diff --git a/source/dnode/vnode/src/inc/tsdb.h b/source/dnode/vnode/src/inc/tsdb.h
index 4c513371f5..65293a220d 100644
--- a/source/dnode/vnode/src/inc/tsdb.h
+++ b/source/dnode/vnode/src/inc/tsdb.h
@@ -723,6 +723,9 @@ void              *destroyLastBlockLoadInfo(SSttBlockLoadInfo *pLoadInfo);
 
 // tsdbCache ==============================================================================================
 typedef struct SCacheRowsReader {
+  STsdb             *pTsdb;
+  SVersionRange      verRange;
+  TdThreadMutex      readerMutex;
   SVnode            *pVnode;
   STSchema          *pSchema;
   uint64_t           uid;
diff --git a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
index 86cc00568e..aef402acaf 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
@@ -108,6 +108,8 @@ int32_t tsdbCacherowsReaderOpen(void* pVnode, int32_t type, SArray* pTableIdList
 
   p->type = type;
   p->pVnode = pVnode;
+  p->pTsdb = p->pVnode->pTsdb;
+  p->verRange = (SVersionRange){.minVer = 0, .maxVer = UINT64_MAX};
   p->numOfCols = numOfCols;
   p->suid = suid;
 
@@ -142,6 +144,8 @@ int32_t tsdbCacherowsReaderOpen(void* pVnode, int32_t type, SArray* pTableIdList
     return TSDB_CODE_OUT_OF_MEMORY;
   }
 
+  taosThreadMutexInit(&p->readerMutex, NULL);
+
   *pReader = p;
   return TSDB_CODE_SUCCESS;
 }
@@ -160,6 +164,8 @@ void* tsdbCacherowsReaderClose(void* pReader) {
 
   destroyLastBlockLoadInfo(p->pLoadInfo);
 
+  taosThreadMutexDestroy(&p->readerMutex);
+
   taosMemoryFree(pReader);
   return NULL;
 }
@@ -195,8 +201,15 @@ static void freeItem(void* pItem) {
 }
 
 static int32_t tsdbCacheQueryReseek(void* pQHandle) {
-  int32_t code = 0;
+  int32_t           code = 0;
+  SCacheRowsReader* pReader = pQHandle;
 
+  taosThreadMutexLock(&pReader->readerMutex);
+
+  // pause current reader's state if not paused, save ts & version for resuming
+  // just wait for the big all tables' snapshot untaking for now
+
+  taosThreadMutexUnlock(&pReader->readerMutex);
   return code;
 }
 
@@ -243,7 +256,8 @@ int32_t tsdbRetrieveCacheRows(void* pReader, SSDataBlock* pResBlock, const int32
     taosArrayPush(pLastCols, &p);
   }
 
-  tsdbTakeReadSnap(NULL, tsdbCacheQueryReseek, &pr->pReadSnap);
+  taosThreadMutexLock(&pr->readerMutex);
+  tsdbTakeReadSnap((STsdbReader*)pr, tsdbCacheQueryReseek, &pr->pReadSnap);
   pr->pDataFReader = NULL;
   pr->pDataFReaderLast = NULL;
 
@@ -344,7 +358,8 @@ _end:
   tsdbDataFReaderClose(&pr->pDataFReaderLast);
   tsdbDataFReaderClose(&pr->pDataFReader);
 
-  tsdbUntakeReadSnap(NULL, pr->pReadSnap);
+  tsdbUntakeReadSnap((STsdbReader*)pr, pr->pReadSnap);
+  taosThreadMutexUnlock(&pr->readerMutex);
 
   for (int32_t j = 0; j < pr->numOfCols; ++j) {
     taosMemoryFree(pRes[j]);
diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index 4808956693..92d5515430 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -142,6 +142,9 @@ typedef struct SReaderStatus {
 
 struct STsdbReader {
   STsdb*             pTsdb;
+  SVersionRange      verRange;
+  TdThreadMutex      readerMutex;
+  bool               suspended;
   uint64_t           suid;
   int16_t            order;
   STimeWindow        window;  // the primary query time window that applies to all queries
@@ -156,7 +159,6 @@ struct STsdbReader {
   STSchema*          pSchema;     // the newest version schema
   STSchema*          pMemSchema;  // the previous schema for in-memory data, to avoid load schema too many times
   SDataFReader*      pFileReader;
-  SVersionRange      verRange;
 
   int32_t      step;
   STsdbReader* innerReader[2];
@@ -522,6 +524,8 @@ static int32_t tsdbReaderCreate(SVnode* pVnode, SQueryTableDataCond* pCond, STsd
 
   setColumnIdSlotList(pReader, pReader->pResBlock);
 
