diff --git a/source/dnode/vnode/inc/vnode.h b/source/dnode/vnode/inc/vnode.h
index fb2c2f4be3..aecfb9c3e5 100644
--- a/source/dnode/vnode/inc/vnode.h
+++ b/source/dnode/vnode/inc/vnode.h
@@ -162,7 +162,6 @@ int32_t     metaTbCursorPrev(SMTbCursor *pTbCur, ETableType jumpTableType);
 #endif
 
 // tsdb
-// typedef struct STsdb STsdb;
 typedef struct STsdbReader STsdbReader;
 
 #define TSDB_DEFAULT_STT_FILE  8
diff --git a/source/dnode/vnode/src/inc/tsdb.h b/source/dnode/vnode/src/inc/tsdb.h
index 2a85b191a4..8f6f9daf84 100644
--- a/source/dnode/vnode/src/inc/tsdb.h
+++ b/source/dnode/vnode/src/inc/tsdb.h
@@ -705,7 +705,6 @@ typedef struct SSttBlockLoadInfo {
 typedef struct SMergeTree {
   int8_t             backward;
   SRBTree            rbt;
-  SArray            *pIterList;
   SLDataIter        *pIter;
   bool               destroyLoadInfo;
   SSttBlockLoadInfo *pLoadInfo;
@@ -751,9 +750,25 @@ struct SDiskDataBuilder {
   SBlkInfo     bi;
 };
 
+typedef struct SLDataIter {
+  SRBTreeNode        node;
+  SSttBlk           *pSttBlk;
+  SDataFReader      *pReader;
+  int32_t            iStt;
+  int8_t             backward;
+  int32_t            iSttBlk;
+  int32_t            iRow;
+  SRowInfo           rInfo;
+  uint64_t           uid;
+  STimeWindow        timeWindow;
+  SVersionRange      verRange;
+  SSttBlockLoadInfo *pBlockLoadInfo;
+  bool               ignoreEarlierTs;
+} SLDataIter;
+
 int32_t tMergeTreeOpen(SMergeTree *pMTree, int8_t backward, SDataFReader *pFReader, uint64_t suid, uint64_t uid,
                        STimeWindow *pTimeWindow, SVersionRange *pVerRange, SSttBlockLoadInfo *pBlockLoadInfo,
-                       bool destroyLoadInfo, const char *idStr, bool strictTimeRange);
+                       bool destroyLoadInfo, const char *idStr, bool strictTimeRange, SLDataIter* pLDataIter);
 void    tMergeTreeAddIter(SMergeTree *pMTree, SLDataIter *pIter);
 bool    tMergeTreeNext(SMergeTree *pMTree);
 bool    tMergeTreeIgnoreEarlierTs(SMergeTree *pMTree);
@@ -782,6 +797,7 @@ typedef struct SCacheRowsReader {
   STableKeyInfo     *pTableList;  // table id list
   int32_t            numOfTables;
   SSttBlockLoadInfo *pLoadInfo;
+  SLDataIter        *pDataIter;
   STsdbReadSnap     *pReadSnap;
   SDataFReader      *pDataFReader;
   SDataFReader      *pDataFReaderLast;
diff --git a/source/dnode/vnode/src/tsdb/tsdbCache.c b/source/dnode/vnode/src/tsdb/tsdbCache.c
index 3c7edd931b..42f332c54a 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCache.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCache.c
@@ -598,6 +598,7 @@ typedef struct {
   SMergeTree         mergeTree;
   SMergeTree        *pMergeTree;
   SSttBlockLoadInfo *pLoadInfo;
+  SLDataIter*        pDataIter;
   int64_t            lastTs;
 } SFSLastNextRowIter;
 
