Re: [HACKERS] Problem with complex query

Hello!

Tom, I want to remind you that you looked into my database and found the
problem was that central.shop_id was int4 but shops.shop_id int2. After
making all fields identical most of the problem was fixed.
I just rerun the query now - and it worked!

On Sun, 9 May 1999, Tom Lane wrote:

> Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us> writes:
> >> SELECT DISTINCT p.subsec_id
> >> FROM central cn, shops sh, districts d, positions p
> >> WHERE cn.shop_id = sh.shop_id AND sh.distr_id = d.distr_id
> >> AND d.city_id = %d AND cn.pos_id = p.pos_id
> >> AND cn.date_i >= current_date - '7 days'::timespan
> >>
> >> While running postgres slowly eats all swap space (30 Meg) and aborts:
>
> > Not sure how to comment on this. Is 6.5beta any better?
>
> Probably not :-(. My guess is that the expression "current_date -
> '7 days'::timespan" is being re-evaluated at each tuple, and since
> we don't yet have intra-statement space recovery, the palloc'd space
> just grows and grows. Oleg, can you try evaluating that expression
> on the application side and sending over a constant instead?
>
> I think being able to recover palloc'd space after every few tuples
> will have to be a top priority for 6.6; we've seen too many complaints
> that trace back to this sort of thing.
>
> regards, tom lane
>

Oleg.
----
Oleg Broytmann http://members.xoom.com/phd2/ phd2(at)earthling(dot)net
Programmers don't die, they just GOSUB without RETURN.