Re: How to monitor Postgres real memory usage

Hi Justin

Thanks for your update. I collect those logs for your reference.
I also collect this file /etc/sysctl.conf and PG logs on the attachment.
(memory_issue.tar.gz).

when the memory issue occur. The log directory will generate a new log
file.

postgresql-2022-05-27_000000.log. Usually only one file to record log
information.
For example:postgresql-2022-05-27_000000.csv

The log which named with *.log will contain a lot of infomation about
memory detail.

What's the output of these commands?
tail /proc/sys/vm/overcommit_*

[root(at)bl4n3icpms vm]# tail /proc/sys/vm/overcommit_*
==> /proc/sys/vm/overcommit_kbytes <==
0

==> /proc/sys/vm/overcommit_memory <==
2

==> /proc/sys/vm/overcommit_ratio <==
60

tail /proc/sys/vm/nr_*hugepages /proc/cmdline

==> /proc/sys/vm/nr_hugepages <==
0

==> /proc/sys/vm/nr_overcommit_hugepages <==
0

==> /proc/cmdline <==
BOOT_IMAGE=/vmlinuz-3.10.0-957.27.2.el7.x86_64
root=/dev/mapper/rootvg-lv_root ro crashkernel=auto rd.lvm.lv=rootvg/lv_root
rd.lvm.lv=rootvg/lv_swap rhgb quiet LANG=en_US.UTF-8

cat /proc/meminfo

[root(at)bl4n3icpms vm]# cat /proc/meminfo
MemTotal: 16266368 kB
MemFree: 203364 kB
MemAvailable: 7823244 kB
Buffers: 3272 kB
Cached: 12978488 kB
SwapCached: 0 kB
Active: 10456284 kB
Inactive: 5042108 kB
Active(anon): 6008156 kB
Inactive(anon): 1738892 kB
Active(file): 4448128 kB
Inactive(file): 3303216 kB
Unevictable: 11292 kB
Mlocked: 11292 kB
SwapTotal: 2097148 kB
SwapFree: 2097148 kB
Dirty: 20 kB
Writeback: 0 kB
AnonPages: 2527924 kB
Mapped: 4527276 kB
Shmem: 5226728 kB
Slab: 268304 kB
SReclaimable: 206876 kB
SUnreclaim: 61428 kB
KernelStack: 4576 kB
PageTables: 106924 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 11856968 kB
Committed_AS: 10488212 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 37468 kB
VmallocChunk: 34359695100 kB
HardwareCorrupted: 0 kB
AnonHugePages: 124928 kB
CmaTotal: 0 kB
CmaFree: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 143208 kB
DirectMap2M: 6148096 kB
DirectMap1G: 12582912 kB

uname -a

Linux bl4n3icpms.lenovo.com 3.10.0-957.27.2.el7.x86_64 #1 SMP Mon Jul 29
17:46:05 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

[root(at)bl4n3icpms vm]# cat /etc/sysctl.conf
# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
#
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
#
# For more information, see sysctl.conf(5) and sysctl.d(5).
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.conf.all.accept_redirects = 0
# edit for pg database used#
kernel.shmmax=16656777216
kernel.shmall=4066596
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.sem = 250 32000 32 128
kernel.pid_max=131072
vm.overcommit_memory=2
vm.overcommit_ratio=60
vm.swappiness=0
# edit for pg database used#

Justin Pryzby <pryzby(at)telsasoft(dot)com> 于2022年5月27日周五 07:35写道：

> On Fri, May 27, 2022 at 01:39:15AM +0800, 徐志宇徐 wrote:
> > Hi Justin
> >
> > Thanks for you explaination.
> >
> > > > What postgres version ?
> > > > How was it installed ? From souce? From a package ?
> > I am using Postgres 11.1 .It's installed by package.
>
> This is quite old, and missing ~4 years of bugfixes.
>
> What's the output of these commands?
> tail /proc/sys/vm/overcommit_*
> tail /proc/sys/vm/nr_*hugepages /proc/cmdline
> cat /proc/meminfo
> uname -a
>
> --
> Justin
>