@@ -645,7 +646,7 @@ static int32_t getNextRowFromFSLast(void *iter, TSDBROW **ppRow, bool *pIgnoreEa
       }
       tMergeTreeOpen(&state->mergeTree, 1, *state->pDataFReader, state->suid, state->uid,
                      &(STimeWindow){.skey = state->lastTs, .ekey = TSKEY_MAX},
-                     &(SVersionRange){.minVer = 0, .maxVer = UINT64_MAX}, state->pLoadInfo, false, NULL, true);
+                     &(SVersionRange){.minVer = 0, .maxVer = UINT64_MAX}, state->pLoadInfo, false, NULL, true, state->pDataIter);
       state->pMergeTree = &state->mergeTree;
       state->state = SFSLASTNEXTROW_BLOCKROW;
     }
@@ -1211,7 +1212,7 @@ typedef struct {
 } CacheNextRowIter;
 
 static int32_t nextRowIterOpen(CacheNextRowIter *pIter, tb_uid_t uid, STsdb *pTsdb, STSchema *pTSchema, tb_uid_t suid,
-                               SSttBlockLoadInfo *pLoadInfo, STsdbReadSnap *pReadSnap, SDataFReader **pDataFReader,
+                               SSttBlockLoadInfo *pLoadInfo, SLDataIter* pLDataIter, STsdbReadSnap *pReadSnap, SDataFReader **pDataFReader,
                                SDataFReader **pDataFReaderLast, int64_t lastTs) {
   int code = 0;
 
@@ -1274,6 +1275,7 @@ static int32_t nextRowIterOpen(CacheNextRowIter *pIter, tb_uid_t uid, STsdb *pTs
   pIter->fsLastState.pLoadInfo = pLoadInfo;
   pIter->fsLastState.pDataFReader = pDataFReaderLast;
   pIter->fsLastState.lastTs = lastTs;
+  pIter->fsLastState.pDataIter = pLDataIter;
 
   pIter->fsState.state = SFSNEXTROW_FS;
   pIter->fsState.pTsdb = pTsdb;
@@ -1465,7 +1467,7 @@ static int32_t mergeLastRow(tb_uid_t uid, STsdb *pTsdb, bool *dup, SArray **ppCo
   TSKEY lastRowTs = TSKEY_MAX;
 
   CacheNextRowIter iter = {0};
-  nextRowIterOpen(&iter, uid, pTsdb, pTSchema, pr->suid, pr->pLoadInfo, pr->pReadSnap, &pr->pDataFReader,
+  nextRowIterOpen(&iter, uid, pTsdb, pTSchema, pr->suid, pr->pLoadInfo, pr->pDataIter, pr->pReadSnap, &pr->pDataFReader,
                   &pr->pDataFReaderLast, pr->lastTs);
 
   do {
@@ -1622,7 +1624,7 @@ static int32_t mergeLast(tb_uid_t uid, STsdb *pTsdb, SArray **ppLastArray, SCach
   TSKEY lastRowTs = TSKEY_MAX;
 
   CacheNextRowIter iter = {0};
-  nextRowIterOpen(&iter, uid, pTsdb, pTSchema, pr->suid, pr->pLoadInfo, pr->pReadSnap, &pr->pDataFReader,
+  nextRowIterOpen(&iter, uid, pTsdb, pTSchema, pr->suid, pr->pLoadInfo, pr->pDataIter, pr->pReadSnap, &pr->pDataFReader,
                   &pr->pDataFReaderLast, pr->lastTs);
 
   do {
diff --git a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
index 95981c2f08..64d30c77a3 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
@@ -187,13 +187,21 @@ int32_t tsdbCacherowsReaderOpen(void* pVnode, int32_t type, void* pTableIdList,
     }
   }
 
-  int32_t numOfStt = ((SVnode*)pVnode)->config.sttTrigger;
+  SVnodeCfg* pCfg = &((SVnode*)pVnode)->config;
+
+  int32_t numOfStt = pCfg->sttTrigger;
   p->pLoadInfo = tCreateLastBlockLoadInfo(p->pSchema, NULL, 0, numOfStt);
   if (p->pLoadInfo == NULL) {
     tsdbCacherowsReaderClose(p);
     return TSDB_CODE_OUT_OF_MEMORY;
   }
 
+  p->pDataIter = taosMemoryCalloc(pCfg->sttTrigger, sizeof(SLDataIter));
+  if (p->pDataIter == NULL) {
+    tsdbCacherowsReaderClose(p);
+    return TSDB_CODE_OUT_OF_MEMORY;
+  }
+
   p->idstr = taosStrdup(idstr);
   taosThreadMutexInit(&p->readerMutex, NULL);
 
@@ -215,6 +223,7 @@ void* tsdbCacherowsReaderClose(void* pReader) {
     taosMemoryFree(p->pSchema);
   }
 
