"Vlad Marchenko" <marchenko@gmail.com> writes:
> I'm curious if that new hash aggregation algorithm was put in 8.3 with the
> performance increase as a goal
Yes.
http://archives.postgresql.org/pgsql-hackers/2007-05/msg01179.phphttp://archives.postgresql.org/pgsql-committers/2007-06/msg00007.php
(and nearby messages)
> or it was simply a required change to support
> some other new feature of 8.3? Right now the switch from 8.2 to 8.3 doesn't
> seems a favorable step for the type of application that we have...
You are condemning a demonstrably better algorithm on the basis of one
test case. If you poke around a bit harder you will find other cases
where it is faster than 8.2 because of having better distribution.
regards, tom lane