I got somewhat different: $ ./randcost /usr/local/pgsql/data Collecting sizing information ... Running random access timing test ... Running sequential access timing test ... Running null loop timing test ... random test: 13 sequential test: 15 null timing test: 11
random_page_cost = 0.500000 Chris > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Bruce Momjian > Sent: Tuesday, 10 September 2002 2:02 PM > To: Curt Sampson > Cc: Tom Lane; [EMAIL PROTECTED]; PostgreSQL-development; Ray Ontko > Subject: Re: [HACKERS] 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 > [EMAIL PROTECTED] | (610) 359-1001 > + If your life is a hard drive, | 13 Roberts Road > + Christ can be your backup. | Newtown Square, > Pennsylvania 19073 > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster > ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
