Re: Script to compute random page cost

OK, I have a better version at:
ftp://candle.pha.pa.us/pub/postgresql/randcost

I have added a null loop which does a dd on a single file without
reading any data, and by netting that loop out of the total computation
and increasing the number of tests, I have gotten the following results
for three runs:random test:       36sequential test:   33null timing test:  27random_page_cost = 1.500000
random test:       38sequential test:   32null timing test:  27random_page_cost = 2.200000
random test:       40sequential test:   31null timing test:  27random_page_cost = 3.250000

Interesting that random time is increasing, while the others were
stable.  I think this may have to do with other system activity at the
time of the test.  I will run it some more tomorrow but clearly we are
seeing reasonable numbers now.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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