Re: [HACKERS] COPY with no WAL, in certain circumstances - Mailing list pgsql-patches

From Simon Riggs
Subject Re: [HACKERS] COPY with no WAL, in certain circumstances
Date
Msg-id 1168193727.3951.130.camel@silverbirch.site
Whole thread Raw
In response to Re: [HACKERS] COPY with no WAL, in certain circumstances  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-patches
On Sun, 2007-01-07 at 11:29 -0500, Tom Lane wrote:
> I wrote:
> > ... The active-portal kluge that you've just
> > mentioned is nothing but a kluge, proving that you thought of some cases
> > where it would fail.  But I doubt you thought of everything.
>
> BTW, a sufficient counterexample for that kluge is that neither SPI or
> SQL-function execution use a separate portal for invoked commands.  Thus
> testing whether there's only one active portal isn't sufficient to prove
> that you're not inside a function executing in serializable mode, and
> thus it could have a transaction snapshot predating the COPY.

Chewing the last pieces of my Bowler hat while reading. I don't have
many left ;-(

> It's conceivable that it's safe anyway, or could be made so with some
> rejiggering of the tests in tqual.c, but counting active portals doesn't
> do anything to help.

I'll rethink, but as you say, with separate proposal and patch.

--
  Simon Riggs
  EnterpriseDB   http://www.enterprisedb.com



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