Three hours? My own time was about 45 minutes (at MemSQL, did not get an offer), completely unprepared. It's not a complicated codebase to comprehend, and you c

Three hours? My own time was about 45 minutes (at MemSQL, did not get an offer), completely unprepared. It's not a complicated codebase to comprehend, and you can rely on the existing plumbing for other ops. The best candidate I've interviewed also implemented DTrace instrumentation support for this in the same amount of time. I do agree this is a great question, far better than irrelevant Leetcode bullshit that gets typically asked. At least it's far more predictive of the actual on-the-job performance, because this is what the candidate will be doing mostly, as their job.