Re: [SQL] quest:optimization with indexes

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От Ross J. Reedstrom
Тема Re: [SQL] quest:optimization with indexes
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Msg-id 19990811091257.A2912@wallace.ece.rice.edu
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Ответ на Re: [SQL] quest:optimization with indexes  (Herouth Maoz <herouth@oumail.openu.ac.il>)
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On Wed, Aug 11, 1999 at 04:30:13PM +0300, Herouth Maoz wrote:
> At 01:42 +0300 on 11/08/1999, Clayton Cottingham wrote:
> >
> > where/what rules should be followed for setting up a good indexing
> > scheme under pg?
> 
<snipped Herouth's good summation of the rules of indices>

One thing to add: after adding your index, vacuum analyze you table, or else
the optimizer may thing you've only got a few rows in your table, and refuse
to use the indices, because it thinks sequential scans are relatively cheap.

Ross
-- 
Ross J. Reedstrom, Ph.D., <reedstrm@rice.edu> 
NSBRI Research Scientist/Programmer
Computer and Information Technology Institute
Rice University, 6100 S. Main St.,  Houston, TX 77005


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