K8SPG-1073: Remove restore_command when backups are disabled

[yoav-katz]

CHANGE DESCRIPTION

Problem:
When spec.backups.enabled: false is set, the operator still configures Patroni's restore_command to invoke pgBackRest (pgbackrest --stanza=<name> archive-get %f "%p"), even though no backup repository exists. Any time a replica needs a WAL segment it can't get via streaming replication, Postgres calls this command, which fails because there's no valid stanza/repo — instead of falling back cleanly to "no WAL available from archive."

Cause:
internal/pgbackrest/postgres.go's PostgreSQL() function already neutralizes archive_command when backups are disabled (sets it to a no-op true), but the equivalent handling was missing for restore_command — it was built and added to the Patroni mandatory parameter set unconditionally, with no backupsEnabled check at all.

Solution:
restore_command is no longer set when backups are disabled. Unlike archive_command, it can't simply be pointed at a no-op placeholder like true: Postgres treats a zero exit status from restore_command as "the file was placed at %p," so a placeholder that always succeeds would make Postgres believe WAL recovery succeeded when it didn't, risking a crash or silent gap. Instead, restore_command is omitted entirely in this case, so Postgres relies purely on streaming replication and local WAL. An explicit user override of restore_command via spec.patroni.dynamicConfiguration is still respected regardless of backups.enabled, since that reflects an intentional choice by the user.

CHECKLIST

Jira

• Is the Jira ticket created and referenced properly?
• Does the Jira ticket have the proper statuses for documentation (Needs Doc) and QA (Needs QA)?
• Does the Jira ticket link to the proper milestone (Fix Version field)?

Tests

• Is an E2E test/test case added for the new feature/change?
• Are unit tests added where appropriate?

Config/Logging/Testability

• Are all needed new/changed options added to default YAML files?
• Are all needed new/changed options added to the Helm Chart?
• Did we add proper logging messages for operator actions?
• Did we ensure compatibility with the previous version or cluster upgrade process?
• Does the change support oldest and newest supported PG version?
• Does the change support oldest and newest supported Kubernetes version?

[Copilot]

Pull request overview

This PR updates pgBackRest-related PostgreSQL parameter generation so Patroni does not configure restore_command when backups are disabled, preventing Postgres from attempting (and failing) WAL archive restores when no repository exists.

Changes:

• Omit restore_command from Patroni mandatory parameters when backups are disabled, unless the user explicitly overrides it.
• Add unit test coverage for the “backups disabled” behavior, including override and standby-repo scenarios.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
internal/pgbackrest/postgres.go	Conditionally adds restore_command only when backups are enabled or user-overridden (standby repo still forces it).
internal/pgbackrest/postgres_test.go	Adds a test case ensuring restore_command is omitted when backups are disabled, while preserving override and standby behavior.

[JNKPercona]

Test Name	Result	Time
backup-enable-disable	passed	00:18:06
builtin-extensions	passed	00:08:31
cert-manager-tls	passed	00:09:51
custom-envs	passed	00:24:15
custom-tls	passed	00:07:30
database-init-sql	passed	00:02:54
demand-backup	passed	00:28:03
demand-backup-offline-snapshot	failure	00:10:40
dynamic-configuration	passed	00:03:22
finalizers	passed	00:03:38
init-deploy	passed	00:03:35
huge-pages	passed	00:03:09
major-upgrade-14-to-15	passed	00:11:22
major-upgrade-15-to-16	passed	00:10:30
major-upgrade-16-to-17	passed	00:11:34
major-upgrade-17-to-18	passed	00:09:33
ldap	passed	00:05:56
ldap-tls	passed	00:07:37
monitoring	passed	00:08:31
monitoring-pmm3	passed	00:09:15
one-pod	passed	00:05:57
operator-self-healing	passed	00:10:53
pitr	passed	00:12:32
scaling	passed	00:06:01
scheduled-backup	failure	00:27:02
self-healing	passed	00:09:56
sidecars	passed	00:02:20
standby-pgbackrest	passed	00:17:52
standby-streaming	passed	00:13:19
start-from-backup	passed	00:14:08
tablespaces	passed	00:07:06
telemetry-transfer	passed	00:04:27
upgrade-consistency	passed	00:06:29
upgrade-minor	passed	00:07:39
users	passed	00:04:45

Summary	Value
Tests Run	35/35
Job Duration	02:39:14
Total Test Time	05:48:36

commit: 7387777
image: perconalab/percona-postgresql-operator:PR-1673-7387777b1