From: pginfo <pginfo@t1.unisoftbg.com>
To: Bruno Wolff III <bruno@wolff.to>
Cc: pgsql-sql@postgresql.org <pgsql-sql@postgresql.org>
Subject: Re: update and IN vs. EXISTS
Date: Sat, 01 Feb 2003 14:49:46 +0100
Message-ID: <3E3BD07A.CC796690@t1.unisoftbg.com> (raw)
References: <3E3BB210.5C51478C@t1.unisoftbg.com>
<20030201145412.GA29037@wolff.to>
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.
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
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To: pgsql-sql@postgresql.org
Cc: pginfo@t1.unisoftbg.com, bruno@wolff.to
Subject: Re: update and IN vs. EXISTS
In-Reply-To: <3E3BD07A.CC796690@t1.unisoftbg.com>
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