Re: WIP Patch for GROUPING SETS phase 1
От | Pavel Stehule |
---|---|
Тема | Re: WIP Patch for GROUPING SETS phase 1 |
Дата | |
Msg-id | CAFj8pRA+uLOQtdko5odT57g1nL-Og_KtY_h2m45sjKKfmd9M0A@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: WIP Patch for GROUPING SETS phase 1 (Robert Haas <robertmhaas@gmail.com>) |
Ответы |
Re: WIP Patch for GROUPING SETS phase 1
|
Список | pgsql-hackers |
2014-09-09 16:01 GMT+02:00 Robert Haas <robertmhaas@gmail.com>:
On Thu, Aug 21, 2014 at 11:01 AM, Andrew Gierth
<andrew@tao11.riddles.org.uk> wrote:
>>>>>> "Heikki" == Heikki Linnakangas <hlinnakangas@vmware.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
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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