On Fri, 2006-04-07 at 13:36 -0400, Tom Lane wrote:
> I wrote:
> > Rafael Martinez Guerrero <r.m.guerrero@usit.uio.no> writes:
> >> I have a sql statement that takes 108489.780 ms with 8.0.7 in a
> >> RHEL4/amd64linux server with 2xAMD Opteron(tm) Processor 275 2.00GHz /
> >> 8GB RAM and only 4193.588 ms with 7.4.12 in a RHEL3/386linux server with
> >> 2xIntel(R) Xeon(TM) CPU 2.40GHz / 4GB RAM.
>
> > I think you've discovered a planner regression.
> > Simplified test case using the regression database:
>
> > explain select * from tenk1 a, tenk1 b
> > where (a.ten = b.ten and (a.unique1 = 100 or a.unique1 = 101))
> > or (a.hundred = b.hundred and a.unique1 = 42);
>
> I've repaired the assertion crash in 8.1/HEAD, but I don't think it's
> practical to teach 8.0 to optimize queries like this nicely. The reason
> 7.4 can do it is that 7.4 forces the WHERE condition into CNF, ie
>
[..................]
Tom, thank you very much for your help. As I suspected this was a more
complicated problem than the configuration of some parameters :( . Good
that we have found out this now and not after the upgrade.
All our upgrade plans and testing for all our databases have been done
for/with 8.0.x (yes, I know 8.1.x is much better, but I am working in a
conservative place from the sysadm point of view). We will have to
change our plans and go for 8.1 if we want this to work.
> My recommendation is to update to 8.1.4 when it comes out.
Any idea about when 8.1.4 will be released?
Thanks again.
--
Rafael Martinez, <r.m.guerrero@usit.uio.no>
Center for Information Technology Services
University of Oslo, Norway
PGP Public Key: http://folk.uio.no/rafael/