memory usage: use of 100% of available RAM

[francescor]

What did you do?

We have a postgres-exporter as a service in a Docker Swarm stack

What did you expect to see?

We do not expect container to always reach 100% of RAM in few days

What did you see instead? Under which circumstances?

With prometheus query

(container_memory_working_set_bytes{image!="", container_label_com_docker_swarm_service_name="opencity-aspsr_postgres-exporter"} / (container_spec_memory_limit_bytes{image!=""} > 0) * 100)

we see a steady upwards slope in memory usage: postgres-exporter is gradually consuming all memory over time.

Environment

We have a Docker Swarm service with image:
quay.io/prometheuscommunity/postgres-exporter:v0.17.1

• postgres_exporter version:

  v0.17.1

• postgres_exporter flags:

none

• PostgreSQL version:

  image: 'postgres:14.17-alpine'

[SuperQ]

Can post this with container_memory_rss? Working set is a misleading metric as it includes cache.

[francescor]

Ok, I repeat here the same query above

while here I replace container_memory_working_set_bytes with container_memory_rss

[sysadmind]

I think this might be a good time to add pprof like we did in the elasticsearch_exporter to help us uncover what is using the memory. What do you think @SuperQ? I'll see if I can get around to testing it but should be a very easy change.