> Yes, you are right but it wasn't the case this time, I have run the
explain plenty of
> times with same results. I think that the reason was that I made a simple
VACUUM,
> after a VACUUM FULL ANALYZE (1h!!) things are ok
It's reasonable to expect that a seq scan will perform faster after a full
vacuum, as the physical size and organization of the table has been changed.
I wouldn't expact a plain vacuum to have any tangible affect on performance,
for the better or for the worse..
I'd like to know more about the possibility of plain vacuums harming
performance. This is the first I've heard of it. Vacuum full is not always
an option in a production environment.