I want to keep a list of UserIDs who are now online.
I can keep a string as a doc and append to it (using Append) whenever a new user logs in. That’s easy and fast.
But how can I remove from it as easily and fast ?
I can also read the appended string, remove the value from it and save it again on log out but I’m looking for an only write (not read, modify, write) way.
I can also create a doc with key UserID::login when a user logs in and remove that key when a user logs out. But I cannot compose a list of who is connected.
What if the list is very long, ~100,000s ?
What is the preferred way ? Is there a better way here ?