paging and google.com question from Kytes new book

From: <rgaffuri_at_cox.net>
Date: Fri, 26 Sep 2003 05:44:41 -0800
Message-ID: <F001.005D12E6.20030926054441@fatcity.com>

Im in the middle of Kytes new tuning book. He states that google uses a query similiar to this to return web pages in their search function:

select /*+ FIRST_ROWS */ b.*
from ( select a.*, a.rownum

      from (your query here) a
      where rownum < <<pick max number of rows you want in a batch >>)

where rownum > <<will start with 1 and be max + 1 for each 'page' >>

If they are using oracle to do this, how do they get the estimated number of total results? Is it from 'cardinality'? Do you know which data dictionary that comes from? explain plan is costly so they cant be using that.

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Author: <rgaffuri_at_cox.net
  INET: rgaffuri_at_cox.net

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