Does Phoenix.Ecto.CheckRepoStatus (callling Ecto.Migrator.migrations/1) need to run under an ecto migration lock?

Oh, that’s interesting. It didn’t occur to me that you simply can turn off migration locking. It works! Just a minor drawback: a migration that concurrently adds an index prints out a warning in this scenario.

It would be great if the CheckRepoStatus plug used this option.