Execution variability

Hi all.
I understand this can be a ridiculous question for most you.

The very same query on the very same db shows very variable timings.
I'm the only one client on an unpupolated server so I'd expect a
rather constant timing.

INstead for a while the query become very slooow and the CPU reached
60 to 70% and the time needed is about 1.5 minutes0.
Again with just me on it.
Normally the same query rises the usage to a mere 5% to 7% with timing
with the tenth of a second.

I have disable both the autovacuum and the "stats_start_collector" in
the
attempt to disable possibe reasons for slow down. No luck in this.

Do you have any hint?

--
Vincenzo Romano
--
Maybe Computer will never become as intelligent as Humans.
For sure they won't ever become so stupid. [VR-1988]