Re: Poor performance using CTE

On Wed, Nov 21, 2012 at 1:24 PM, Andres Freund <andres@2ndquadrant.com> wrote:
> 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.

set collapse_cte_limit=8;
with blah as (blah) select blah;

Not global at all.