Re: Doc tweak for huge_pages?

On 11/30/17 23:35, Thomas Munro wrote:
> On Fri, Dec 1, 2017 at 5:04 PM, Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
>> On Fri, Dec 01, 2017 at 04:01:24PM +1300, Thomas Munro wrote:
>>> Hi hackers,
>>>
>>> The manual implies that only Linux can use huge pages. That is not
>>> true: FreeBSD, Illumos and probably others support larger page sizes
>>> using transparent page coalescing algorithms. On my FreeBSD box
>>> procstat -v often shows PostgreSQL shared buffers in "S"-flagged
>>> memory. I think we should adjust the manual to make clear that it's
>>> the *explicit request for huge pages* that is supported only on Linux
>>> (and hopefully soon Windows). Am I being too pedantic?
>>
>> I suggest to remove "other" and include Linux in the enumeration, since it also
>> supports "transparent" hugepages.
>
> Hmm. Yeah, it does, but apparently it's not so transparent. So if we
> mention that we'd better indicate in the same paragraph that you
> probably don't actually want to use it. How about the attached?

Part of the confusion is that the huge_pages setting is only for shared
memory, whereas the kernel settings affect all memory. Is the same true
for the proposed Windows patch?

--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services