From: | Matthias Apitz <guru(at)unixarea(dot)de> |
---|---|
To: | pgsql-general(at)lists(dot)postgresql(dot)org |
Subject: | kernel.shmmax and kernel.shmall for Linux server |
Date: | 2021-02-12 10:24:37 |
Message-ID: | YCZXZSwdTAVSxiZB@c720-r368166.fritz.box |
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Lists: | pgsql-general |
Hello,
I've read the doc https://www.postgresql.org/docs/13/kernel-resources.html
but I'm still relatively clueless, what to set. For example for our
standard installations like
- RAM: 32 GByte
- one PostgreSQL 13.1 server
- one database with ~400 tables, 4 GByte in size
- 100-200 connecting PostgreSQL-clients (C/C++ application servers,
single threaded, for interactive usage)
The above document says, the Linux default values are good enough, but
they're:
# /usr/sbin/sysctl kernel | grep shm
kernel.shm_next_id = -1
kernel.shm_rmid_forced = 0
kernel.shmall = 1152921504606846720
kernel.shmmax = 18446744073709551615
kernel.shmmni = 4096
The values are coming from
# cat /boot/sysctl.conf-5.3.18-24.46-default
...
kernel.shmmax = 0xffffffffffffffff
# SHMALL = SHMMAX/PAGE_SIZE*(SHMMNI/16)
kernel.shmall = 0x0fffffffffffff00
Any hints for real values?
matthias
--
Matthias Apitz, ✉ guru(at)unixarea(dot)de, http://www.unixarea.de/ +49-176-38902045
Public GnuPG key: http://www.unixarea.de/key.pub
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