Re: Very strange query difference between 7.3.6 and 7.4.6 (7.3.6 kicking 7.4.6 butt)

"Joshua D. Drake" <jd@commandprompt.com> writes:
> If you look at the second line in each explain it is the sort that is 
> causing the grief.

The aggregation is a great deal worse as well.  I suspect that for some
reason the comparison operations involved in the sorting and grouping
are much slower on the FC3 machine.  What are the data types of the
leading sort keys ... and are you *certain* the FC3 database has
LC_COLLATE and LC_CTYPE set to C?
        regards, tom lane