq/dataFromTsdbNWal.py
 python3 ./test.py -f 7-tmq/dataFromTsdbNWal-multiCtb.py
 python3 ./test.py -f 7-tmq/tmq_taosx.py
-# python3 ./test.py -f 7-tmq/stbTagFilter-multiCtb.py
+python3 ./test.py -f 7-tmq/stbTagFilter-multiCtb.py
 
 #------------querPolicy  2-----------