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List:       postgresql-general
Subject:    Re: [GENERAL] Re: Data warehousing
From:       Herouth Maoz <herouth () oumail ! openu ! ac ! il>
Date:       1999-06-29 9:38:00
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At 16:00 +0300 on 28/06/1999, Chris Bitmead wrote:


> Why do multi-field indexes? Umm. How about to avoid doing a sequential
> scan? If your query depends on multiple fields then once you've found
> the set based on the first index you would have to sequential scan that
> subset based on the second condition, unless you have a multi-field
> index.

Well, I may be wrong, but I seem to recall reading in one of these mailing
lists once that there is no real difference performance-wise between
multiple-field indices and single-field indices on same columns. There was
a bit of overhead. I think Vadim should know the answer to this question.

Herouth

--
Herouth Maoz, Internet developer.
Open University of Israel - Telem project
http://telem.openu.ac.il/~herutma

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