+  taosThreadMutexInit(&pReader->readerMutex, NULL);
+
   *ppReader = pReader;
   return code;
 
@@ -613,12 +617,26 @@ static int32_t doLoadFileBlock(STsdbReader* pReader, SArray* pIndexList, SBlockN
     tsdbReadDataBlk(pReader->pFileReader, pBlockIdx, &pScanInfo->mapData);
 
     sizeInDisk += pScanInfo->mapData.nData;
+
+    int32_t     step = ASCENDING_TRAVERSE(pReader->order) ? 1 : -1;
+    STimeWindow w = pReader->window;
+    if (ASCENDING_TRAVERSE(pReader->order)) {
+      w.skey = pScanInfo->lastKey + step;
+    } else {
+      w.ekey = pScanInfo->lastKey + step;
+    }
+
+    if (isEmptyQueryTimeWindow(&w)) {
+      continue;
+    }
+
     for (int32_t j = 0; j < pScanInfo->mapData.nItem; ++j) {
       SDataBlk block = {0};
       tMapDataGetItemByIdx(&pScanInfo->mapData, j, &block, tGetDataBlk);
 
       // 1. time range check
-      if (block.minKey.ts > pReader->window.ekey || block.maxKey.ts < pReader->window.skey) {
+      // if (block.minKey.ts > pReader->window.ekey || block.maxKey.ts < pReader->window.skey) {
+      if (block.minKey.ts > w.ekey || block.maxKey.ts < w.skey) {
         continue;
       }
 
@@ -2018,9 +2036,11 @@ static int32_t initMemDataIterator(STableBlockScanInfo* pBlockScanInfo, STsdbRea
 
   TSDBKEY startKey = {0};
   if (ASCENDING_TRAVERSE(pReader->order)) {
-    startKey = (TSDBKEY){.ts = pReader->window.skey, .version = pReader->verRange.minVer};
+    // startKey = (TSDBKEY){.ts = pReader->window.skey, .version = pReader->verRange.minVer};
+    startKey = (TSDBKEY){.ts = pBlockScanInfo->lastKey + 1, .version = pReader->verRange.minVer};
   } else {
-    startKey = (TSDBKEY){.ts = pReader->window.ekey, .version = pReader->verRange.maxVer};
+    // startKey = (TSDBKEY){.ts = pReader->window.ekey, .version = pReader->verRange.maxVer};
+    startKey = (TSDBKEY){.ts = pBlockScanInfo->lastKey - 1, .version = pReader->verRange.maxVer};
   }
 
   int32_t backward = (!ASCENDING_TRAVERSE(pReader->order));
@@ -2669,7 +2689,13 @@ static int32_t buildBlockFromBufferSequentially(STsdbReader* pReader) {
 
 // set the correct start position in case of the first/last file block, according to the query time window
 static void initBlockDumpInfo(STsdbReader* pReader, SDataBlockIter* pBlockIter) {
-  SDataBlk* pBlock = getCurrentBlock(pBlockIter);
+  SDataBlk*            pBlock = getCurrentBlock(pBlockIter);
+  SFileDataBlockInfo*  pBlockInfo = getCurrentBlockInfo(pBlockIter);
+  STableBlockScanInfo* pScanInfo = taosHashGet(pBlockIter->pTableMap, &pBlockInfo->uid, sizeof(pBlockInfo->uid));
+  if (pScanInfo == NULL) {
+    tsdbError("failed to locate the uid:%" PRIu64 " in query table uid list", pBlockInfo->uid);
+    return;
+  }
 
   SReaderStatus* pStatus = &pReader->status;
 
