Re: clustering by partial indexes

Поиск
Список
Период
Сортировка
От Steve Crawford
Тема Re: clustering by partial indexes
Дата
Msg-id 200511151018.27124.scrawford@pinpointresearch.com
обсуждение исходный текст
Ответ на Re: clustering by partial indexes  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: clustering by partial indexes  ("Jim C. Nasby" <jnasby@pervasive.com>)
Список pgsql-general
On Tuesday 15 November 2005 10:12, Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Tom Lane wrote:
> >> CLUSTER says "order the table according to the order of the
> >> entries in this index".  A partial index doesn't define an
> >> ordering for the whole table, only the rows that have entries in
> >> that index.  So it doesn't seem to me that you are asking for
> >> something that has a well defined meaning.
> >
> > I assume it would cluster the part of the table covered by the
> > partial index, and the rest of the table would be in any order.
> > It seems like reasonable behavior, though this is the first
> > request I can remember.
>
> But what is the point?  You might as well cluster by a full index.
>
> This is *not* trivial to implement, btw, so one request with no
> justification should not be enough to get it on the TODO list.

Not trivial? Seems to me more like impossible to implement for the
general case which would require you to resolve the situation where
someone requests multiple, overlapping, clustered partial indexes
where the ordering requirements are in conflict.

Cheers,
Steve

В списке pgsql-general по дате отправления:

Предыдущее
От: Berend Tober
Дата:
Сообщение: Most significant digit number formatting
Следующее
От: Bruce Momjian
Дата:
Сообщение: Re: Number of items in a cursor...