Re: Bitmap scan cost model (was Re: bitmap scans, btree scans, and tid order)

From: "Zeugswetter Andreas DAZ SD" <ZeugswetterA(at)spardat(dot)at>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Jeffrey W(dot) Baker" <jwbaker(at)acm(dot)org>
Cc: <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Bitmap scan cost model (was Re: bitmap scans, btree scans, and tid order)
Date: 2005-05-19 11:56:36
Message-ID: E1539E0ED7043848906A8FF995BDA5790C5170@m0143.s-mxs.net
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> But to get the estimated cost ratio to match up with the actual cost
> ratio, we'd have to raise random_page_cost to nearly 70, which is a bit
> hard to credit. What was the platform being tested here?

Why ? Numbers for modern single disks are 1-2Mb/s 8k random and 50-120 Mb/s
sequential.

Andreas

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