I have many to many relational data model. For example , i have a chat room and it has many users. {Chatroom: ChatRoomID:ID, Somedata... User:{ ID:userid, Somedata... } } I have a user object and i need to filtre those by user.

DataStore.query(ChatRoom,e=>e.User.Id("eq",myID))

I tried to query the data which has my userid then get the ChatRoomID. But i didnt work as expected. I can filter it with its main keys but i cant go through inside the object to filter. Currently i am doing this the same as the aws document. Which is-->

DataStore.query(ChatRoom).filter(e=> e.user.id==myID)

My concern is ,is this query above gets the whole data to filter ? For the first one, it looks like it getting the filtered data like select queries as we do in SQL. But i m worried about using second one. What if i have 100.000 rooms and 500.000 users inside it ? Is it get the whole data before filtering with a JavaScript functions like filter, map etc. ? I dont get the logic behind.