On Fri, 13 Dec 2002, Ing. Gabriel Monsalvo wrote:
> Hi!
> I need help, i mounted a Postgresql server on IBM netserver with RAID 5 134 GB, 2.5 GB de RAM and two Xeon 1.4 ghz.
> I installed postgresql 7.3 in this box, my database have over 25 millons of records, and everything is slow.
> i optimized with indexes,vacuum analyze and tuning up the kernel for shared memory usage.
> but the server is too slow when:
> - create index for any table with more than 5 millions
> - vacuum takes over four hours in this type of tables.
> - select max (field) from table where field2=xxxx takes a lot of time.
>
> explain select max(numoble) from obligacion where periodo=200100;
For this sort of query, I'd suggest trying
select numoble from obligaction where periodo=200100 order by
periodo desc, numoble desc limit 1;
with an index on (periodo, numoble) (I think). You can see messages about
max and min in the archives for me information.