So one of the items on the TODO list is "Add hash for evaluating GROUP BY aggregates (Tom)"
I'm finding this would benefit a lot of my queries. Most of the time seems to be going into sorts for group by clauses. I don't know how long it would take to build a hash of course, but I suspect it would be less than the sort. Is this something a beginner could figure out? I'm thinking I need a normal Hash node that builds exactly the same kind of hash as a join, then a HashScan node that picks all the rows out of the hash. The neat thing is that hash aggregates would allow grouping on data types that have = operators but no useful < operator. (Incidentally, I'm fond of "nested loop", I remember when I was a beginner SQL programmer looking at plans and it was intuitively obvious what it meant. I suspect for a beginner looking at "nestloop" it might not be quite so obvious.) -- greg ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
