How to find out the connection limit per user on Postgresql?
This information is available in the column rolconnlimit in the view pg_roles
http://www.postgresql.org/docs/current/static/view-pg-roles.html
For roles that can log in, this sets maximum number of concurrent connections this role can make. -1 means no limit.
Whilst connected to the database you want to get this information
SELECT rolname, rolconnlimit
FROM pg_roles
WHERE rolconnlimit <> -1;
More details are available at http://www.postgresql.org/docs/current/static/view-pg-roles.html