RE: Shared Memory: How to use SYSV rather than MMAP ?

Hi Thomas,

Thanks for the patch !

I've started to work with it. It is now compiling.

Hummmm I have an issue here:

# cd /home2/freeware/src/packages/BUILD/postgresql-11.1/64bit/doc/src/sgml
# gmake
/opt/freeware/bin/xmllint --path . --noout --valid postgres.sgml
/opt/freeware/bin/xsltproc --path . --stringparam pg.version '11.1' stylesheet.xsl postgres.sgml
Makefile:135: recipe for target 'html-stamp' failed
gmake: *** [html-stamp] Segmentation fault (core dumped)

That reaches an issue in /opt/freeware/bin/xsltproc , on AIX.
I never had this I think.

That seems to have nothing to do with your patch, however. Investigating.

I'm trying to work-around this.

I'll let you know.

About testing it, I guess that I'll have to add:

huge_pages = on

in the postgresql.conf file. Correct ?

Thanks !

Cordialement,

Tony Reix

tony(dot)reix(at)atos(dot)net

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________________________________
De : Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>
Envoyé : vendredi 1 février 2019 14:49:01
À : REIX, Tony
Cc : Andres Freund; Robert Haas; Pg Hackers; EMPEREUR-MOT, SYLVIE
Objet : Re: Shared Memory: How to use SYSV rather than MMAP ?

Bonjour Tony,

On Sat, Jan 5, 2019 at 3:35 AM REIX, Tony <tony(dot)reix(at)atos(dot)net> wrote:
> Thanks for the 2 patches!
>
> I've seen also the discussion around this subject. Very interesting. Should I wait for a decision been taken? or should I study and experiment your patches before?

I am planning to commit the 0001 patch shortly, unless there are
objections. I attach a new version, which improves the documentation
a bit (cross-referencing the new GUC and the section on sysctl
settings). That will give us shared_memory_type = sysv.

Can you please try out the 0002 patch on AIX and see if it works, and
if not, tell us how to fix it? :-) The desired behaviour is:

1. If huge_pages = off, it doesn't use them.
2. ff huge_pages = try, it tries to use them, but if it can't
(perhaps because the Unix user doesn't have CAP_BYPASS_RAC_VMM
capability), it should fall back to non-huge page.
3. If huge_pages = on, it tries to use them, but if it can't it fails
to start up.

There may also be a case for supporting different page sizes
explicitly (huge_pages = 16GB?), but that could be done later.

--
Thomas Munro
https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.enterprisedb.com&amp;data=02%7C01%7Ctony.reix%40atos.net%7C1c903b29b1f04b1f7ae208d6884c2a9a%7C33440fc6b7c7412cbb730e70b0198d5a%7C0%7C0%7C636846258044522047&amp;sdata=GsmfQPlv5hvfesT7gZpthSY5hDc7j5Lp4HsPy6VP9k8%3D&amp;reserved=0

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