From: Ludwig Lim <lud_nowhere_man@yahoo.com>
To: Keith Gray <keith@heart.com.au>
Cc: PostgreSQL Mailing List <pgsql-sql@postgresql.org>
Subject: Re: Slow performance on MAX(primary_key)
Date: Tue, 15 Oct 2002 00:16:28 -0700 (PDT)
Message-ID: <20021015071628.57518.qmail@web80304.mail.yahoo.com> (raw)
In-Reply-To: <3DABA146.7010902@heart.com.au>
Hi Keith:
--- Keith Gray <keith@heart.com.au> wrote:
> Help,
>
> I have just been comparing some large table
> performance
> under 7.1 using the
>
> select max(primary key)from table;
>
> We are using this for various functions including
> sequence.
>
Try using the following as alternative :
SELECT primary_key
FROM table
ORDER BY primary_key desc
LIMIT 1;
This should work if primary_key is indexes.
As of now, Max() doesn't utilizes the indices hence
it always do a sequential scan.
Hope that helps,
regards,
ludwig.
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To: pgsql-sql@postgresql.org
Cc: lud_nowhere_man@yahoo.com, keith@heart.com.au
Subject: Re: Slow performance on MAX(primary_key)
In-Reply-To: <20021015071628.57518.qmail@web80304.mail.yahoo.com>
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