+1 to this - I've griped pretty often that FastAPI's documentation implicitly recommends this (https://fastapi.tiangolo.com/tutorial/sql-databases/#create-...) by suggesting using dependency injection to manage database connections, only to start seeing connection pool exhausted errors as soon as the number of concurrent requests exceeds the number of allowed connections.

▲ frollogaston 12 hours ago | parent [-]

Oh wow. Dep injection for DB connections is nasty.

▲ alfons_foobar 11 hours ago | parent [-]

I might be outing myself as a noob here, but... what is the (better) alternative?

▲ 0x696C6961 11 hours ago | parent [-]

You inject the pool itself.

	▲	alfons_foobar 39 minutes ago \| parent [-]
		Sorry, I am being dense... how does that solve the problem? I still have to get a connection from the pool, I just do it inside the function body now, right? So this `@app.get("/users") def get_users(conn = Depends[get_db_conn]): users = conn.execute("SELECT * FROM users") return users` would become that instead: `@app.get("/users") def get_users(pool = Depends[get_db_pool]): with pool.get_conn() as conn: users = conn.execute("SELECT * FROM users") return users` But I still need enough connections in the pool to handle all concurrent requests, no?