Bruce- With the change in the script that I mentioned to you off-list (which I believe just pointed it at our "real world" data), I got the following results with 6 successive runs on each of our two development platforms:
(We're running PGSQL 7.2.1 on Debian Linux 2.4) System 1: 1.2 GHz Athlon Processor, 512MB RAM, Database on IDE hard drive random_page_cost = 0.857143 random_page_cost = 0.809524 random_page_cost = 0.809524 random_page_cost = 0.809524 random_page_cost = 0.857143 random_page_cost = 0.884615 System 2: Dual 1.2Ghz Athlon MP Processors, SMP enabled, 1 GB RAM, Database on Ultra SCSI RAID 5 with Hardware controller. random_page_cost = 0.894737 random_page_cost = 0.842105 random_page_cost = 0.894737 random_page_cost = 0.894737 random_page_cost = 0.842105 random_page_cost = 0.894737 I was surprised that the SCSI RAID drive is generally slower than IDE, but the values are in line with the results that others have been getting. -Nick > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Bruce Momjian > Sent: Monday, September 09, 2002 1:14 AM > To: PostgreSQL-development > Subject: Re: [HACKERS] Script to compute random page cost > > > > OK, turns out that the loop for sequential scan ran fewer times and was > skewing the numbers. I have a new version at: > > ftp://candle.pha.pa.us/pub/postgresql/randcost > > I get _much_ lower numbers now for random_page_cost. ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
