Excerpts from Marko Tiikkaja's message of vie jul 23 14:13:18 -0400 2010: > On 7/23/2010 8:52 PM, David Fetter wrote: > > On Thu, Jul 22, 2010 at 08:43:35PM +0300, Marko Tiikkaja wrote: > >> Did I misunderstand the code? And if I didn't, why do we do this > >> differently? > > > > You mentioned in IRC that this was in aid of getting wCTEs going. How > > are these things connected? > > Currently, I'm trying to make wCTEs behave a bit like RULEs do. But if > every rewrite product takes a new snapshot, wCTEs will behave very > unpredictably.
I don't think it's fair game to change the behavior of multiple-output rules at this point. However, I also think that it's unwise to base wCTEs on the behavior of rules -- rules are widely considered broken and unusable for nontrivial cases. Also, I think that having a moving snapshot for the different parts of a wCTE is going to mean they're unpredictable. For predictable usage you'll be forcing the user to always wrap them in SERIALIZABLE transactions. In short I think a wCTE should only advance the CID, not get a whole new snapshot. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
