enh(sync): syncStartStandBy

source/dnode/mnode/impl/inc/mndInt.h

@@ -81,6 +81,7 @@ typedef struct {
   sem_t      syncSem;
   int64_t    sync;
   ESyncState state;
+  bool       isStandBy;
 } SSyncMgmt;
 
 typedef struct {

source/dnode/mnode/impl/src/mndSync.c

@@ -182,7 +182,11 @@ int32_t mndSyncPropose(SMnode *pMnode, SSdbRaw *pRaw) {
 void mndSyncStart(SMnode *pMnode) {
   SSyncMgmt *pMgmt = &pMnode->syncMgmt;
   syncSetMsgCb(pMgmt->sync, &pMnode->msgCb);
-  syncStart(pMgmt->sync);
+  if (pMgmt->isStandBy) {
+    syncStartStandBy(pMgmt->sync);
+  } else {
+    syncStart(pMgmt->sync);
+  }
   mDebug("sync:%" PRId64 " is started", pMgmt->sync);
 }