feat: add transaction ID age to postgres_exporter

[valigula]

What kind of change does this PR introduce?

feature INDATA-1261

What is the current behavior?

What is the new behavior?

Add pg_wraparound custom metric to postgres_exporter that tracks the maximum transaction ID age across all databases. This enables proactive monitoring of wraparound risk before it reaches critical thresholds.

• New queries.yml with max(age(datfrozenxid)) query
• Deployed to /opt/postgres_exporter/ via Ansible

Additional context

Test

Copying/creating the file in local-dev, setting the permissions

root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# touch /tmp/queries.yml
root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# vi /tmp/queries.yml
root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# cp /tmp/queries.yml /opt/postgres_exporter/queries.yml
root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# chown root:root /opt/postgres_exporter/queries.yml
root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# chmod 0644 /opt/postgres_exporter/queries.yml
root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# ls -la /opt/postgres_exporter/queries.yml
-rw-r--r-- 1 root root 265 Aug 21 15:29 /opt/postgres_exporter/queries.yml

restarting postgres_exported

root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter#  systemctl restart postgres_exporter
root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# journalctl -u postgres_exporter -n 30 --no-pager
Aug 21 10:20:52 db-hkcvznjogvigukdmrznn postgres_exporter[620]: ts=2026-08-21T10:20:52.593Z caller=postgres_exporter.go:682 level=error err="Error opening connection to database (host=localhost%20dbname=postgres%20sslmode=disable%20user=supabase_admin%20pg_stat_statements.track=none%20application_name=postgres_exporter): driver: bad connection"
Aug 21 10:21:47 db-hkcvznjogvigukdmrznn postgres_exporter[620]: ts=2026-08-21T10:21:47.635Z caller=server.go:74 level=info msg="Established new database connection" fingerprint=localhost:5432
Aug 21 10:21:47 db-hkcvznjogvigukdmrznn postgres_exporter[620]: ts=2026-08-21T10:21:47.640Z caller=postgres_exporter.go:613 level=info msg="Semantic version changed" server=localhost:5432 from=0.0.0 to=17.6.0
Aug 21 15:21:00 db-hkcvznjogvigukdmrznn systemd[1]: Stopping postgres_exporter.service - Postgres Exporter...
Aug 21 15:21:00 db-hkcvznjogvigukdmrznn systemd[1]: postgres_exporter.service: Deactivated successfully.
Aug 21 15:21:00 db-hkcvznjogvigukdmrznn systemd[1]: Stopped postgres_exporter.service - Postgres Exporter.
Aug 21 15:21:00 db-hkcvznjogvigukdmrznn systemd[1]: postgres_exporter.service: Consumed 1.771s CPU time, 21.4M memory peak, 0B memory swap peak.
-- Boot 1fa8a6e85faf4f039d299003f54d504a --
Aug 21 15:21:14 db-hkcvznjogvigukdmrznn systemd[1]: Started postgres_exporter.service - Postgres Exporter.
Aug 21 15:21:15 db-hkcvznjogvigukdmrznn postgres_exporter[630]: ts=2026-08-21T15:21:15.228Z caller=main.go:86 level=warn msg="Error loading config" err="Error opening config file \"postgres_exporter.yml\": open postgres_exporter.yml: no such file or directory"
Aug 21 15:21:15 db-hkcvznjogvigukdmrznn postgres_exporter[630]: ts=2026-08-21T15:21:15.231Z caller=proc.go:267 msg="Excluded databases" databases=[]
Aug 21 15:21:15 db-hkcvznjogvigukdmrznn postgres_exporter[630]: ts=2026-08-21T15:21:15.231Z caller=main.go:99 level=warn msg="The extended queries.yaml config is DEPRECATED" file=/opt/postgres_exporter/queries.yml
Aug 21 15:21:15 db-hkcvznjogvigukdmrznn postgres_exporter[630]: ts=2026-08-21T15:21:15.236Z caller=tls_config.go:274 level=info msg="Listening on" address=[::]:9187
Aug 21 15:21:15 db-hkcvznjogvigukdmrznn postgres_exporter[630]: ts=2026-08-21T15:21:15.237Z caller=tls_config.go:277 level=info msg="TLS is disabled." http2=false address=[::]:9187
Aug 21 15:21:17 db-hkcvznjogvigukdmrznn postgres_exporter[630]: ts=2026-08-21T15:21:17.518Z caller=server.go:74 level=info msg="Established new database connection" fingerprint=localhost:5432
Aug 21 15:21:17 db-hkcvznjogvigukdmrznn postgres_exporter[630]: ts=2026-08-21T15:21:17.531Z caller=postgres_exporter.go:613 level=info msg="Semantic version changed" server=localhost:5432 from=0.0.0 to=17.6.0
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn systemd[1]: Stopping postgres_exporter.service - Postgres Exporter...
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn systemd[1]: postgres_exporter.service: Deactivated successfully.
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn systemd[1]: Stopped postgres_exporter.service - Postgres Exporter.
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn systemd[1]: Started postgres_exporter.service - Postgres Exporter.
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn postgres_exporter[3208]: ts=2026-08-21T15:29:33.120Z caller=main.go:86 level=warn msg="Error loading config" err="Error opening config file \"postgres_exporter.yml\": open postgres_exporter.yml: no such file or directory"
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn postgres_exporter[3208]: ts=2026-08-21T15:29:33.120Z caller=proc.go:267 msg="Excluded databases" databases=[]
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn postgres_exporter[3208]: ts=2026-08-21T15:29:33.120Z caller=main.go:99 level=warn msg="The extended queries.yaml config is DEPRECATED" file=/opt/postgres_exporter/queries.yml
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn postgres_exporter[3208]: ts=2026-08-21T15:29:33.121Z caller=tls_config.go:274 level=info msg="Listening on" address=[::]:9187
Aug 21 15:29:33 db-hkcvznjogvigukdmrznn postgres_exporter[3208]: ts=2026-08-21T15:29:33.121Z caller=tls_config.go:277 level=info msg="TLS is disabled." http2=false address=[::]:9187

Asserting the results

root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# curl -s http://localhost:9187/metrics | grep -i wraparound
# HELP pg_wraparound_max_transaction_id_age Max transaction ID age (in XIDs; wraparound risk) across databases
# TYPE pg_wraparound_max_transaction_id_age gauge
pg_wraparound_max_transaction_id_age{server="localhost:5432"} 1137
root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# psql -U supabase_admin -d postgres -c "SELECT max(age(datfrozenxid)) AS max_transaction_id_age FROM pg_database;"
Password for user supabase_admin:
root@db-hkcvznjogvigukdmrznn:/opt/postgres_exporter# psql  -h localhost -U supabase_admin -d postgres -c "SELECT max(age(datfrozenxid)) AS max_transaction_id_age FROM pg_database;"
 max_transaction_id_age
------------------------
                   1137
(1 row)

[Copilot]

Pull request overview

Adds a custom postgres_exporter metric to monitor wraparound risk by exporting the maximum age(datfrozenxid) across all databases, deployed via Ansible.

Changes:

• Deploy a new queries.yml containing the pg_wraparound custom query/metric definition.
• Copy queries.yml into /opt/postgres_exporter/ during exporter provisioning.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
ansible/tasks/internal/postgres-exporter.yml	Copies the new custom queries.yml into the exporter install directory during provisioning.
ansible/files/queries.yml	Defines the pg_wraparound extended query exporting max transaction ID age across databases.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.