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help / color / mirror / Atom feedFrom: Vik Fearing <vik.fearing@dalibo.com>
To: Herouth Maoz <herouth@unicell.co.il>
To: pgsql-sql@postgresql.org
Subject: Re: An archiving query - is it safe?
Date: Tue, 14 Jan 2014 13:55:23 +0100
Message-ID: <52D533BB.5030602@dalibo.com> (raw)
In-Reply-To: <671916D8-6897-4D4F-940C-3FFF61D67513@unicell.co.il>
References: <671916D8-6897-4D4F-940C-3FFF61D67513@unicell.co.il>
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On 01/14/2014 12:06 PM, Herouth Maoz wrote:
> I have regular archiving scripts which traditionally did something like this
>
> BEGIN TRANSACTION;
> INSERT INTO a__archive
> SELECT * FROM a
> WHERE <condition>; -- date range condition
>
> DELETE FROM a
> WHERE <condition>; -- same date range condition
> COMMIT;
>
> This is "classic" SQL. I'm thinking of changing this into something like:
>
> WITH del AS ( DELETE FROM a WHERE <condition> RETURNING * )
> INSERT INTO a__archive SELECT * FROM del;
>
> As this would only access table "a" once, deleting and returning the records in the same access, which I believe will be more efficient.
>
> Is this safe to do? Is there any danger of losing data? Is it atomic?
Yes. No. Yes.
--
Vik
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To: pgsql-sql@postgresql.org
Cc: vik.fearing@dalibo.com, herouth@unicell.co.il
Subject: Re: An archiving query - is it safe?
In-Reply-To: <52D533BB.5030602@dalibo.com>
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