+  taosMemoryFreeClear(p->pDataIter);
   taosMemoryFree(p->pCurrSchema);
 
   destroyLastBlockLoadInfo(p->pLoadInfo);
diff --git a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
index eb383df48d..e354a50253 100644
--- a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
+++ b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
@@ -16,22 +16,6 @@
 #include "tsdb.h"
 
 // SLDataIter =================================================
-struct SLDataIter {
-  SRBTreeNode        node;
-  SSttBlk           *pSttBlk;
-  SDataFReader      *pReader;
-  int32_t            iStt;
-  int8_t             backward;
-  int32_t            iSttBlk;
-  int32_t            iRow;
-  SRowInfo           rInfo;
-  uint64_t           uid;
-  STimeWindow        timeWindow;
-  SVersionRange      verRange;
-  SSttBlockLoadInfo *pBlockLoadInfo;
-  bool               ignoreEarlierTs;
-};
-
 SSttBlockLoadInfo *tCreateLastBlockLoadInfo(STSchema *pSchema, int16_t *colList, int32_t numOfCols,
                                             int32_t numOfSttTrigger) {
   SSttBlockLoadInfo *pLoadInfo = taosMemoryCalloc(numOfSttTrigger, sizeof(SSttBlockLoadInfo));
@@ -268,25 +252,19 @@ static int32_t binarySearchForStartRowIndex(uint64_t *uidList, int32_t num, uint
   }
 }
 
-int32_t tLDataIterOpen(struct SLDataIter **pIter, SDataFReader *pReader, int32_t iStt, int8_t backward, uint64_t suid,
+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,
                        const char *idStr, bool strictTimeRange) {
   int32_t code = TSDB_CODE_SUCCESS;
 
-  *pIter = taosMemoryCalloc(1, sizeof(SLDataIter));
-  if (*pIter == NULL) {
-    code = TSDB_CODE_OUT_OF_MEMORY;
-    goto _exit;
-  }
+  pIter->uid = uid;
+  pIter->pReader = pReader;
+  pIter->iStt = iStt;
+  pIter->backward = backward;
+  pIter->verRange = *pRange;
+  pIter->timeWindow = *pTimeWindow;
 
-  (*pIter)->uid = uid;
-  (*pIter)->pReader = pReader;
-  (*pIter)->iStt = iStt;
-  (*pIter)->backward = backward;
-  (*pIter)->verRange = *pRange;
-  (*pIter)->timeWindow = *pTimeWindow;
-
-  (*pIter)->pBlockLoadInfo = pBlockLoadInfo;
+  pIter->pBlockLoadInfo = pBlockLoadInfo;
 
   if (!pBlockLoadInfo->sttBlockLoaded) {
     int64_t st = taosGetTimestampUs();
@@ -294,7 +272,7 @@ int32_t tLDataIterOpen(struct SLDataIter **pIter, SDataFReader *pReader, int32_t
 
     code = tsdbReadSttBlk(pReader, iStt, pBlockLoadInfo->aSttBlk);
     if (code) {
-      goto _exit;
+      return code;
     }
 
     // only apply to the child tables, ordinary tables will not incur this filter procedure.
@@ -310,7 +288,7 @@ int32_t tLDataIterOpen(struct SLDataIter **pIter, SDataFReader *pReader, int32_t
           // no qualified stt block existed
           taosArrayClear(pBlockLoadInfo->aSttBlk);
 
-          (*pIter)->iSttBlk = -1;
+          pIter->iSttBlk = -1;
           double el = (taosGetTimestampUs() - st) / 1000.0;
           tsdbDebug("load the last file info completed, elapsed time:%.2fms, %s", el, idStr);
           return code;
@@ -343,31 +321,27 @@ int32_t tLDataIterOpen(struct SLDataIter **pIter, SDataFReader *pReader, int32_t
   size_t size = taosArrayGetSize(pBlockLoadInfo->aSttBlk);
 
