Re: AW: [HACKERS] Re: Let's talk up 6.3 - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: AW: [HACKERS] Re: Let's talk up 6.3
Date
Msg-id 199803301835.NAA18398@candle.pha.pa.us
Whole thread Raw
In response to AW: [HACKERS] Re: Let's talk up 6.3  (Zeugswetter Andreas SARZ <Andreas.Zeugswetter@telecom.at>)
List pgsql-hackers
>
> > Would a rule be that
> > if the first attribute of an index is unique, then additional
> > attributes are basically useless?
>
> For PostgreSQL this is currently true, since indexes are currently not
> used for order by. If you have a unique first column in an index,
> then all following columns could only be used for sorting,
> not for faster access (access actually gets worse).

Sorry, don't follow this logic.  He is not restricting on the first
field of the index, so the index is not used.

--
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

pgsql-hackers by date:

Previous
From: "Vadim B. Mikheev"
Date:
Subject: Re: Let's talk up 6.3
Next
From: Bruce Momjian
Date:
Subject: Re: Let's talk up 6.3