Re: DELETE with LIMIT (or my first hack)

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От Jeff Davis
Тема Re: DELETE with LIMIT (or my first hack)
Дата
Msg-id 1291155667.11789.6.camel@jdavis-ux.asterdata.local
обсуждение исходный текст
Ответ на Re: DELETE with LIMIT (or my first hack)  (Robert Haas <robertmhaas@gmail.com>)
Список pgsql-hackers
On Tue, 2010-11-30 at 15:52 -0500, Robert Haas wrote:
> On Tue, Nov 30, 2010 at 2:45 PM, Jeff Davis <pgsql@j-davis.com> wrote:
> > On Tue, 2010-11-30 at 11:12 -0500, Robert Haas wrote:
> >>
> >> Could you possibly have ModifyTable -> Limit -> MergeAppend?
> >
> > Before MergeAppend knows which tuple to produce, it needs to see the
> > tuples (at least the first one from each of its children), meaning that
> > it needs to pull them through ModifyTable; and at that point it's
> > already too late.
> >
> 
> You seem to be imagining the MergeAppend node on top

Yes, I assumed that the tuples flowed in the direction of the arrows ;)

Now that I think about it, your representation makes some sense given
our EXPLAIN output.

Regards,Jeff Davis



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