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Re: AW: [HACKERS] Re: Let's talk up 6.3

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: Andreas(dot)Zeugswetter(at)telecom(dot)at (Zeugswetter Andreas SARZ)
Cc: raines(at)SLAC(dot)Stanford(dot)EDU, pgsql-hackers(at)hub(dot)org
Subject: Re: AW: [HACKERS] Re: Let's talk up 6.3
Date: 1998-03-30 18:35:34
Message-ID: 199803301835.NAA18398@candle.pha.pa.us (view raw or flat)
Thread:
Lists: 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(at)candle(dot)pha(dot)pa(dot)us              |  Drexel Hill, Pennsylvania 19026
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