Heroku postgres is very slow under load

Question

I'm deploying an app to the Heroku that uses php and heroku-postgres. App performs about 70-80 queries to the small postgres database (about 10Mb).

I did some load testing using apache bench with 50 concurrent requests. And I found that queries execution time is about 5-8 times slower than without any load. Of course, I checked that tables have correct indexes and queries use them.

I also tried different heroku-postgres plans, but the problem still exists.

Answer 1

I also tried different heroku-postgres plans, but the problem still exists.

Make sure the heroku-postgres plan uses the same region as the Heroku app! I spent a week trying to figure out why my app in the EU needed 80ms instead of 0.2ms to query my DB in the US.