This is only tangentially related... are there any open source databases that implement materialized views as well as Oracle? Postgres is getting close but they're not there yet...
Sure, what I think Oracle does better is it provides a lot more flexibility with how you can refresh your materialized views. Oracle has 3 ways that I know of to refresh materialized views; complete, fast, and partition change tracking, furthermore Oracle allows you to refresh on commit instead of have to manually do it or schedule a job to do it.
Although it has nothing to do with materialized views Oracle also has a built in scheduler, which can be used to do periodic refreshes (hourly, nightly, etc). You can achieve something similar with postgres by croning a SQL script.
To my knowledge postgres doesn't really have these things (other than in 9.5? you can do refreshes without getting an exclusive lock like in 9.4), although I could be wrong. I just wish Oracle wasn't so expensive.
I don't disagree that oracle has excellent materialized view support, but triggers and other strategies can go a long way also, I think Dan Chak did a really nice chapter on this in his book enterprise rails, that is also available online for free at http://dan.chak.org/enterprise-rails/chapter-12-materialized...
