We're running PostgreSQL as essentially a data warehouse, and we have a few thousand roles, which are used to grant permissions on a table-by-table basis to a few thousand users, so a user would typically have say between 1 and 2 thousand roles. There is also quite a lot of "churn" in terms of tables being created/removed, and permissions changed.
The issue is that we're hitting a strange performance problem on connection. Sometimes it can take ~25 to 40 seconds just to connect, although it's often way quicker
