[TD-492]

src/system/detail/src/vnodeQueryImpl.c

@@ -2802,6 +2802,7 @@ static int32_t rowwiseApplyAllFunctions(SQueryRuntimeEnv *pRuntimeEnv, int32_t *
     }
   }
  
+  if (lastIndex >= 0) { 
     // save the last accessed row of current data block for interpolation
     int32_t index = GET_COL_DATA_POS(pQuery, lastIndex, step);
     for(int32_t i = 0; i < pQuery->numOfCols; ++i) {
@@ -2810,6 +2811,7 @@ static int32_t rowwiseApplyAllFunctions(SQueryRuntimeEnv *pRuntimeEnv, int32_t *
     
       memcpy(pRuntimeEnv->lastRowInBlock[i], pRuntimeEnv->colDataBuffer[i]->data + s, pColInfo->bytes);
     }
+  }
 
   free(sasArray);