On Thu, Nov 11, 2010 at 1:53 PM, David Fetter <da...@fetter.org> wrote: > On Thu, Nov 11, 2010 at 12:36:38PM -0500, Merlin Moncure wrote: >> On Thu, Nov 11, 2010 at 12:13 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> > then the conclusion is foregone. To my mind, they should be thought of >> > as running in parallel, or at least in an indeterminate order, just >> > exactly the same way that different data modifications made in a single >> > INSERT/UPDATE/DELETE command are considered to be made simultaneously. >> >> +1 > > -1. > > When people want to see what has gone before, they can use RETURNING > clauses. With the "indeterminate order" proposal, they cannot.
If you want to see what happened 'before' you *must* use a returning clause. It's the link that pipelines data from one query to another. There is in fact no 'before', just a way to define hook output into input. ISTM you have a lot more available routes of CTE optimization if you go this way. but, can you present an example of a case that depends on execution order w/o returning? maybe I'm not seeing something... merlin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
