Re: Review: Fix snapshot taking inconsistencies

On Mon, Feb 28, 2011 at 1:45 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Mon, Feb 28, 2011 at 1:22 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> So: exactly what is the intended behavioral change as of now, and what
>>> is the argument supporting that change?
>
>> IIUC, this is the result of countless rounds of communal bikeshedding around:
>
> Quite :-(.  But I'm not sure where the merry-go-round stopped.
>
>> http://archives.postgresql.org/pgsql-hackers/2010-07/msg01256.php
>
> Please notice that the very terms of discussion in that message depend
> on a view of wCTEs that has got nothing to do with what was applied.
> I'm afraid that the goals of this patch might be similarly obsolete.

No, I don't think so.  IIUC, the problem is that EXPLAIN ANALYZE runs
the rewrite products with different snapshot handling than the regular
execution path.  So in theory you could turn on auto_explain and have
the semantics of your queries change.  That would be Bad.

--
Robert Haas
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