[TD-2910]<fix>: fix onlineDnodes > totalDnodes issue

src/mnode/inc/mnodeDnode.h

@@ -67,6 +67,7 @@ void    mnodeCleanupDnodes();
 int32_t mnodeGetDnodesNum();
 int32_t mnodeGetOnlinDnodesCpuCoreNum();
 int32_t mnodeGetOnlineDnodesNum();
+void    mnodeGetOnlineAndTotalDnodesNum(int32_t *onlineNum, int32_t *totalNum);
 void *  mnodeGetNextDnode(void *pIter, SDnodeObj **pDnode);
 void    mnodeCancelGetNextDnode(void *pIter);
 void    mnodeIncDnodeRef(SDnodeObj *pDnode);

src/mnode/src/mnodeDnode.c

@@ -263,6 +263,28 @@ int32_t mnodeGetOnlineDnodesNum() {
   return onlineDnodes;
 }
 
+void mnodeGetOnlineAndTotalDnodesNum(int32_t *onlineNum, int32_t *totalNum) {
+  SDnodeObj *pDnode = NULL;
+  void *     pIter = NULL;
+  int32_t    onlineDnodes = 0, totalDnodes = 0;
+
+  while (1) {
+    pIter = mnodeGetNextDnode(pIter, &pDnode);
+    if (pDnode == NULL) break;
+    if (pDnode->status != TAOS_DN_STATUS_OFFLINE) ++onlineDnodes;
+    ++totalDnodes;
+    mnodeDecDnodeRef(pDnode);
+  }
+
+  if (onlineNum) {
+    *onlineNum = onlineDnodes;
+  }
+
+  if (totalNum) {
+    *totalNum = totalDnodes;
+  }
+}
+
 void *mnodeGetDnode(int32_t dnodeId) {
   return sdbGetRow(tsDnodeSdb, &dnodeId);
 }

src/mnode/src/mnodeShow.c

@@ -280,8 +280,11 @@ static int32_t mnodeProcessHeartBeatMsg(SMnodeMsg *pMsg) {
     }
   }
 
-  pRsp->onlineDnodes = htonl(mnodeGetOnlineDnodesNum());
-  pRsp->totalDnodes = htonl(mnodeGetDnodesNum());
+  int32_t    onlineDnodes = 0, totalDnodes = 0;
+  mnodeGetOnlineAndTotalDnodesNum(&onlineDnodes, &totalDnodes);
+
+  pRsp->onlineDnodes = htonl(onlineDnodes);
+  pRsp->totalDnodes = htonl(totalDnodes);
   mnodeGetMnodeEpSetForShell(&pRsp->epSet, false);
 
   pMsg->rpcRsp.rsp = pRsp;