Hello everyone I’m studying about http streams and I notice a big difference in performance when returning everything at once and when streaming and that made me think if streaming a big file is really worth it or if there is something wrong with my implementation (most likely that haha) So if anyone could help me understand this situation I’d appreciate a lot. Thanks

non-stream implementation

image1200×481 40.3 KB

  get "/no-stream" do
    pokemons = File.read!("file.json")
    conn |> send_resp(200, pokemons)
  end

Stream implementation :

image1200×477 40.6 KB

  get "/" do

    conn = conn
    |> put_resp_content_type("text/event-stream")
    |> put_resp_header("Access-Control-Allow-Origin", "*")
    |> send_chunked(200)

    File.stream!("file.json")
    |> Jaxon.Stream.from_enumerable
    |> Jaxon.Stream.query([:root, :all])
    |> Stream.map(fn element ->
     {:ok, pokemon}  = Jason.encode(element)
      conn |> chunk(pokemon <> "\n")
    end )
    |> Stream.run

    conn
  end

As you can see the stream implementation has a latency MUCH higher even though the memory peak is a little bit lower. The question here is trying to understand if this is normal or if I messed up somehow I understand if is not possible to achieve the same latency as File.read! but the difference here is so high that made me wonder if something if off

BTW: the lib used to run the load test is called hey