fix(query): check for null value.

source/dnode/vnode/src/tsdb/tsdbRead.c

@@ -640,12 +640,12 @@ static int32_t doLoadBlockIndex(STsdbReader* pReader, SDataFReader* pFileReader,
     }
 
     // this block belongs to a table that is not queried.
-    void* p = *(STableBlockScanInfo**)taosHashGet(pReader->status.pTableMap, &pBlockIdx->uid, sizeof(uint64_t));
+    void* p = taosHashGet(pReader->status.pTableMap, &pBlockIdx->uid, sizeof(uint64_t));
     if (p == NULL) {
       continue;
     }
 
-    STableBlockScanInfo* pScanInfo = p;
+    STableBlockScanInfo* pScanInfo = *(STableBlockScanInfo**)p;
     if (pScanInfo->pBlockList == NULL) {
       pScanInfo->pBlockList = taosArrayInit(4, sizeof(SBlockIndex));
     }
@@ -689,7 +689,8 @@ static int32_t doLoadFileBlock(STsdbReader* pReader, SArray* pIndexList, SBlockN
   for (int32_t i = 0; i < numOfTables; ++i) {
     SBlockIdx* pBlockIdx = taosArrayGet(pIndexList, i);
 
-    STableBlockScanInfo* pScanInfo = taosHashGet(pReader->status.pTableMap, &pBlockIdx->uid, sizeof(int64_t));
+    STableBlockScanInfo* pScanInfo =
+        *(STableBlockScanInfo**)taosHashGet(pReader->status.pTableMap, &pBlockIdx->uid, sizeof(int64_t));
 
     tMapDataReset(&pScanInfo->mapData);
     tsdbReadDataBlk(pReader->pFileReader, pBlockIdx, &pScanInfo->mapData);
@@ -1137,14 +1138,14 @@ static int32_t fileDataBlockOrderCompar(const void* pLeft, const void* pRight, v
 static int32_t doSetCurrentBlock(SDataBlockIter* pBlockIter, const char* idStr) {
   SFileDataBlockInfo* pBlockInfo = getCurrentBlockInfo(pBlockIter);
   if (pBlockInfo != NULL) {
-    STableBlockScanInfo* pScanInfo = taosHashGet(pBlockIter->pTableMap, &pBlockInfo->uid, sizeof(pBlockInfo->uid));
+    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, %s", pBlockInfo->uid, idStr);
       return TSDB_CODE_INVALID_PARA;
     }
 
-    SBlockIndex* pIndex = taosArrayGet(pScanInfo->pBlockList, pBlockInfo->tbBlockIdx);
-    tMapDataGetItemByIdx(&pScanInfo->mapData, pIndex->ordinalIndex, &pBlockIter->block, tGetDataBlk);
+    SBlockIndex* pIndex = taosArrayGet((*pScanInfo)->pBlockList, pBlockInfo->tbBlockIdx);
+    tMapDataGetItemByIdx(&(*pScanInfo)->mapData, pIndex->ordinalIndex, &pBlockIter->block, tGetDataBlk);
   }
 
 #if 0