fix:add log

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

@@ -148,7 +148,6 @@ static int32_t mndPersistSubChangeVgReq(SMnode *pMnode, STrans *pTrans, const SM
   SVgObj *pVgObj = mndAcquireVgroup(pMnode, vgId);
   if (pVgObj == NULL) {
     taosMemoryFree(buf);
-    terrno = TSDB_CODE_OUT_OF_MEMORY;
     return -1;
   }
 
@@ -670,7 +669,7 @@ static int32_t mndProcessRebalanceReq(SRpcMsg *pMsg) {
     // possibly no vg is changed
     // when each topic is re-balanced, issue an trans to save the results in sdb.
     if (mndPersistRebResult(pMnode, pMsg, &rebOutput) < 0) {
-      mError("mq re-balance persist output error, possibly vnode splitted or dropped");
+      mError("mq re-balance persist output error, possibly vnode splitted or dropped,msg:%s", terrstr());
     }
 
     taosArrayDestroy(rebOutput.newConsumers);