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: 36
sequential test: 33
null timing test: 27

random_page_cost = 1.500000

random test: 38
sequential test: 32
null timing test: 27

random_page_cost = 2.200000

random test: 40
sequential test: 31
null timing test: 27

random_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
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