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

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От Bruce Momjian
Тема Re: AW: [HACKERS] Re: Let's talk up 6.3
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Msg-id 199803301835.NAA18398@candle.pha.pa.us
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Ответ на AW: [HACKERS] Re: Let's talk up 6.3  (Zeugswetter Andreas SARZ <Andreas.Zeugswetter@telecom.at>)
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>
> > 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.

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