When are ENUMS joined in in PostgreSQL
If I run a select from a column in PostgreSQL that is of type enum, are the string values of the enum joined in before or after the final result set has been created? An explanation of my motive can be found at http://archives.postgresql.org/pgsql-performance/2008-07/msg00226.php
Internally it uses the OID the whole time. But you can cast that to text at any time.