| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | tony(dot)reix(at)atos(dot)net |
| Cc: | "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>, sylvie(dot)empereur-mot(at)atos(dot)net |
| Subject: | Re: Shared Memory: How to use SYSV rather than MMAP ? |
| Date: | 2018-11-20 14:53:11 |
| Message-ID: | CA+TgmoaNnv-rjXSvKsMGobL50NiBOu5N06PUvAX5Cy0GCfj0+w@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Nov 20, 2018 at 8:36 AM REIX, Tony <tony(dot)reix(at)atos(dot)net> wrote:
> We are trying to understand why pgbench on AIX is slower compared to Linux/Power on the same HW/Disks.
>
> So, we have yet no idea about what may be the root cause and what should be changed.
>
> So, changing: dynamic_shared_memory_type = sysv seems to help.
>
> And maybe changing the main shared memory segment could also improve the performance. However, how one can change this?
There's no configuration setting for the main shared memory segment,
but removing #define USE_ANONYMOUS_SHMEM from sysv_shmem.c would
probably do the trick.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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