diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index 92edaef5ec..717b76046a 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -79,8 +79,8 @@ typedef struct SIOCostSummary {
   int64_t composedBlocks;
   double  buildComposedBlockTime;
   double  createScanInfoList;
-  double  getTbFromMemTime;
-  double  getTbFromIMemTime;
+//  double  getTbFromMemTime;
+//  double  getTbFromIMemTime;
   double  initDelSkylineIterTime;
 } SIOCostSummary;
 
@@ -1558,8 +1558,7 @@ static bool fileBlockShouldLoad(STsdbReader* pReader, SFileDataBlockInfo* pBlock
 
   // log the reason why load the datablock for profile
   if (loadDataBlock) {
-    tsdbDebug("%p uid:%" PRIu64
-              " need to load the datablock, overlapwithneighborblock:%d, hasDup:%d, partiallyRequired:%d, "
+    tsdbDebug("%p uid:%" PRIu64 " need to load the datablock, overlapneighbor:%d, hasDup:%d, partiallyRequired:%d, "
               "overlapWithKey:%d, greaterThanBuf:%d, overlapWithDel:%d, overlapWithlastBlock:%d, %s",
               pReader, pBlockInfo->uid, info.overlapWithNeighborBlock, info.hasDupTs, info.partiallyRequired,
               info.overlapWithKeyInBuf, info.moreThanCapcity, info.overlapWithDelInfo, info.overlapWithLastBlock,
@@ -2188,9 +2187,7 @@ static int32_t initMemDataIterator(STableBlockScanInfo* pBlockScanInfo, STsdbRea
 
   STbData* d = NULL;
   if (pReader->pReadSnap->pMem != NULL) {
-    st = taosGetTimestampUs();
     d = tsdbGetTbDataFromMemTable(pReader->pReadSnap->pMem, pReader->suid, pBlockScanInfo->uid);
-    pReader->cost.getTbFromMemTime += (taosGetTimestampUs() - st) / 1000.0;
     if (d != NULL) {
       code = tsdbTbDataIterCreate(d, &startKey, backward, &pBlockScanInfo->iter.iter);
       if (code == TSDB_CODE_SUCCESS) {
@@ -2211,9 +2208,7 @@ static int32_t initMemDataIterator(STableBlockScanInfo* pBlockScanInfo, STsdbRea
 
   STbData* di = NULL;
   if (pReader->pReadSnap->pIMem != NULL) {
-    st = taosGetTimestampUs();
     di = tsdbGetTbDataFromMemTable(pReader->pReadSnap->pIMem, pReader->suid, pBlockScanInfo->uid);
-    pReader->cost.getTbFromIMemTime += (taosGetTimestampUs() - st) / 1000.0;
     if (di != NULL) {
       code = tsdbTbDataIterCreate(di, &startKey, backward, &pBlockScanInfo->iiter.iter);
       if (code == TSDB_CODE_SUCCESS) {
@@ -2608,21 +2603,39 @@ _err:
 }
 
 TSDBKEY getCurrentKeyInBuf(STableBlockScanInfo* pScanInfo, STsdbReader* pReader) {
-  TSDBKEY  key = {.ts = TSKEY_INITIAL_VAL};
+  bool asc = ASCENDING_TRAVERSE(pReader->order);
+//  TSKEY initialVal = asc? TSKEY_MIN:TSKEY_MAX;
+
+  TSDBKEY  key = {.ts = TSKEY_INITIAL_VAL}, ikey = {.ts = TSKEY_INITIAL_VAL};
+
+  bool hasKey = false, hasIKey = false;
   TSDBROW* pRow = getValidMemRow(&pScanInfo->iter, pScanInfo->delSkyline, pReader);
   if (pRow != NULL) {
+    hasKey = true;
     key = TSDBROW_KEY(pRow);
   }
 
-  pRow = getValidMemRow(&pScanInfo->iiter, pScanInfo->delSkyline, pReader);
-  if (pRow != NULL) {
-    TSDBKEY k = TSDBROW_KEY(pRow);
-    if (key.ts > k.ts) {
-      key = k;
-    }
+  TSDBROW* pIRow = getValidMemRow(&pScanInfo->iiter, pScanInfo->delSkyline, pReader);
+  if (pIRow != NULL) {
+    hasIKey = true;
+    ikey = TSDBROW_KEY(pIRow);
   }
 
-  return key;
+  if (hasKey) {
+    if (hasIKey) { // has data in mem & imem
+      if (asc) {
+        return key.ts <= ikey.ts ? key : ikey;
+      } else  {
+        return key.ts <= ikey.ts ? ikey: key;
+      }
+    } else {  // no data in imem
+      return key;
+    }
+  } else {
+    // no data in mem & imem, return the initial value
+    // only imem has data, return ikey
+    return ikey;
+  }
 }
 
 static int32_t moveToNextFile(STsdbReader* pReader, SBlockNumber* pBlockNum) {
@@ -2851,21 +2864,14 @@ static int32_t doBuildDataBlock(STsdbReader* pReader) {
 
   ASSERT(pBlockInfo != NULL);
 
-  //  if (pBlockInfo != NULL) {
   pScanInfo = *(STableBlockScanInfo**)taosHashGet(pReader->status.pTableMap, &pBlockInfo->uid, sizeof(pBlockInfo->uid));
-  //  } else {
-  //    pScanInfo = *pReader->status.pTableIter;
-  //  }
-
   if (pScanInfo == NULL) {
     tsdbError("failed to get table scan-info, %s", pReader->idStr);
     code = TSDB_CODE_INVALID_PARA;
     return code;
   }
 
-  //  if (pBlockInfo != NULL) {
   pBlock = getCurrentBlock(pBlockIter);
-  //  }
 
   initLastBlockReader(pLastBlockReader, pScanInfo, pReader);
   TSDBKEY keyInBuf = getCurrentKeyInBuf(pScanInfo, pReader);
@@ -4015,12 +4021,11 @@ void tsdbReaderClose(STsdbReader* pReader) {
       " SMA-time:%.2f ms, fileBlocks:%" PRId64
       ", fileBlocks-load-time:%.2f ms, "
       "build in-memory-block-time:%.2f ms, lastBlocks:%" PRId64 ", lastBlocks-time:%.2f ms, composed-blocks:%" PRId64
-      ", composed-blocks-time:%.2fms, STableBlockScanInfo size:%.2f Kb, creatTime:%.2f ms,"
-      ", getTbFromMem-time:%.2f ms, getTbFromIMem-time:%.2f ms, initDelSkylineIterTime:%.2f ms, %s",
+      ", composed-blocks-time:%.2fms, STableBlockScanInfo size:%.2f Kb, createTime:%.2f ms,initDelSkylineIterTime:%.2f ms, %s",
       pReader, pCost->headFileLoad, pCost->headFileLoadTime, pCost->smaDataLoad, pCost->smaLoadTime, pCost->numOfBlocks,
       pCost->blockLoadTime, pCost->buildmemBlock, pCost->lastBlockLoad, pCost->lastBlockLoadTime, pCost->composedBlocks,
       pCost->buildComposedBlockTime, numOfTables * sizeof(STableBlockScanInfo) / 1000.0, pCost->createScanInfoList,
-      pCost->getTbFromMemTime, pCost->getTbFromIMemTime, pCost->initDelSkylineIterTime, pReader->idStr);
+      pCost->initDelSkylineIterTime, pReader->idStr);
 
   taosMemoryFree(pReader->idStr);
   taosMemoryFree(pReader->pSchema);