On Fri, Jan 20, 2006 at 07:23:10PM -0500, Tom Lane wrote:
> I'm not very clear on what tsearch2 is doing with these bitmaps, but it
> looks like an upper page's downlink has the union (bitwise OR) of the
> one-bits in the values on the lower page, and you have to visit the lower
> page if this union has a nonempty intersection with the set you are looking
> for. If that's correct, what you really want is to divide the values so
> that the unions of the two sets have minimal overlap ... which seems to me
> to have little to do with what the code does at present.
Sort of like the vertex-cover problem? That's probably a lot harder than
finding the two farthest points...
/* Steinar */