abou the cost estimation

Hello, All
I have read the source code /cvsroot/pgsql/src/backend/optimizer/path/costsize.c and there is a function cost_sort(...). I think the code in 464 to 465 lines must be changed to:
startup_cost += npageaccesses *
(1.0 + cost_nonsequential_access(1)) * 0.5;

The original code is:
startup_cost += npageaccesses *
(1.0 + cost_nonsequential_access(npages)) * 0.5;
Can any one discuss about this issue with me ? Thanks for your response very much!
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Guo long jiang. 2002-9-6

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