There was one MySQL feature that I was always very afraid to ask for. I sure needed it for past 15 years of my MySQL practice, and yet I never got to it. I wanted MySQL processlist (‘SHOW PROCESSLIST’, later – information_schema.processlist) to have more accurate query execution time.
I submitted a patch for that to MongoDB (and it got merged and released really quickly). I couldn’t admit to myself and others that MySQL does not have this functionality, even though it is hard to reason about systems in production without such data.
When 99.999% of queries happen within 1s, …[Read more...]