On Mar 13, 2023, at 11:10 AM, Joe Conway <m...@joeconway.com> wrote: > > On 3/13/23 14:50, Israel Brewster wrote: >> Looks like V2: >> root@novarupta:~# stat -fc %T /sys/fs/cgroup/ >> cgroup2fs > > Interesting -- it does indeed look like you are using cgroup v2 > > So the file you want to look at in that case is: > 8<----------- > cat > /sys/fs/cgroup/system.slice/system-postgresql.slice/postgresql@14.service/memory.max > 4294967296 > > cat > /sys/fs/cgroup/system.slice/system-postgresql.slice/postgresql@14.service/memory.high > 3221225472 > 8<----------- > If the value comes back as "max" it means no limit is set.
This does, in fact, appear to be the case here: root@novarupta:~# cat /sys/fs/cgroup/system.slice/system-postgresql.slice/postgresql@13-main.service/memory.max max root@novarupta:~# cat /sys/fs/cgroup/system.slice/system-postgresql.slice/postgresql@13-main.service/memory.high max root@novarupta:~# which would presumably indicate that it’s a system level limit being exceeded, rather than a postgresql specific one? The syslog specifically says "Memory cgroup out of memory”, if that means something (this is my first exposure to cgroups, if you couldn’t tell). --- Israel Brewster Software Engineer Alaska Volcano Observatory Geophysical Institute - UAF 2156 Koyukuk Drive Fairbanks AK 99775-7320 Work: 907-474-5172 cell: 907-328-9145 > > In this example (on my Linux Mint machine with a custom systemd unit file) I > have memory.max set to 4G and memory.high set to 3G. > > The value of memory.max determines when the OOM killer will strike. The value > of memory.high will determine when the kernel goes into aggressive memory > reclaim (trying to avoid memory.max and thus an OOM kill). > > The corresponding/relevant systemd unit file parameters are: > 8<----------- > MemoryAccounting=yes > MemoryHigh=3G > MemoryMax=4G > 8<----------- > > There are other ways that memory.max may get set, but it seems most likely > that the systemd unit file is doing it (if it is in fact set). > > -- > Joe Conway > PostgreSQL Contributors Team > RDS Open Source Databases > Amazon Web Services: https://aws.amazon.com >
