Thank you Michael! Your awesome article was very helpful for me.
I’m very excited by your approach, so let me add my $0.02:
1) One item is missed in the post: :exometer should be added to applications list to start automatically.
2) Measurement of query execution time should be changed like that: https://gist.github.com/romul/4a67f4710d6507f78556
Maybe it’s related to changes in Ecto itself, but log function is executed when query already returns a value at the moment.