nope it was exactly that; transactional customer state in giant xml documents in an xml-document-storing database. Bugs would cause them to grow to 10, 20, 100MB.
The other gotcha was Java is single inheritance. Foo > XML. Bar extends Foo > XML. Baz extends Foo > /dev/null the Bar bits in the persistence layer.
The MarkLogic bits did OK. When everything went sideways at launch, almost no traffic was getting all the way to the back end. Because things were getting profiled, there was way more time to tune and tweak the indexes as they tried to re-engineer things. The NoSQL bits helped there, as it made it a bit easier to morph things as it was refactored.
Not to say there were not pain points or they did not have a silly amount of hardware in it in the end.
One of the more memorable things for me was working in the XOC, having an update go sideways in the early AM, and seeing CNN pop up a ticker saying ACA was down. Good times.
[0] https://lobste.rs/s/igt4ez/10_year_anniversary_healthcare_go...
[1] https://en.wikipedia.org/wiki/MarkLogic
[2] https://lobste.rs/s/igt4ez/10_year_anniversary_healthcare_go...