Do they still limit the usage of user defined functions and contrib modules, or did that open up? I would love to use Heroku for some lightweight data warehousing that I've got going, but it's still pretty dependent on functions/sprocs for performance reasons.
I looked for any more documentation about that, but the only official word I have from them in the past is the support ticket I filed last year stating that they don't support "additions" like user defined functions or the various contrib modules.
Our production service has always supported UDFs, though the free sandbox service does not.
Unfortunately, Postgres makes it difficult to install extension modules without superuser. That said, we've wanted to support contrib modules for ages. Lately, encouraged by the work Dimitri Fontaine has been doing on extensions, we have a pilot project going which includes support for hstore, pgcrypto, pg_trgm, and of course, postgis. Feel free to contact me at pvh(at)heroku.com if you're interested in taking it for a spin.
We're running user-defined functions on Heroku right now (using a functional index on a custom hash function to get fast space-efficient queries on a string column of a large table).
I looked for any more documentation about that, but the only official word I have from them in the past is the support ticket I filed last year stating that they don't support "additions" like user defined functions or the various contrib modules.