Actually set MEMORY_LIMIT_IN_BYTES based on cgroups limits

[jpopelka]

Hi,

in common.sh POSTGRESQL_SHARED_BUFFERS and POSTGRESQL_EFFECTIVE_CACHE_SIZE are calculated based on MEMORY_LIMIT_IN_BYTES (if set).
But I don't see MEMORY_LIMIT_IN_BYTES set anywhere and it doesn't seem to be set automatically in a container with memory limits specified (for example in Openshift/k8s or when you run a container via podman/docker and specify --memory).

FYI: I'm experimenting with memory-related settings because I'm seeing #396 (postgresql-12-centos7) and have no idea what else to try.

[pkubatrh]

Hi thanks for the PR.

We are actually using the cgroups limits, but it might not be immediately obvious. The environment variables are set here: https://github.com/sclorg/postgresql-container/blob/master/src/root/usr/bin/run-postgresql#L6
And the cgroups-limits script is available here: https://github.com/sclorg/s2i-base-container/blob/master/core/root/usr/bin/cgroup-limits

[pkubatrh]

Also @phracek might be able to help with the debugging from the container image/Openshift side, @fila43 from the postgresql side

[jpopelka]

Ok, that's why I haven't found it, thanks. Closing then.