   // find the start block
-  (*pIter)->iSttBlk = binarySearchForStartBlock(pBlockLoadInfo->aSttBlk->pData, size, uid, backward);
-  if ((*pIter)->iSttBlk != -1) {
-    (*pIter)->pSttBlk = taosArrayGet(pBlockLoadInfo->aSttBlk, (*pIter)->iSttBlk);
-    (*pIter)->iRow = ((*pIter)->backward) ? (*pIter)->pSttBlk->nRow : -1;
+  pIter->iSttBlk = binarySearchForStartBlock(pBlockLoadInfo->aSttBlk->pData, size, uid, backward);
+  if (pIter->iSttBlk != -1) {
+    pIter->pSttBlk = taosArrayGet(pBlockLoadInfo->aSttBlk, pIter->iSttBlk);
+    pIter->iRow = (pIter->backward) ? pIter->pSttBlk->nRow : -1;
 
-    if ((!backward) && ((strictTimeRange && (*pIter)->pSttBlk->minKey >= (*pIter)->timeWindow.ekey) ||
-                        (!strictTimeRange && (*pIter)->pSttBlk->minKey > (*pIter)->timeWindow.ekey))) {
-      (*pIter)->pSttBlk = NULL;
+    if ((!backward) && ((strictTimeRange && pIter->pSttBlk->minKey >= pIter->timeWindow.ekey) ||
+                        (!strictTimeRange && pIter->pSttBlk->minKey > pIter->timeWindow.ekey))) {
+      pIter->pSttBlk = NULL;
     }
 
-    if (backward && ((strictTimeRange && (*pIter)->pSttBlk->maxKey <= (*pIter)->timeWindow.skey) ||
-                     (!strictTimeRange && (*pIter)->pSttBlk->maxKey < (*pIter)->timeWindow.skey))) {
-      (*pIter)->pSttBlk = NULL;
-      (*pIter)->ignoreEarlierTs = true;
+    if (backward && ((strictTimeRange && pIter->pSttBlk->maxKey <= pIter->timeWindow.skey) ||
+                     (!strictTimeRange && pIter->pSttBlk->maxKey < pIter->timeWindow.skey))) {
+      pIter->pSttBlk = NULL;
+      pIter->ignoreEarlierTs = true;
     }
   }
 
   return code;
-
-_exit:
-  taosMemoryFree(*pIter);
-  return code;
 }
 
-void tLDataIterClose(SLDataIter *pIter) { taosMemoryFree(pIter); }
+void tLDataIterClose(SLDataIter *pIter) { /*taosMemoryFree(pIter); */}
 
 void tLDataIterNextBlock(SLDataIter *pIter, const char *idStr) {
   int32_t step = pIter->backward ? -1 : 1;
@@ -594,43 +568,38 @@ static FORCE_INLINE int32_t tLDataIterDescCmprFn(const SRBTreeNode *p1, const SR
 
 int32_t tMergeTreeOpen(SMergeTree *pMTree, int8_t backward, SDataFReader *pFReader, uint64_t suid, uint64_t uid,
                        STimeWindow *pTimeWindow, SVersionRange *pVerRange, SSttBlockLoadInfo *pBlockLoadInfo,
-                       bool destroyLoadInfo, const char *idStr, bool strictTimeRange) {
+                       bool destroyLoadInfo, const char *idStr, bool strictTimeRange, SLDataIter* pLDataIter) {
+  int32_t code = TSDB_CODE_SUCCESS;
+
   pMTree->backward = backward;
   pMTree->pIter = NULL;
-  pMTree->pIterList = taosArrayInit(4, POINTER_BYTES);
-  if (pMTree->pIterList == NULL) {
-    return TSDB_CODE_OUT_OF_MEMORY;
-  }
-
   pMTree->idStr = idStr;
+
   if (!pMTree->backward) {  // asc
     tRBTreeCreate(&pMTree->rbt, tLDataIterCmprFn);
   } else {  // desc
     tRBTreeCreate(&pMTree->rbt, tLDataIterDescCmprFn);
   }
-  int32_t code = TSDB_CODE_SUCCESS;
 
   pMTree->pLoadInfo = pBlockLoadInfo;
   pMTree->destroyLoadInfo = destroyLoadInfo;
   pMTree->ignoreEarlierTs = false;
 
   for (int32_t i = 0; i < pFReader->pSet->nSttF; ++i) {  // open all last file
-    struct SLDataIter *pIter = NULL;
-    code = tLDataIterOpen(&pIter, pFReader, i, pMTree->backward, suid, uid, pTimeWindow, pVerRange,
+    memset(&pLDataIter[i], 0, sizeof(SLDataIter));
+    code = tLDataIterOpen(&pLDataIter[i], pFReader, i, pMTree->backward, suid, uid, pTimeWindow, pVerRange,
                           &pMTree->pLoadInfo[i], pMTree->idStr, strictTimeRange);
     if (code != TSDB_CODE_SUCCESS) {
       goto _end;
     }
 
