Lessons we learned when debugging a scaling problem
> <i>Lesson #4: When you choose specific non-default settings, leave a comment or link to documentation/issues as to why, future people will thank you.</i><p>Put it <i>in the commit message</i>. There is no better place to put it. That is the exact point in time at which you have the most information about that exact change. Commit messages are cheap, be liberal with your words and links.<p>It drives me nuts to read commit messages of the form "fix", "fixed 2", "add test", "new var" and on and on. You took an hour to make the change, take a damn minute to save some future colleague a day of frustration.