Re: WIP Patch for GROUPING SETS phase 1

2014-09-09 16:01 GMT+02:00 Robert Haas <robertmhaas(at)gmail(dot)com>:

> On Thu, Aug 21, 2014 at 11:01 AM, Andrew Gierth
> <andrew(at)tao11(dot)riddles(dot)org(dot)uk> wrote:
> >>>>>> "Heikki" == Heikki Linnakangas <hlinnakangas(at)vmware(dot)com> writes:
> > Heikki> Uh, that's ugly. The EXPLAIN out I mean; as an implementation
> > Heikki> detail chaining the nodes might be reasonable. But the above
> > Heikki> gets unreadable if you have more than a few grouping sets.
> >
> > It's good for highlighting performance issues in EXPLAIN, too.
>
> Perhaps so, but that doesn't take away from Heikki's point: it's still
> ugly. I don't understand why the sorts can't all be nested under the
> GroupAggregate nodes. We have a number of nodes already (e.g. Append)
> that support an arbitrary number of children, and I don't see why we
> can't do the same thing here.
>

I don't think so showing sort and aggregation is bad idea. Both can have a
different performance impacts

>
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> Robert Haas
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