@@ -2678,6 +2704,7 @@ static void initBlockDumpInfo(STsdbReader* pReader, SDataBlockIter* pBlockIter)
   pDumpInfo->totalRows = pBlock->nRow;
   pDumpInfo->allDumped = false;
   pDumpInfo->rowIndex = ASCENDING_TRAVERSE(pReader->order) ? 0 : pBlock->nRow - 1;
+  pDumpInfo->lastKey = pScanInfo->lastKey;
 }
 
 static int32_t initForFirstBlockInFile(STsdbReader* pReader, SDataBlockIter* pBlockIter) {
@@ -3489,8 +3516,6 @@ static int32_t doOpenReaderImpl(STsdbReader* pReader) {
 }
 
 // ====================================== EXPOSED APIs ======================================
-static int32_t tsdbSetQueryReseek(void* pQHandle);
-
 int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, SArray* pTableList, STsdbReader** ppReader,
                        const char* idstr) {
   STimeWindow window = pCond->twindows;
@@ -3571,50 +3596,7 @@ int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, SArray* pTabl
     goto _err;
   }
 
-  if (numOfTables > 0) {
-    code = tsdbTakeReadSnap(pReader, tsdbSetQueryReseek, &pReader->pReadSnap);
-    if (code != TSDB_CODE_SUCCESS) {
-      goto _err;
-    }
-
-    if (pReader->type == TIMEWINDOW_RANGE_CONTAINED) {
-      code = doOpenReaderImpl(pReader);
-      if (code != TSDB_CODE_SUCCESS) {
-        return code;
-      }
-    } else {
-      STsdbReader* pPrevReader = pReader->innerReader[0];
-      STsdbReader* pNextReader = pReader->innerReader[1];
-
-      // we need only one row
-      pPrevReader->capacity = 1;
-      pPrevReader->status.pTableMap = pReader->status.pTableMap;
-      pPrevReader->pSchema = pReader->pSchema;
-      pPrevReader->pMemSchema = pReader->pMemSchema;
-      pPrevReader->pReadSnap = pReader->pReadSnap;
-
-      pNextReader->capacity = 1;
-      pNextReader->status.pTableMap = pReader->status.pTableMap;
-      pNextReader->pSchema = pReader->pSchema;
-      pNextReader->pMemSchema = pReader->pMemSchema;
-      pNextReader->pReadSnap = pReader->pReadSnap;
-
-      code = doOpenReaderImpl(pPrevReader);
-      if (code != TSDB_CODE_SUCCESS) {
-        return code;
-      }
-
-      code = doOpenReaderImpl(pNextReader);
-      if (code != TSDB_CODE_SUCCESS) {
-        return code;
-      }
-
-      code = doOpenReaderImpl(pReader);
-      if (code != TSDB_CODE_SUCCESS) {
-        return code;
-      }
-    }
-  }
+  pReader->suspended = true;
 
   tsdbDebug("%p total numOfTable:%d in this query %s", pReader, numOfTables, pReader->idStr);
   return code;
@@ -3677,6 +3659,8 @@ void tsdbReaderClose(STsdbReader* pReader) {
 
   tsdbUntakeReadSnap(pReader, pReader->pReadSnap);
 
+  taosThreadMutexDestroy(&pReader->readerMutex);
+
   taosMemoryFree(pReader->status.uidCheckInfo.tableUidList);
   SIOCostSummary* pCost = &pReader->cost;
 
@@ -3706,9 +3690,165 @@ void tsdbReaderClose(STsdbReader* pReader) {
   if (pReader->pMemSchema != pReader->pSchema) {
     taosMemoryFree(pReader->pMemSchema);
   }
+
   taosMemoryFreeClear(pReader);
 }
 
