Re: BUG #6572: The example of SPI_execute is bogus

On Sun, Apr 15, 2012 at 12:29 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> I think it would be a good idea for UPDATE and DELETE to expose
>> a LIMIT option, but I can't really see the virtue in making that
>> functionality available only through SPI.
>
> FWIW, I'm not excited about that.  You can get well-defined behavior
> today from a SELECT/LIMIT drawing from a writable CTE (namely, that
> the UPDATE/DELETE runs to completion but you only see a subset of
> its RETURNING result).  LIMIT directly on the UPDATE/DELETE would be
> ill-defined, unless perhaps you want to also invent a way of specifying
> the order in which rows get selected for update; but I don't want to
> go there.

In the use cases I'm thinking of, it doesn't matter which row you
decide to update or delete, only that you pick a single one.

--
Robert Haas
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