Re: Rewrite, normal execution vs. EXPLAIN ANALYZE
David Fetter <david@fetter.org>
From: David Fetter <david@fetter.org>
To: Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi>
Cc: pgsql-hackers@postgresql.org
Date: 2010-07-23T17:52:39Z
Lists: pgsql-hackers
On Thu, Jul 22, 2010 at 08:43:35PM +0300, Marko Tiikkaja wrote: > Hi, > > From the code I understood that when executing a query "normally", > in READ COMMITTED mode, we take a new snapshot for every query that > comes out of rewrite. But in an EXPLAIN ANALYZE, we only update the > CID of the snapshot taken when the EXPLAIN started. > > 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? Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate