[bedman12345]

Most database companies run only a small amount of tests before committing. After committing, you run tests for thousands of hours. It sucks. You probably do this all day every day. You just run the tests on whatever you have currently committed. you kind of have to be careful about not adding more tests that make it take much much longer. See https://news.ycombinator.com/item?id=18442941

[brazzy]

Ahh, thanks, that piece of information suddenly makes TFA makes sense. I was wondering how it could be that those issues were not caught by unit tests before committing/merging, but seemed to be caught soon afterwards in a way that they could still immediately be ascribed to a specific commit.