Oh, once we hit "beta" fundamental changes like this will be strictly verbotten, even by me.
I would've put this off but after I found out that the "LIKE (tree_sortkey || '%')" hack would always (and properly, I might add) do a sequential scan of all the rows of interest rather than use the index on tree_sortkey I knew I had to fix this. Changing to a "BETWEEN" form worked fine but at that point I realized I could change the representation from text to bit varying without having to change my already-modified queries.
Given that the LANG=C collation dependency was also a significant problem I decided that now was the time to do this. Generating upgrade scripts for a post-first-release-cycle change of this magnitude would be a major PITA (actually PIMA!)
