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

From Tom Lane
Subject Re: clustering by partial indexes
Date
Msg-id 17053.1132078332@sss.pgh.pa.us
Whole thread Raw
In response to Re: clustering by partial indexes  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: clustering by partial indexes  (Bruce Momjian <pgman@candle.pha.pa.us>)
Re: clustering by partial indexes  (Steve Crawford <scrawford@pinpointresearch.com>)
List pgsql-general
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.

            regards, tom lane

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