On Wed, 10 Jul 2002, [ISO-8859-1] J�rg Schulz wrote:
> Before the column was added explain said:
>
> > explain update test set a='x';
> > Seq Scan on test2 (cost=0.00..20.00 rows=1000 width=6)
>
> (btw: why rows=1000? there are 100.000 rows in the table)
Because you haven't vacuum analyzed since loading the data.
If you're doing an update of every row of a table, you almost
certainly want to at least do a normal vacuum (and possibly
a vacuum analyze) of the table afterwards.
