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From: Scott Lamb <[email protected]>
To: Steve Wampler <[email protected]>
Cc: Postgres-performance <[email protected]>
Subject: Re: Help speeding up delete
Date: Mon, 14 Nov 2005 15:20:21 -0800
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>

On Nov 14, 2005, at 2:07 PM, Steve Wampler wrote:
> # SELECT at.id FROM "tmp_table2" at, "tmp_tabl2e" a
> #   WHERE at.id=a.id and a.name='obsid' and a.value='oid080505';

Isn't this equivalent?

select id from tmp_table2 where name = 'obsid' and value = 'oid080505';

> # DELETE FROM "tmp_table2" WHERE id IN
> # (SELECT at.id FROM "tmp_table2" at, "tmp_table2" a
> #   WHERE at.id=a.id and a.name='obsid' and a.value='oid080505');

and this?

delete from tmp_table2 where name = 'obsid' and value = 'oid080505';

Why are you doing a self-join using id, which I assume is a primary key?

-- 
Scott Lamb <http://www.slamb.org/;

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