Re: Poor performance using CTE - Mailing list pgsql-performance

From Andres Freund
Subject Re: Poor performance using CTE
Date
Msg-id 20121121162416.GA6268@awork2.anarazel.de
Whole thread Raw
In response to Re: Poor performance using CTE  (Claudio Freire <klaussfreire@gmail.com>)
Responses Re: Poor performance using CTE
List pgsql-performance
On 2012-11-21 13:16:25 -0300, Claudio Freire wrote:
> On Wed, Nov 21, 2012 at 12:32 PM, Andres Freund <andres@anarazel.de> wrote:
> > +1
> >
> > WITH foo AS (SELECT ...) (barrier=on|off)?
> >
> > 9.3 introduces the syntax, defaulting to on
> > 9.4 switches the default to off.
>
> Why syntax? What about a guc?
>
> collapse_cte_limit?

Because there are very good reasons to want to current behaviour. A guc
is a global either/or so I don't see it helping much.

Greetings,

Andres Freund

--
 Andres Freund                       http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


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