Re: Writable foreign tables: how to identify rows

On Wed, Mar 6, 2013 at 12:06 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> On the other hand, I don't have a problem with decreeing that
> non-Postgres FDWs need to use PK row identification in the first
> release; which would be the consequence if we don't do anything about
> allowing new system columns in 9.3. We will certainly need that style
> of row identification to be written and tested anyway. It won't stop
> us from extending things later.

Oh, I didn't realize that was how it was going to work out. That
seems very reasonable to me. There is a performance problem with
forcing DELETE FROM ft WHERE nonkey = 5 to be pushed to the remote
side as SELECT pk FROM ft WHERE nonkey = 5 followed by DELETE FROM ft
WHERE pk = $1 for each pk value returned by the SELECT, which sounds
like it's what will happen under this system. But I don't have any
problem leaving that as future work.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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