isk, such as indexed
        reads, are assumed to be in cache.  The default value can be thought of
        as modeling random access as 40 times slower than sequential, while
        expecting 90% of random reads to be cached.
       </P
><P
>        If you believe a 90% cache rate is an incorrect assumption
        for your workload, you can increase random_page_cost to better
        reflect the true cost of random storage reads. Correspondingly,
        if your data is likely to be completely in cache,