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List:       sqlite-users
Subject:    Re: [sqlite] query performance comparison with access
From:       John Stanton <johns () viacognis ! com>
Date:       2008-10-29 17:27:57
Message-ID: 49089D1D.5080607 () viacognis ! com
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On a large table it will be much faster to use an index than to force a 
row scan as your initial query did.

L B wrote:
> I have obtained a great performance improvement now
> just adding an index in the 2 columns 
> 
> dtfrom and idcatalogue,
> 
> removing the 2 single indexes on the column dtfrom and
> idcatalogue.
> 
> I could not believe, now the query 
> 
> SELECT MAX(DTFROM) AS MAXDT, IDCATALOGUE FROM
> CRONOCATALOGUES GROUP BY IDCATALOGUE
> 
> takes only 2 seconds in sqlite and 5 seconds in
> access.
> May be the field idcatalogue has not to be found in
> the table anymore because it is in the index (this is
> my explanation, but I'm not sure).
> Could not imagine such an improvement!
> 
> Sorry for my ignorance.
> 
> 
>       
> 
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