Re: Perplexing, regular decline in performance
Hugh Ranalli <[email protected]>
| Newsgroups | gmane.comp.db.postgresql.performance |
|---|---|
| Message-ID | <CAAhbUMOhmTFUdLHn3TZA9Gh8ijrCVRWmtd0QAkcYKj_kY_5jiQ@mail.gmail.com> |
On Wed, 26 Jun 2019 at 15:18, Tom Lane <[email protected]> wrote: > Alvaro Herrera <[email protected]> writes: > > On 2019-Jun-26, Hugh Ranalli wrote: > >> From my research in preparing for the upgrade, I understood transparent > >> huge pages were a good thing, and should be enabled. Is this not > correct? > > > It is not. > > Yeah ... they would be a good thing perhaps if the quality of the kernel > implementation were better. But there are way too many nasty corner > cases, at least with the kernel versions people around here have > experimented with. You're best off to disable THP and instead manually > arrange for Postgres' shared memory to use huge pages. I forget where > to look for docs about doing that, but I think we have some. > We've been dealing with some other production issues, so my apologies for not replying sooner. I'm seeing now that I have confused huge pages with *transparent* huge pages. We have a maintenance window coming up this weekend, so we'll disable transparent huge pages and configure huge pages manually. I found the docs here: https://www.postgresql.org/docs/11/kernel-resources.html#LINUX-HUGE-PAGES Thank you very much!