| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Simon Riggs <simon(dot)riggs(at)enterprisedb(dot)com>, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, Jakub Wartak <jakub(dot)wartak(at)enterprisedb(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Damage control for planner's get_actual_variable_endpoint() runaway |
| Date: | 2022-11-21 15:35:46 |
| Message-ID: | CA+TgmobRCDP68aXisje=Ygnh=2wf61Se8DBK+ywjC8rWapLVog@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Mon, Nov 21, 2022 at 10:32 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> > Is there any reason to tie this into page costs? I'd be more inclined
> > to just make it a hard limit on the number of pages. I think that
> > would be more predictable and less prone to surprising (bad) behavior.
>
> Agreed, a simple limit of N pages fetched seems appropriate.
>
> > And to be honest I would be inclined to make it quite a small number.
> > Perhaps 5 or 10. Is there a good argument for going any higher?
>
> Sure: people are not complaining until it gets into the thousands.
> And you have to remember that the entire mechanism exists only
> because of user complaints about inaccurate estimates. We shouldn't
> be too eager to resurrect that problem.
>
> I'd be happy with a limit of 100 pages.
OK.
--
Robert Haas
EDB: http://www.enterprisedb.com
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Robert Haas | 2022-11-21 15:45:53 | Re: allowing for control over SET ROLE |
| Previous Message | Robert Haas | 2022-11-21 15:35:16 | Re: perform_spin_delay() vs wait events |