enh(query): improve the perf.

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

@@ -985,6 +985,8 @@ static int32_t copyBlockDataToSDataBlock(STsdbReader* pReader, STableBlockScanIn
           uint8_t* p = pData->pData + tDataTypes[pData->type].bytes * pDumpInfo->rowIndex;
           memcpy(pColData->pData, p, remain * tDataTypes[pData->type].bytes);
 
+          ASSERT((((uint64_t)pColData->pData) & (0x8 - 1)) == 0); // make sure it is aligned to 8bit
+
           // null value exists, check one-by-one
           if (pData->flag != HAS_VALUE) {
             for (int32_t j = pDumpInfo->rowIndex; rowIndex < remain; j += step, rowIndex++) {

source/libs/function/src/builtinsimpl.c

@@ -906,6 +906,7 @@ int32_t avgFunction(SqlFunctionCtx* pCtx) {
 
       case TSDB_DATA_TYPE_FLOAT: {
         float* plist = (float*)pCol->pData;
+        float val = 0;
         for (int32_t i = start; i < numOfRows + pInput->startRowIndex; ++i) {
           if (pCol->hasNull && colDataIsNull_f(pCol->nullbitmap, i)) {
             continue;
@@ -913,8 +914,9 @@ int32_t avgFunction(SqlFunctionCtx* pCtx) {
 
           numOfElem += 1;
           pAvgRes->count += 1;
-          pAvgRes->sum.dsum += plist[i];
+          val += plist[i];
         }
+        pAvgRes->sum.dsum = val;
         break;
       }