Perez wrote: > I thought, from watching the list for a while, that the planner > statistics needed were known but that how to gather the statistics > was not?

I think over the course of the discussion we have figured out that we would like to have cross-column correlation statistics. The precise mathematical incarnation hasn't been determined yet, as far as I can see. Collecting the statistics thereafter isn't that hard, but there needs to be a way to not collect an exponential volume of statistics on all column combinations. -- Peter Eisentraut http://developer.postgresql.org/~petere/ ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match