[TD-147] fix invalid write in drop vgroup

src/mnode/src/mgmtDb.c

@@ -351,8 +351,27 @@ bool mgmtCheckIsMonitorDB(char *db, char *monitordb) {
   return (strncasecmp(dbName, monitordb, len) == 0 && len == strlen(monitordb));
 }
 
+#if 0
+void mgmtPrintVgroups(SDbObj *pDb, char *oper) {
+  mPrint("db:%s, vgroup link from head, oper:%s", pDb->name, oper);  
+  SVgObj *pVgroup = pDb->pHead;
+  while (pVgroup != NULL) {
+    mPrint("vgId:%d", pVgroup->vgId);
+    pVgroup = pVgroup->next;
+  }
+
+  mPrint("db:%s, vgroup link from tail", pDb->name, pDb->numOfVgroups);
+  pVgroup = pDb->pTail;
+  while (pVgroup != NULL) {
+    mPrint("vgId:%d", pVgroup->vgId);
+    pVgroup = pVgroup->prev;
+  }
+}
+#endif
+
 void mgmtAddVgroupIntoDb(SVgObj *pVgroup) {
   SDbObj *pDb = pVgroup->pDb;
+
   pVgroup->next = pDb->pHead;
   pVgroup->prev = NULL;
 

src/mnode/src/mgmtVgroup.c

@@ -516,7 +516,7 @@ void mgmtAddTableIntoVgroup(SVgObj *pVgroup, SChildTableObj *pTable) {
   }
   
   if (pVgroup->numOfTables >= pVgroup->pDb->cfg.maxTables) {
-    mgmtAddVgroupIntoDbTail(pVgroup);
+    mgmtMoveVgroupToTail(pVgroup);
   }
 
   mgmtIncVgroupRef(pVgroup);
@@ -529,10 +529,7 @@ void mgmtRemoveTableFromVgroup(SVgObj *pVgroup, SChildTableObj *pTable) {
     pVgroup->numOfTables--;
   }
 
-  if (pVgroup->numOfTables == 0) {
-    mgmtRemoveVgroupFromDb(pVgroup);
-  }
-
+  mgmtMoveVgroupToHead(pVgroup);
   mgmtDecVgroupRef(pVgroup);
 }