Re: Should we update the random_page_cost default value? - Mailing list pgsql-hackers

From David Rowley
Subject Re: Should we update the random_page_cost default value?
Date
Msg-id CAApHDvpmpT575gSe2JZrKW-yTtQxza8x6FjFWhnpBEhSZUZmSQ@mail.gmail.com
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In response to Re: Should we update the random_page_cost default value?  (Greg Sabino Mullane <htamfids@gmail.com>)
List pgsql-hackers
On Wed, 8 Oct 2025 at 08:15, Greg Sabino Mullane <htamfids@gmail.com> wrote:
> I've been doing this sort of thing for clients a long time, and I always test both directions when I come across a
querythat should be faster. For real-world queries, 99% of them have no change or improve with a lowered rpc, and 99%
getworse via a raised rpc. So color me unconvinced. 

I wonder how much past experience for this on versions before v18
count in now that we have AIO. The bar should have moved quite
significantly with v18 in terms of how often Seq Scans spend waiting
for IO vs Index Scans. So maybe Tomas's results shouldn't be too
surprising. Maybe the graph would look quite different with io_method
= 'sync'.. ?

David



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