with_advisory_lock

# File activerecord/lib/active_record/migration.rb, line 1293
    def with_advisory_lock
      lock_id = generate_migrator_advisory_lock_id
      got_lock = Base.connection.get_advisory_lock(lock_id)
      raise ConcurrentMigrationError unless got_lock
      load_migrated # reload schema_migrations to be sure it wasn't changed by another process before we got the lock
      yield
    ensure
      Base.connection.release_advisory_lock(lock_id) if got_lock
    end