Re: Implement targetlist SRFs using ROWS FROM() (was Changed SRF in targetlist handling)

On 2016-09-02 10:34:54 -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > On 2016-09-02 10:20:42 -0400, Tom Lane wrote:
> >> ... ISTM all we
> >> need is that the SRF be on the inside of the join, which is automatic
> >> if it's LATERAL.
> 
> > Right. But there's nothing to force a lateral reference to be there
> > intrinsically. I've added a "fake" lateral reference to the ROWS FROM
> > RTE to the subquery, when there's none otherwise, but that's not
> > entirely pretty.
> 
> Hm, do you get cases like this right:
> 
>     select generate_series(1, t1.a) from t1, t2;
> 
> That would result in a lateral ref from the SRF RTE to t1, but you really
> need to treat it as laterally dependent on the join of t1/t2 in order to
> preserve the old semantics.  That is, you need to be laterally dependent
> on the whole FROM clause regardless of which variable references appear.

Yes - as the original query is moved into a subquery, the lateral
dependency I force-add simply is to the entire subquery atm (as a
wholerow var).