+int32_t tsdbReaderSuspend(STsdbReader* pReader) {
+  int32_t code = 0;
+
+  // save reader's base state & reset top state to be reconstructed from base state
+  SReaderStatus*       pStatus = &pReader->status;
+  STableBlockScanInfo* pBlockScanInfo = NULL;
+
+  if (pStatus->loadFromFile) {
+    SFileDataBlockInfo* pBlockInfo = getCurrentBlockInfo(&pReader->status.blockIter);
+    if (pBlockInfo != NULL) {
+      pBlockScanInfo = taosHashGet(pStatus->pTableMap, &pBlockInfo->uid, sizeof(pBlockInfo->uid));
+      if (pBlockScanInfo == NULL) {
+        code = TSDB_CODE_INVALID_PARA;
+        tsdbError("failed to locate the uid:%" PRIu64 " in query table uid list, total tables:%d, %s", pBlockInfo->uid,
+                  taosHashGetSize(pReader->status.pTableMap), pReader->idStr);
+        goto _err;
+      }
+    } else {
+      pBlockScanInfo = pStatus->pTableIter;
+    }
+
+    tsdbDataFReaderClose(&pReader->pFileReader);
+
+    // resetDataBlockScanInfo excluding lastKey
+    STableBlockScanInfo* p = NULL;
+
+    while ((p = taosHashIterate(pStatus->pTableMap, p)) != NULL) {
+      p->iterInit = false;
+      p->iiter.hasVal = false;
+      if (p->iter.iter != NULL) {
+        p->iter.iter = tsdbTbDataIterDestroy(p->iter.iter);
+      }
+
+      p->delSkyline = taosArrayDestroy(p->delSkyline);
+      // p->lastKey = ts;
+    }
+  } else {
+    pBlockScanInfo = pStatus->pTableIter;
+    if (pBlockScanInfo) {
+      // save lastKey to restore memory iterator
+      STimeWindow w = pReader->pResBlock->info.window;
+      pBlockScanInfo->lastKey = ASCENDING_TRAVERSE(pReader->order) ? w.ekey : w.skey;
+
+      // reset current current table's data block scan info,
+      pBlockScanInfo->iterInit = false;
+      // pBlockScanInfo->iiter.hasVal = false;
+      if (pBlockScanInfo->iter.iter != NULL) {
+        pBlockScanInfo->iter.iter = tsdbTbDataIterDestroy(pBlockScanInfo->iter.iter);
+      }
+
+      if (pBlockScanInfo->iiter.iter != NULL) {
+        pBlockScanInfo->iiter.iter = tsdbTbDataIterDestroy(pBlockScanInfo->iiter.iter);
+      }
+
+      pBlockScanInfo->pBlockList = taosArrayDestroy(pBlockScanInfo->pBlockList);
+      tMapDataClear(&pBlockScanInfo->mapData);
+      // TODO: keep skyline for reuse
+      pBlockScanInfo->delSkyline = taosArrayDestroy(pBlockScanInfo->delSkyline);
+    }
+  }
+
+  tsdbUntakeReadSnap(pReader, pReader->pReadSnap);
+
+  pReader->suspended = true;
+
+  tsdbDebug("reader: %p suspended uid %" PRIu64 " in this query %s", pReader, pBlockScanInfo->uid, pReader->idStr);
+  return code;
+
+_err:
+  tsdbError("failed to suspend data reader, code:%s %s", tstrerror(code), pReader->idStr);
+  return code;
+}
+
+static int32_t tsdbSetQueryReseek(void* pQHandle) {
+  int32_t      code = 0;
+  STsdbReader* pReader = pQHandle;
+
+  taosThreadMutexLock(&pReader->readerMutex);
+
+  if (pReader->suspended) {
+    taosThreadMutexUnlock(&pReader->readerMutex);
+    return code;
+  }
+
+  tsdbReaderSuspend(pReader);
+
+  taosThreadMutexUnlock(&pReader->readerMutex);
+
+  return code;
+}
+
+int32_t tsdbReaderResume(STsdbReader* pReader) {
+  int32_t code = 0;
+
+  STableBlockScanInfo* pBlockScanInfo = pReader->status.pTableIter;
+
+  //  restore reader's state
+  //  task snapshot
+  size_t numOfTables = taosHashGetSize(pReader->status.pTableMap);
+  if (numOfTables > 0) {
+    code = tsdbTakeReadSnap(pReader, tsdbSetQueryReseek, &pReader->pReadSnap);
+    if (code != TSDB_CODE_SUCCESS) {
+      goto _err;
+    }
+
+    if (pReader->type == TIMEWINDOW_RANGE_CONTAINED) {
+      code = doOpenReaderImpl(pReader);
+      if (code != TSDB_CODE_SUCCESS) {
+        return code;
+      }
+    } else {
+      STsdbReader* pPrevReader = pReader->innerReader[0];
+      STsdbReader* pNextReader = pReader->innerReader[1];
+
+      // we need only one row
+      pPrevReader->capacity = 1;
+      pPrevReader->status.pTableMap = pReader->status.pTableMap;
+      pPrevReader->pSchema = pReader->pSchema;
+      pPrevReader->pMemSchema = pReader->pMemSchema;
+      pPrevReader->pReadSnap = pReader->pReadSnap;
+
+      pNextReader->capacity = 1;
+      pNextReader->status.pTableMap = pReader->status.pTableMap;
+      pNextReader->pSchema = pReader->pSchema;
+      pNextReader->pMemSchema = pReader->pMemSchema;
+      pNextReader->pReadSnap = pReader->pReadSnap;
+
+      code = doOpenReaderImpl(pPrevReader);
+      if (code != TSDB_CODE_SUCCESS) {
+        return code;
+      }
+
+      code = doOpenReaderImpl(pNextReader);
+      if (code != TSDB_CODE_SUCCESS) {
+        return code;
+      }
+
+      code = doOpenReaderImpl(pReader);
+      if (code != TSDB_CODE_SUCCESS) {
+        return code;
+      }
+    }
+  }
+
+  pReader->suspended = false;
+
+  tsdbDebug("reader: %p resumed uid %" PRIu64 ", numOfTable:%" PRIu64 ", in this query %s", pReader,
+            pBlockScanInfo ? pBlockScanInfo->uid : 0, numOfTables, pReader->idStr);
+  return code;
+
+_err:
+  tsdbError("failed to resume data reader, code:%s %s", tstrerror(code), pReader->idStr);
+  return code;
+}
+
 static bool doTsdbNextDataBlock(STsdbReader* pReader) {
   // cleanup the data that belongs to the previous data block
   SSDataBlock* pBlock = pReader->pResBlock;
@@ -3741,12 +3881,23 @@ bool tsdbNextDataBlock(STsdbReader* pReader) {
     return false;
   }
 
