The complaint usually arrives in the same shape. The product was fine. Nobody changed the architecture. And now a list screen takes nine seconds, the mobile app times out on export, and it is getting worse every month — for everyone, not for one customer on one screen.

Nothing broke. That is the part worth sitting with, because it decides where you look.

00 / Growth does not break a data model. It reveals one.

A data model encodes the assumptions of the weeks it was written in: how many records there would be, how many tenants, which screens would read what. Those assumptions are rarely written down, and they are never wrong on day one — there is not enough data for them to be wrong yet.

What changes is the volume, and volume turns a constant-time mistake into a linear one. A full table read costs nothing at a thousand items. At a hundred thousand it is the product.

So the question is not "what regressed?" Nothing regressed.…