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:
> Tom Lane wrote:
>> 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 ... 
>> 
> Data types are:

> post_id integer
> topic_id integer
> topic_title character(255) (I have no idea why ;))

> forum_status and forum_id are smallints...

> The rest are pretty basic integers.

Hm.  What is the data like --- in particular, are the topic_ids unique
in the data processed by the sort?  I'm wondering how often the
sort/group comparisons would even look at columns beyond the first
two ...
        regards, tom lane