Re: Should we update the random_page_cost default value?
| От | Greg Sabino Mullane |
|---|---|
| Тема | Re: Should we update the random_page_cost default value? |
| Дата | |
| Msg-id | CAKAnmmLa+q=4Hzx6=3V1YwKAGaKn67B9oXZCJ43s2xMVOuoqHA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Should we update the random_page_cost default value? (Robert Treat <rob@xzilla.net>) |
| Ответы |
Re: Should we update the random_page_cost default value?
Re: Should we update the random_page_cost default value? Re: Should we update the random_page_cost default value? |
| Список | pgsql-hackers |
Fascinating thread. As the author of the previous thread Bruce mentioned advocating a lower default rpc, I'm obviously highly invested in this.
On Tue, Oct 7, 2025 at 11:38 AM Robert Treat <rob@xzilla.net> wrote:
One of the interesting things about Tomas' work, if you look at the problem from the other end, is that this exposes a thought-line that I
suspect is almost completely untested "in the field", specifically the idea of *raising* random_page_cost as a means to improve performance.
I've been doing this sort of thing for clients a long time, and I always test both directions when I come across a query that should be faster. For real-world queries, 99% of them have no change or improve with a lowered rpc, and 99% get worse via a raised rpc. So color me unconvinced. Obviously finding some way to emulate these real-world queries would be ideal, but alas, real client data and schemas tends to be well protected. One of the take-away lessons from this thread for me is that the TPC-* benchmarks are far removed from real world queries. (Maybe if we ask an LLM to use an ORM to implement TPC-H? Ha ha ha!)
Cheers,
Greg
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