Re: Why queries takes too much time to execute?

>     Well, i have a very large database, with vary tables and very 
> registers. Every day, too many operations are perfomed in that DB, with 
> queries that insert, delete and update. Once a week some statistics are 
> collected using vacuum analyze.

Have vacuum analyze running once an HOUR if it's very busy.  If you are 
using 7.4, run the pg_autovacuum daemon that's in contrib/pg_autovacuum.

>     The problem is after a period of time (one month, i think), the 
> queries takes too much time to perform. A simple update can take 10 
> seconds or more to perform.

If running vacuum analyze once an hour doesn't help, try running a 
vacuum full once a week or something to fix the problem.

Also, try upgrading to 7.4 which has indexes that won't suffer from bloat.

Chris