Was working for MarkLogic and got pulled into this a couple days before launch. That sort of thing was the least of their worries. They got the model wrong.

Was working for MarkLogic and got pulled into this a couple days before launch. That sort of thing was the least of their worries. They got the model wrong. With ACA, you were not allowed to do policy pricing on preexisting conditions. Age, sex, smoking, and location. That really only leaves one variable - location - for the actuarial folks to create unique policies. You might suspect how this breaks things. A healthy 18yo female in Tampa could have hundreds of thousands of policies. Live on a superfund site... hey, about those 3 spendy options. Those files could be massive - hundreds of MB. The log files... ye gods... those things grew in GB fast. 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.