-    bool hasVal = tLDataIterNextRow(pIter, pMTree->idStr);
+    bool hasVal = tLDataIterNextRow(&pLDataIter[i], pMTree->idStr);
     if (hasVal) {
-      taosArrayPush(pMTree->pIterList, &pIter);
-      tMergeTreeAddIter(pMTree, pIter);
+      tMergeTreeAddIter(pMTree, &pLDataIter[i]);
     } else {
       if (!pMTree->ignoreEarlierTs) {
-        pMTree->ignoreEarlierTs = pIter->ignoreEarlierTs;
+        pMTree->ignoreEarlierTs = pLDataIter[i].ignoreEarlierTs;
       }
-      tLDataIterClose(pIter);
     }
   }
 
@@ -681,15 +650,7 @@ bool tMergeTreeNext(SMergeTree *pMTree) {
 TSDBROW tMergeTreeGetRow(SMergeTree *pMTree) { return pMTree->pIter->rInfo.row; }
 
 void tMergeTreeClose(SMergeTree *pMTree) {
-  size_t size = taosArrayGetSize(pMTree->pIterList);
-  for (int32_t i = 0; i < size; ++i) {
-    SLDataIter *pIter = taosArrayGetP(pMTree->pIterList, i);
-    tLDataIterClose(pIter);
-  }
-
-  pMTree->pIterList = taosArrayDestroy(pMTree->pIterList);
   pMTree->pIter = NULL;
-
   if (pMTree->destroyLoadInfo) {
     pMTree->pLoadInfo = destroyLastBlockLoadInfo(pMTree->pLoadInfo);
     pMTree->destroyLoadInfo = false;
diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index 5bd41dd86f..3aa3bdbd94 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -156,6 +156,7 @@ typedef struct SReaderStatus {
   SBlockData            fileBlockData;
   SFilesetIter          fileIter;
   SDataBlockIter        blockIter;
+  SLDataIter*           pLDataIter;
 } SReaderStatus;
 
 typedef struct SBlockInfoBuf {
@@ -185,7 +186,6 @@ struct STsdbReader {
   STsdbReadSnap*     pReadSnap;
   SIOCostSummary     cost;
   STSchema*          pSchema;  // the newest version schema
-  //  STSchema*          pMemSchema;   // the previous schema for in-memory data, to avoid load schema too many times
   SSHashObj*    pSchemaMap;   // keep the retrieved schema info, to avoid the overhead by repeatly load schema
   SDataFReader* pFileReader;  // the file reader
   SDelFReader*  pDelFReader;  // the del file reader
@@ -741,6 +741,7 @@ static int32_t tsdbReaderCreate(SVnode* pVnode, SQueryTableDataCond* pCond, STsd
   pReader->type = pCond->type;
   pReader->window = updateQueryTimeWindow(pReader->pTsdb, &pCond->twindows);
   pReader->blockInfoBuf.numPerBucket = 1000;  // 1000 tables per bucket
+  pReader->status.pLDataIter = taosMemoryCalloc(pVnode->config.sttTrigger, sizeof(SLDataIter));
 
   if (pReader->pResBlock == NULL) {
     pReader->freeBlock = true;
@@ -2547,7 +2548,7 @@ static bool initLastBlockReader(SLastBlockReader* pLBlockReader, STableBlockScan
             pScanInfo->uid, pReader->idStr);
   int32_t code = tMergeTreeOpen(&pLBlockReader->mergeTree, (pLBlockReader->order == TSDB_ORDER_DESC),
                                 pReader->pFileReader, pReader->suid, pScanInfo->uid, &w, &pLBlockReader->verRange,
-                                pLBlockReader->pInfo, false, pReader->idStr, false);
+                                pLBlockReader->pInfo, false, pReader->idStr, false, pReader->status.pLDataIter);
   if (code != TSDB_CODE_SUCCESS) {
     return false;
   }