• There are some plans involving the same pairs:

    • AB, BA

    • BC, CB

    • BD, DB

  • Keep the (cheapest) of each group.

  • This is not the same as a greedy algorithm. We aren't keeping the cheapest of the AB, BC, and BD plans.

  • We keep all of them and extend them to 3-table plans.

  • So it's slightly greedy.