- Raw source
- Hand-built queries
- Reports that disagree
- Raw source
- Dimensional model
- Tested metric layer
- Reports that agree
A fleet operator's reports disagreed with each other, because each one was built from an unmodelled source by hand.
What we built
Oceanic Atlas: a dimensional model derived from that source, and a metric layer regression-tested against production data. Delivered by a single engineer.
What changed
One set of numbers. Every report agrees, and the tests prove it.