Fernando Mertins wrote:
> I have a PostgreSQL 8.3.6
You should consider upgrading to the latest minor release:
http://www.postgresql.org/support/versioning
http://www.postgresql.org/docs/8.3/static/release.html
> My question is, this same query executes many times a day and many
> times fast/normal, but why in some cases its run slowly? Especialy
> because the "CODCURSO" column is PK and this table has only 3
> registers (tiny table).
Two common causes for this are blocking and overloading the I/O
system at checkpoint. You might want to turn on logging of
checkpoints to see if this happens only during checkpoints. See this
page for techniques to look at blocking:
http://wiki.postgresql.org/wiki/Lock_Monitoring
If neither of these helps, please review this page and post again
with more details:
http://wiki.postgresql.org/wiki/Guide_to_reporting_problems
-Kevin