See blog post N+1 problem by misusing Phoenix PubSub and how to spot it with OpenTelemetry.

Start Zipkin

docker run -d -p 9411:9411 openzipkin/zipkin

Set OTEL_SERVICE_NAME environment variable

export OTEL_SERVICE_NAME=acme

Start your Phoenix server:

• Install dependencies with mix deps.get
• Create and migrate your database with mix ecto.setup
• Start Phoenix endpoint with mix phx.server or inside IEx with iex -S mix phx.server

Now you can visit localhost:4000/orders.

• Create an order.
• Open the order page in multpile browser windows (to get multiple concurrent liveview connections established).
• Edit the order in one window and confirm that it was updated in other windows.
• Go to Zipkin localhost:9411/zipkin.
• Add tagQuery in search tagQuery=broadcaster and Run Query.
• Observe traces and spands.

Learn more

• Official OpenTelemetry website: https://opentelemetry.io
• Official Zipkin website: https://zipkin.io
• Official phoenix website: https://www.phoenixframework.org/
• Phoenix guides: https://hexdocs.pm/phoenix/overview.html
• Phoenix docs: https://hexdocs.pm/phoenix
• Forum: https://elixirforum.com/c/phoenix-forum
• Source: https://github.com/phoenixframework/phoenix