| From: | Bernd Helmle <mailings(at)oopsware(dot)de> |
|---|---|
| To: | Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>, 'Aleksey Demakov *EXTERN*' <a(dot)demakov(at)postgrespro(dot)ru>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Using FDW AddForeignUpdateTargets for a hidden pseudo-column |
| Date: | 2016-06-14 12:46:06 |
| Message-ID: | 1604F4E93D96BC049CF1FB4C@eje.land.credativ.lan |
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| Lists: | pgsql-hackers |
--On 14. Juni 2016 10:32:13 +0000 Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>
wrote:
> I first thought of using the internal ROWID column that's probably
> similar to your case, but that wouldn't fit into a tid's 6 bytes, and I
> found that I could only add resjunk columns for existing columns of the
> table.
> Making the internal ROWID an explicit column in the foreign table seemed
> just too ugly.
The Informix FDW uses SelfItemPointerAttributeNumber. Luckily the Informix
ROWID is a 4 byte encoded identifier (3 first significant bytes are the
logical page number, last significant bytes is the slot number within that
page). Maybe you can find a way of logically addressing your data, too? It
only needs to fit within 6 bytes, afaik.
--
Thanks
Bernd
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