In one embodiment, a method includes receiving, from a client device of a first user of an online social network, a structured query comprising references to one or more selected objects associated with the online social network, parsing the structured query to identify a first query constraint and one or more second query constraints, identifying an inverse constraint associated with the first query constraint, wherein the first query constraint has been previously flagged as identifying greater than a threshold number of objects, and generating a query command based on the structured query, wherein the query command comprises the inverse constraint and the one or more second query constraints.