The problem here is "unknown unknowns," coupled with the real business pressure to get solutions out the door. The MySQL manual is (currently) over 6,000 pages.

The problem here is "unknown unknowns," coupled with the real business pressure to get solutions out the door. The MySQL manual is (currently) over 6,000 pages. A developer new to SQL or relational DBs doesn't know how many of those are necessary to read and comprehend to deploy a working solution. And in this case, she designed and deployed the system, and it worked and met the business needs for several months. When performance became an issue, she optimized. I'm sure she had plenty of other unrelated work to do in the meantime, especially as a lead/solo dev in the early 2000's. Sounds like a productive developer to me.