Client Connection Vars with Ecto

Postgres has dozens of connection variables it will take, a couple of my favorite ones are statement_timeout and application_name.

Ecto takes a parameters connection option, which is a keyword list of connection parameters.

# dev.exs

...

# Configure your database
config :myapp, Myapp.Repo,
  adapter: Ecto.Adapters.Postgres,
  database: "myapp_dev",
  socket_dir: "/var/run/postgresql",
  parameters: [application_name: "My App Development", statement_timeout: "5000"],
  pool_size: 10

Example of statement_timeout being respected in Ecto:

Ecto.Adapters.SQL.query!(Myapp.Repo, "select pg_sleep(86400)")

** (Postgrex.Error) ERROR 57014 (query_canceled): canceling statement due to statement timeout
    (ecto) lib/ecto/adapters/sql.ex:200: Ecto.Adapters.SQL.query!/5

Client Connection Variables references: https://www.postgresql.org/docs/current/static/runtime-config-client.html