You think so? Maybe but the ORM lines should be pretty insulated. If you return the same results and only speed them up you should be okay. To take an example

You think so? Maybe but the ORM lines should be pretty insulated. If you return the same results and only speed them up you should be okay. To take an example, replacing any? with exists? doesn't seem to require testing everywhere in the project. I imagine that the average fix had lines like that. I also suspect that the fixes were pareto distributed -- that a few fixes brought most of the benefit.