I have an application which needs a database + would greatly benefit from a [MVCC](http://en.wikipedia.org/wiki/Multiversion_concurrency_control) model. It would ideally support permanent history storage, access of the data at a particular point in time, and incremental backups. 

I'm looking at the databases that might support this. I know CouchDB can (aside from the incremental backups, I'm not sure about that) but in this application I really need a relational database.

I'm surprised that [MySQL lists MVCC support](http://dev.mysql.com/doc/refman/5.1/en/innodb-multi-versioning.html) in Innodb / Falcon. I get the impression that maybe this is only for the database state within a transaction, and once all the transaction levels are committed, the history is lost.

What about [PostgreSQL](http://www.postgresql.org/)?