Kim Bisgaard <kib+pg@xxxxxx> writes: > The reason the first query is not performing is because the query > optimizer does not push the conditions down into the sub-queries - right?? Well, it's not the same condition: the WHERE clause is constraining the output variable of the FULL JOIN, which is logically and implementationally distinct from either input table's variable. I suppose it is arguable that we could transform the WHERE clause into constraints on the input variables --- but we'd have to think carefully about the conditions under which such a transformation is valid. Offhand it seems like it might work for strict non-volatile constraint expressions that refer only to output variables of the JOIN; if they refer to other tables too then I'm not sure. This is by no means a "bug fix", but if I have time over the next week I'll see whether it is feasible to write for 8.1. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
