Re: update ... from where id in (..) question

> I have a table with approx.  2mln records.
>
> There were a few for which I had to update statusfield, so I did:
>
>         update table set statusflag = 'U' where id in ('id10', 'id20',
> 'id30');
>
> this took so long that I cancelled it, and used separate
>
>         update table set statusflag = 'U' where id = 'id10';
>
> statements, which were executed in a fraction of a second.
>
>
> Has someone an explanation for this ?

http://www.postgresql.org/docs/faq-english.html#4.23