If you'd like to improve MediaWiki's support for PostgreSQL, consider submitting a talk about it to PG Day:

http://pgday.consistentstate.com/node/5

PG-Day Denver 2011 will be held on Friday, October 21st, 2011 at the Auraria Campus near downtown Denver, Colorado, USA. PG-Day Denver will include talks that will benefit PostgreSQL users, database administrators, developers, and executives. The call for papers is open till August 31, but it's better to submit earlier.