Re: Different memory allocation strategy in Postgres 11? - Mailing list pgsql-general

From Thomas Munro
Subject Re: Different memory allocation strategy in Postgres 11?
Date
Msg-id CAEepm=0dQdoZTLVZ0cEA0aXUxdvpNx8iKRrtigZ8V9amvpZcvw@mail.gmail.com
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In response to Re: Different memory allocation strategy in Postgres 11?  (Thomas Kellerer <spam_eater@gmx.net>)
Responses Re: Different memory allocation strategy in Postgres 11?  (Thomas Kellerer <spam_eater@gmx.net>)
List pgsql-general
On Sat, Oct 27, 2018 at 6:10 AM Thomas Kellerer <spam_eater@gmx.net> wrote:
> Jeff Janes schrieb am 26.10.2018 um 17:42:
> >     I typically configure "shared_buffers = 4096MB" on my 16GB system as sometimes when testing, it pays off to
havea bigger cache.
 
> >
> >     With Postgres 10 and earlier, the Postgres process(es) would only allocate that memory from the operating
systemwhen needed.
 
> >     So right after startup, it would only consume several hundred MB, not the entire 4GB
> >
> >     However with Postgres 11 I noticed that it immediately grabs the complete memory configured for shared_buffers
duringstartup.
 
> >
> >     It's not really a big deal, but I wonder if that is an intentional change or a result from something else?
> >
> >
> > Do you have pg_prewarm in shared_preload_libraries?
>
> No. The only shared libraries are those for pg_stat_statemens

Does your user have "Lock Pages in Memory" privilege?  One thing that
is new in 11 is huge AKA large page support, and the default is
huge_pages=try.  Not a Windows person myself but I believe that should
succeed if you have that privilege and enough contiguous chunks of
physical memory are available.  If you set huge_pages=off does it
revert to the old behaviour?

-- 
Thomas Munro
http://www.enterprisedb.com


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