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From Sylvain Lebresne <sylv...@yakaz.com>
Subject Re: Bad read performances: 'few rows of many columns' vs 'many rows of few columns'
Date Tue, 09 Mar 2010 20:28:26 GMT
> A row causes a disk seek while columns are contiguous.  So if the row isn't
> in the cache, you're being impaired by the seeks.  In general, fatter rows
> should be more performant than skinny ones.

Sure, I understand that. Still, I get 400 columns by seconds (ie, 400 seeks by
seconds) when the rows only have one column by row, while I have 10 columns
by seconds when the row have 100 columns, even though I read only the first
column.

--
Sylvain

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