From: Andres Freund <andres@anarazel.de>
To: pgsql-hackers@postgresql.org
Subject: Re: Creation of temporary tables on read-only standby servers
Date: Mon, 18 Oct 2010 21:17:24 +0200
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Cc: Tom Lane <tgl@sss.pgh.pa.us>,
 Bruce Momjian <bruce@momjian.us>
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	<22902.1287425161@sss.pgh.pa.us>
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On Monday 18 October 2010 20:06:01 Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > Currently it isn't possible to create temporary tables on read-only
> > standby servers, and I don't see it listed on the TODO list.  Can I add
> > it?
> 
> Not unless you have some credible concept for how it might ever be
> implemented.  You can't create temp tables because you can't modify
> system catalogs, and if you did somehow create them you couldn't put
> anything in them because you can't generate XIDs on a slave ... much
> less commit them.  We have talked about ways that temp tables might be
> created without touching the "real" system catalogs, but the XID issue
> seems a complete showstopper.
Hm. Wouldnt it be possible to use virtual xids for that purpose? They are 
never seen outside of that session anyway...

Andres