| From: | Marko Tiikkaja <marko(at)joh(dot)to> |
|---|---|
| To: | Etsuro Fujita <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Rukh Meski <rukh(dot)meski(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: LIMIT for UPDATE and DELETE |
| Date: | 2014-09-10 07:57:49 |
| Message-ID: | 5410047D.8010109@joh.to |
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| Lists: | pgsql-hackers |
On 2014-09-10 04:25, Etsuro Fujita wrote:
> (2014/09/09 18:57), Heikki Linnakangas wrote:
>> What's not clear to me is whether it make sense to do 1) without 2) ? Is
>> UPDATE .. LIMIT without support for an ORDER BY useful enough? And if we
>> apply this patch now, how much of it needs to be rewritten after 2) ? If
>> the answers are "yes" and "not much", then we should review this patch
>> now, and put 2) on the TODO list. Otherwise 2) should do done first.
>
> My answers are "yes" but "completely rewritten".
Any particular reason for you to say that? Because an UPDATE might have
a RETURNING clause, all the updated tuples have to go through the
ModifyTable node one at a time. I don't see why we couldn't LIMIT there
after implementing #2.
.marko
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