[td-225] update the error code when system related error happens.

src/query/inc/qextbuffer.h

@@ -149,7 +149,7 @@ int16_t tExtMemBufferPut(tExtMemBuffer *pMemBuffer, void *data, int32_t numOfRow
  * @param pMemBuffer
  * @return
  */
-bool tExtMemBufferFlush(tExtMemBuffer *pMemBuffer);
+int32_t tExtMemBufferFlush(tExtMemBuffer *pMemBuffer);
 
 /**
  *

src/query/src/qextbuffer.c

@@ -245,30 +245,29 @@ static void tExtMemBufferClearFlushoutInfo(tExtMemBuffer *pMemBuffer) {
   memset(pFileMeta->flushoutData.pFlushoutInfo, 0, sizeof(tFlushoutInfo) * pFileMeta->flushoutData.nAllocSize);
 }
 
-bool tExtMemBufferFlush(tExtMemBuffer *pMemBuffer) {
+int32_t tExtMemBufferFlush(tExtMemBuffer *pMemBuffer) {
+  int32_t ret = 0;
   if (pMemBuffer->numOfTotalElems == 0) {
-    return true;
+    return ret;
   }
 
   if (pMemBuffer->file == NULL) {
     if ((pMemBuffer->file = fopen(pMemBuffer->path, "wb+")) == NULL) {
-      return false;
+      ret = TAOS_SYSTEM_ERROR(errno);
+      return ret;
     }
   }
 
   /* all data has been flushed to disk, ignore flush operation */
   if (pMemBuffer->numOfElemsInBuffer == 0) {
-    return true;
+    return ret;
   }
 
-  bool ret = true;
-  
   tFilePagesItem *first = pMemBuffer->pHead;
-
   while (first != NULL) {
     size_t retVal = fwrite((char *)&(first->item), pMemBuffer->pageSize, 1, pMemBuffer->file);
     if (retVal <= 0) {  // failed to write to buffer, may be not enough space
-      ret = false;
+      ret = TAOS_SYSTEM_ERROR(errno);
     }
 
     pMemBuffer->fileMeta.numOfElemsInFile += first->item.num;