Prometheus Postgres Logical Replication Metrics Exporter

Simple prometheus exporter for monitoring PostgreSQL logical replication.

Building and running

$ make build

$ ./bin/export --help
Usage of ./bin/exporter:
  -listen-address string
    	The address to listen on for HTTP requests. (default ":9394")
  -log-level string
    	Level of the logs. (default "info")
  -primary-uri string
    	Connection URI of the primary instance host.
  -standby-uri string
    	Connection URI of the standby instance host.

Postgres role setup

Both roles (on primary and standby instances) require superuser priveleges as they access system tables and functions, such as pg_stat_subscription, pg_stat_replication, pg_replication_slots tables and pg_current_wal_lsn() function.

Available metrics

Metric	Type	Description
pg_logical_replication_subscription_status	Guage	Status of subscription.
pg_logical_replication_subscription_lag_bytes	Guage	The amount of WAL records generated in the primary, but not yet applied in the standby.
pg_logical_replication_publication_status	Guage	Status of publication.
pg_logical_replication_publication_lag	Guage	The amount of WAL records generated in the primary, but not yet sent to the standby.
pg_logical_replication_replication_slot_status	Guage	Status of replication slot.

Local development

This repo contains a compose file which facilitates local setup of postgres primary and standby instance. To run instances you will need either docker, podman-compose or nerdctl. To run compose execute following commands:

$ make start-db

To load seed data to databases run following command:

$ make seed-db

To stop database instances run:

$ make stop-db

To run the exporter locally using these databases run:

$ ./bin/exporter --primary-uri="postgres://primary:primary@localhost:9432/primary?sslmode=disable" --standby-uri="postgres://standby:standby@localhost:9442/standby?sslmode=disable"