In Datomic, how do you efficiently perform queries such as 'find all people living in Washington older than 50' (city and age may vary)? In relational databases and most of NoSQL databases you use composite indexes for this purpose; Datomic, as far as I'm aware of, does not support anything like this.
I built several, say, medium-sized web-apps and not a single one would perform quick enough, if not for composite indexes. How are Datomic users dealing with this? Or are they just playing with datasets small enough not to suffer from this? Am I missing something?
Update 2019-06-28: Since 0.9.5927 (Datomic On-Prem) / 480-8770 (Datomic Cloud), Datomic supports Tuples as a new Attribute Type, which allows you to have compound indexes.