Re: Using FDW AddForeignUpdateTargets for a hidden pseudo-column - Mailing list pgsql-hackers

From Bernd Helmle
Subject Re: Using FDW AddForeignUpdateTargets for a hidden pseudo-column
Date
Msg-id 1604F4E93D96BC049CF1FB4C@eje.land.credativ.lan
Whole thread Raw
In response to Re: Using FDW AddForeignUpdateTargets for a hidden pseudo-column  (Albe Laurenz <laurenz.albe@wien.gv.at>)
Responses Re: Using FDW AddForeignUpdateTargets for a hidden pseudo-column  (Aleksey Demakov <a.demakov@postgrespro.ru>)
Re: Using FDW AddForeignUpdateTargets for a hidden pseudo-column  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers

--On 14. Juni 2016 10:32:13 +0000 Albe Laurenz <laurenz.albe@wien.gv.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



pgsql-hackers by date:

Previous
From: Amit Kapila
Date:
Subject: Re: ERROR: ORDER/GROUP BY expression not found in targetlist
Next
From: Aleksey Demakov
Date:
Subject: Re: Using FDW AddForeignUpdateTargets for a hidden pseudo-column