> 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