Today I was trying to find out if Redgate supports PostgreSQL. It does not, but there is an alternative to Redgate that can be used to compare PostgreSQL databases. This alternative is not a software solution, rather it’s something you can do with PostgreSQL. Here’s what I found:
use pg_dump -s and then diff the results. This gives you a textual dump of the database, and for identical databases, it should work, provided the same version of pg_dump is used. You may have to grep out the comments depending on the version of pg_dump used.
The one huge caveat here is that this dumps columns in their physical order, so you would have to make sure that all DDL scripts are run in the same order on both.