[TD-2752]<fix>: check if the FILE pointer is valid or not.

src/query/src/qExecutor.c

@@ -6928,11 +6928,12 @@ static size_t getResultSize(SQInfo *pQInfo, int64_t *numOfRows) {
    */
   if (isTSCompQuery(pQuery) && (*numOfRows) > 0) {
     struct stat fStat;
-    if (fstat(fileno(*(FILE **)pQuery->sdata[0]->data), &fStat) == 0) {
+    FILE *f = *(FILE **)pQuery->sdata[0]->data;
+    if ((f != NULL) && (fstat(fileno(f), &fStat) == 0)) {
       *numOfRows = fStat.st_size;
       return fStat.st_size;
     } else {
-      qError("QInfo:%p failed to get file info, path:%s, reason:%s", pQInfo, pQuery->sdata[0]->data, strerror(errno));
+      qError("QInfo:%p failed to get file info, file:%p, reason:%s", pQInfo, f, strerror(errno));
       return 0;
     }
   } else {
@@ -6947,7 +6948,7 @@ static int32_t doDumpQueryResult(SQInfo *pQInfo, char *data) {
   // load data from file to msg buffer
   if (isTSCompQuery(pQuery)) {
 
-    FILE *f = *(FILE **)pQuery->sdata[0]->data;
+    FILE *f = *(FILE **)pQuery->sdata[0]->data;  // TODO refactor
 
     // make sure file exist
     if (f) {