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)
359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square,
Pennsylvania19073
