[HACKERS] [Bizgres-general] A Guide to Constraint Exclusion

[Simon Riggs]

On Thu, 2005-07-14 at 15:30 -0400, Greg Stark wrote:
> Hannu Krosing <hannu at tm.ee> writes:
> 
> > > It is not yet possible to specify that an inheritance parent has no
> > > rows, and, if so, should always be excluded from the query.
> > 
> > I think that a simple "CHECK(false)" constraint should be enough for
> > this.
> 
> huh, that's clever.

But not clever enough... see my reply to Hannu. Sorry.

> > > CE checks are not made when the parent table is involved in a join.
> > 
> > Is this also the case where parent table is inside subquery and that
> > subquery is involved in a join?
> 
> I assume this is a TODO and just not in your first batch of work? It seems
> like a pretty important piece eventually. Are there any fundamental
> difficulties with handling joins eventually? 

Its a reasonable size piece of work, and could not be reworked in time
for 8.1.

Some other mental leaps may also be required.

Best Regards, Simon Riggs