Checkpoint related columns in PG 17 have been moved from pg_stat_bgwriter to pg_stat_checkpointer

[n-rodriguez]

Fix #1060

See:

• https://www.dbi-services.com/blog/postgresql-17-new-catalog-view-pg_stat_checkpointer/
• https://www.postgresql.org/docs/16/monitoring-stats.html#MONITORING-PG-STAT-BGWRITER-VIEW
• https://www.postgresql.org/docs/17/monitoring-stats.html#MONITORING-PG-STAT-BGWRITER-VIEW

Thank you!

[n-rodriguez]

Hi there! Any news?

[n-rodriguez]

Ping @sysadmind

[BupycHuk]

@SuperQ @wrouesnel @sysadmind, could you please reiew this PR, it's important for PG17 monitoring.

[michael-todorovic]

Hello,
I was interested in this PR as we start to get some PG17. However, we moved to multi-target pattern and we're encountering some issues with PG<17. Here's what I did:

I start a very simple PG16:

docker run --rm -p 5416:5432 -e POSTGRES_PASSWORD=postgres postgres:16 -d postgres

I have a config.yml so the exporter can remotely connect to PG:

auth_modules:
  monitoring:
    type: userpass
    userpass:
      username: postgres
      password: postgres

I start the exporter (with the merged PR):

./postgres_exporter --config.file=config.yml --collector.stat_checkpointer

and I call the exporter:

curl 'http://localhost:9187/probe?auth_module=monitoring&target=localhost:5416/postgres?sslmode=disable'

The exporter outputs this error:

time=2024-11-27T14:32:02.679+01:00 level=ERROR source=collector.go:201 msg="collector failed" target="localhost:5416/postgres?sslmode=disable" name=stat_checkpointer duration_seconds=0.013500983 err="pq: relation \"pg_stat_checkpointer\" does not exist"

I'll try to check how to improve the current PR so it can work in this mode 😄

[n-rodriguez]

ping @sysadmind @wrouesnel @SuperQ

[sysadmind]

I think the code is good and should be good to merge as soon as the Copyright dates are updated.

[michael-todorovic]

👋 @n-rodriguez , would you please check the changes in n-rodriguez#1?
In multi-target mode, the current MR is preventing the exporter to work so I provided some fixes for it :)