In Rails 4, User.count and User.all.count both do the same thing:

  SELECT COUNT(*) FROM "users"

In earlier versions, User.all.count executes:

  SELECT "users".* FROM "users"

because it is pulling back all fields from all users into memory, instead of just asking the database to check the index for a count.

You should use "User.count", which will do something like "select count(*) from users".

"Users.all.count" will needlessly read in all users into memory and then return a count. That might work OK for 1000 users, but beyond that?

Newb question here - Did you use Rails as your backend? How does it fit into your stack as an iOS app? Are you using something like RubyMotion? Just curious...

User.count would do it.