I can certainly vouch for the first four of these (though I did 4 before 3) when I had to debug something that only seemed to show itself on large datasets. It was a homegrown (not by me) sort problem associated with report display which apparently had been there for years and not even noticed given the volume of data required for it to appear.

My approach was to do the first two steps, but then ask myself “How could this go wrong,” which was my hypothesis step. That led me to the bug and figuring out how to demonstrate it and the fix with a dramatically smaller amount of data. And, like many problem-solving situations I’m sure people experience, after some time studying the problem, I came upon the solution after going to sleep one night and waking up with a eureka moment.