Re: explanation for random_page_cost is outdated

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Тема Re: explanation for random_page_cost is outdated
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Msg-id 729A1432-9FF9-485F-8643-ED0F3D5ECDD6@ya.ru
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Ответ на Re: explanation for random_page_cost is outdated  (Bruce Momjian <bruce@momjian.us>)
Ответы Re: explanation for random_page_cost is outdated  (Bruce Momjian <bruce@momjian.us>)
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Yes, I saw recommendations for 1.1 early, but why? Why such exactly precision number, why 1.1? Is here ever a
theoreticalor experimental prof? 

As for me, random_page_cost depended not only not characteristic of a storage device (hdd or ssd), but also on
assumptionsabout how much of the database is in memory cache (90% by default). And this is a very rough assumption (of
causein ideal whole database must fit in the memory cache). 

And so I don't see any reason to recommend exactly value 1.1, simple 1 is good too, especially for an ideal server with
hugememory cache. 


> 27 апр. 2020 г., в 19:16, Bruce Momjian <bruce@momjian.us> написал(а):
>
> I have been recommending 1.1 as a value for random_page_cost for SSDs
> for years, and I think it would be helpful to suggest that value, so doc
> patch attached.
>
> --
>  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
>  EnterpriseDB                             https://enterprisedb.com
>
> + As you are, so once was I.  As I am, so you will be. +
> +                      Ancient Roman grave inscription +
> <random.diff>




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