Re: out-of-order caution

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: out-of-order caution
Date: 2011-10-27 15:55:07
Message-ID: CA+U5nM+GEcz+u8mW4dALia_aRZstD_8d_LLvNc8bOb126M0U9w@mail.gmail.com
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On Thu, Oct 27, 2011 at 4:41 PM, Kevin Grittner
<Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
> On the docs page for the SELECT statement, there is a caution which
> starts with:
>
> | It is possible for a SELECT command using ORDER BY and FOR
> | UPDATE/SHARE to return rows out of order. This is because ORDER BY
> | is applied first.
>
> Is this risk limited to queries running in READ COMMITTED
> transactions?  If so, I think that should be mentioned in the
> caution.

I think it should say that if this occurs with SERIALIZED transactions
it will result in a serialisation error.

Just to say there is no effect in serializable mode wouldn't be helpful.

--
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

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