+  SReaderStatus* pStatus = &pReader->status;
+
+  taosThreadMutexLock(&pReader->readerMutex);
+  if (pReader->suspended) {
+    tsdbReaderResume(pReader);
+  }
+
   if (pReader->innerReader[0] != NULL && pReader->step == 0) {
     bool ret = doTsdbNextDataBlock(pReader->innerReader[0]);
     resetDataBlockScanInfo(pReader->innerReader[0]->status.pTableMap, pReader->innerReader[0]->window.ekey);
     pReader->step = EXTERNAL_ROWS_PREV;
 
     if (ret) {
+      if (pStatus->composedDataBlock) {
+        taosThreadMutexUnlock(&pReader->readerMutex);
+      }
+
       return ret;
     }
   }
@@ -3757,6 +3908,10 @@ bool tsdbNextDataBlock(STsdbReader* pReader) {
 
   bool ret = doTsdbNextDataBlock(pReader);
   if (ret) {
+    if (pStatus->composedDataBlock) {
+      taosThreadMutexUnlock(&pReader->readerMutex);
+    }
+
     return ret;
   }
 
@@ -3765,10 +3920,18 @@ bool tsdbNextDataBlock(STsdbReader* pReader) {
     bool ret1 = doTsdbNextDataBlock(pReader->innerReader[1]);
     pReader->step = EXTERNAL_ROWS_NEXT;
     if (ret1) {
+      if (pStatus->composedDataBlock) {
+        taosThreadMutexUnlock(&pReader->readerMutex);
+      }
+
       return ret1;
     }
   }
 
+  if (pStatus->composedDataBlock) {
+    taosThreadMutexUnlock(&pReader->readerMutex);
+  }
+
   return false;
 }
 
@@ -3903,6 +4066,8 @@ static SArray* doRetrieveDataBlock(STsdbReader* pReader) {
     return NULL;
   }
 
+  taosThreadMutexUnlock(&pReader->readerMutex);
+
   copyBlockDataToSDataBlock(pReader, pBlockScanInfo);
   return pReader->pResBlock->pDataBlock;
 }
@@ -4174,20 +4339,3 @@ void tsdbUntakeReadSnap(STsdbReader* pReader, STsdbReadSnap* pSnap) {
   }
   tsdbTrace("vgId:%d, untake read snapshot", TD_VID(pTsdb->pVnode));
 }
-
-static int32_t tsdbSetQueryReseek(void* pQHandle) {
-  int32_t code = 0;
-
-  // lock handle
-
-  // check state (is already in reseek state, skip below)
-
-  // save all state for further restore
-
-  // unref read snapshot
-  // tsdbUntakeReadSnap();
-
-  // unlock handle
-
-  return code;
-}