🔗 Elixir DBConnection pooling deep dive

DBConnection.ConnectionError: connection not available and request was dropped from queue after 2290ms. This means requests are coming in and your connection pool cannot serve them fast enough. You can address this by:

  1. By tracking down slow queries and making sure they are running fast enough
  2. Increasing the pool_size (albeit it increases resource consumption)
  3. Allow requests to wait longer by increasing :queue_target and :queue_interval

See DBConnection.start_link/2 for more information

It is pretty common to run unto this error as an Elixir developer working with relational databases. The suggested fixes definitely help, but personally I feel bad tweaking something I don't understand.

How does changing pool_size actually affect the rest of the application? I want to keep my mysteries to Saturday morning cartoons, not production. So I decided to dig in and see how pooling works.