Re: Review: Fix snapshot taking inconsistencies

Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi>

From: Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Steve Singer <ssinger_pg@sympatico.ca>, pgsql-hackers@postgresql.org, Alvaro Herrera <alvherre@commandprompt.com>
Date: 2011-02-28T19:18:55Z
Lists: pgsql-hackers
On 2011-02-28 9:03 PM, Tom Lane wrote:
> Marko Tiikkaja<marko.tiikkaja@cs.helsinki.fi>  writes:
>> On 2011-02-28 8:22 PM, Tom Lane wrote:
>>> So: exactly what is the intended behavioral change as of now, and what
>>> is the argument supporting that change?
>
>> The only intended change is what I was wondering in the original post:
>> snapshot handling between normal execution and EXPLAIN ANALYZE when a
>> query expands to multiple trees because of rewrite rules.  Like I said
>> earlier, this is just a bugfix now that wCTEs don't need it anymore.
>
> OK, and which behavior is getting changed, to what?  I am not interested
> in trying to reverse-engineer a specification from the patch.

My recollection is (and the archives seem to agree) that normal 
execution and SQL functions were changed to only advance the CID instead 
of taking a new snapshot.  EXPLAIN ANALYZE and SPI (not exactly sure 
about this one) did that already so they were just changed to use the 
new API.


Regards,
Marko Tiikkaja