We ran Presto directly on Github (I think it still does), so everything went directly to the project without a private internal review first. We designed it this way, so that everyone in the community could participate in the full process.
The implication is that a bachelor's degree is costing more and generates less income, but what the graph shows is "total student loan debt" not the "cost of a bachelor's degree".
Technically this graph could be a good thing if we could graduating significantly more people who make more than someone without a degree (but 10% less someone who earned a degree 5 years ago), since more people would be better off.
Other things to note:
The time period is arbitrary and mostly shows the impact of the recession over the past 5 years.
The graph shows total student load debt which includes everything from vocational programs to PHD students in public and private institutions.
The graph has two independent scales so the slopes are arbitrary.
Sorry, didn't answer the core question. We are working on a Scuba connector specifically to bring joins and other powerful SQL features to Scuba. These features are handled by the Presto query engine, so data in existing non-relation systems can be easily analyzed. Even better, Presto can join data across connectors to formerly isolated systems.
Connecting Presto to a relational database is a tricky question. If you just want to have Presto scan the table and perform all computation in Presto, it is pretty easy, but for this to perform well, you would want to push down some of the computation to the database. The other problem is if you only have one database, you would have hundreds of cores hammering that single database for data.
That said, earlier this year, during a hackathon, we build a prototype connector that could split a query and push down the relevant parts to a distributed database that supports simple aggregations. It would be more work to clean this up and integrate, so if a lot of people are interested in this we can prioritize that.