Re: update and IN vs. EXISTS

Bruno Wolff III wrote:

> On Sat, Feb 01, 2003 at 12:40:00 +0100,
>   pginfo <pginfo@t1.unisoftbg.com> wrote:
> >
> > If I try to execute:
> >    update Table1 set fieldForUpdate = 1 where ID IN (select T2.ID from
> > Table2);
> > it is running very slow.
>
> You might try:
>   update Table1 set fieldForUpdate = 1 from Table2 where Table1.id = Table2.id;
>

It is great.It takes 122 sec.
With IN it takes 8000 sec.

> This uses a nonstandard postgres extension and may not be portable, if that
> is a concern.
>

How to resolve the problem with the standart?regards,
iavn.

> INs are being speeded up in 7.4, so the original form might work a lot better
> in the next release.
>
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