random_page_cost - Mailing list pgsql-general

From Barry L. Geipel
Subject random_page_cost
Date
Msg-id 022901c42223$9c752860$8c83a8c0@future
Whole thread Raw
Responses Re: random_page_cost
List pgsql-general
How should the random_page_cost be calculated?

If our disk system does sustained sequential reads at 400MBps, a
sequential page fetch will take 0.02ms.

If the read seek time is 4ms, does this mean that the random_page_cost
is 200 (4/0.02)?

Or should we use the track-to-track seek time of 0.6ms, which would give
a random_page_cost of 30?

Or something else?

Barry Geipel
(barry@GeipelNet.com)



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