So we are writing an app whose schema should reference data which lies currently in an external PostgreSQL instance. We are negotiating being able to put our schema within the external database, but we are evaluating different possibilities.
One option I'm pondering is basing our app on PostgreSQL and use its facilities for accessing external PostgreSQL instances.
What's the status of this?
PG's documentation contains http://www.postgresql.org/docs/9.1/static/sql-createserver.html and http://www.postgresql.org/docs/9.1/static/sql-createforeigntable.html , which allow you to reference tables in an external server. What's their status? Are queries performant (i.e. sends WHERE to the other side)? Can you reasonably join between local and foreign tables?
There's also pgsql_fdw ( http://interdbconnect.sourceforge.net/pgsql_fdw/pgsql_fdw-en.html ), which seems more featureful. Does it offer an improvement on the above? Anyone using it?