Re: clustering by partial indexes - Mailing list pgsql-general

From Bruce Momjian
Subject Re: clustering by partial indexes
Date
Msg-id 200511151813.jAFIDJt13583@candle.pha.pa.us
Whole thread Raw
In response to Re: clustering by partial indexes  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
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.

But I assume they created a partial index because they didn't want 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.

Yea, that is the real issue I was alluding to.

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