On Thu, Oct 12, 2006 at 09:52:11AM +0200, Dawid Kuroczko wrote: > Recently I've been playing with quite a big table (over 50mln rows), > and did some SELECT ... sum(...) WHERE ... GROUP BY ... queries. > > The usual plan for these is to sort the entries according to GROUP BY > specification, then to run aggregates one by one. If the data to be > sorted is large enough, PostgreSQL has no other option than to spill > to disk, which well, Isn't the fastest...
<snip> Sounds an awful lot like the HashAggregate nodetype which has existed since at least 7.4. It has a hashtable of "keys" with attached "states". Hope this helps, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > From each according to his ability. To each according to his ability to > litigate.
signature.asc
Description: Digital signature
