Filtering with Computed Columns Hanging

[robertervin]

Plywood.ply()
.apply("my_datasource", $("my_datasource")
      .filter(
        $("timestamp").in({
          start: new Date("2018-01-01"),
          end: new Date("2018-02-16")
        })
      )
      .apply('visitorTypes', $("my_datasource")
             .split({ UserId: '$user__id' })
             .apply('user__is_new', $("my_datasource").max('$user__is_first_session'))
       )
      .filter($('user__id').in(
        $('visitorTypes').filter('$user__is_new == 1').collect('$UserId')
      ))
)
.apply("count", $("my_datasource").count())

Never resolves (from the 2min wait time I gave it) on a 100k row dataset