Comment by reissbaker
1 day ago
I think 500ms P75 is good for an app that hits network in a hot path (mobile networks are no joke), but I agree that 200ms is very very bad for hitting the DB on the backend. I've managed apps with tables in the many, many billions of rows in MySQL and would typically expect single digit millisecond responses. If you use EXPLAIN you can quickly learn to index appropriately and adjust queries when necessary.
500ms p75 is not good for the (low) complexity of the shopify app.
Also reporting p75 latency instead of p99+ just screams to me that their p99 is embarrassing and they chose p75 to make it seem reasonable.