Firebase Database Listener performance on Android -

i trying make chat application based on suggestions in firebase documentation denormalizing.

i have list of chat rooms user part of in user node this:

{   "user": {     "chat_ids": {       "room_1_id": true,       "room_2_id": true     }   } } 

and chat node as:

{   "room_1_id": {     "last_posted": "date"   },   "room_2_id": {     "last_posted": "date"   } } 

the chat node has rules prevent members aren't part of room read node. getting list of chat ids user node , getting details of each chat , attaching listeners each chat child detect change in them.

my question in case user part of 20+ chat rooms, there 20 listeners, cause performance issues? if there alternate way solve issue?