"Umar Farooq Minhas" <umarfm13(at)hotmail(dot)com> writes:
> How can we accrately estimate the "seq_page_fetch" and =
> "random_page_fetch" costs from outside the postgres using for example a =
> C routine.
Use a test case larger than memory. Repeat many times to average out
noise. IIRC, when I did the experiments that led to the current
random_page_cost of 4.0, it took about a week before I had numbers I
trusted.
regards, tom lane