K8SPG-1073: Remove restore_command when backups are disabled

internal/pgbackrest/postgres.go

@@ -82,6 +82,7 @@ func PostgreSQL(
 	if inCluster.CompareVersion("2.9.0") >= 0 {
 		restore = "/opt/crunchy/bin/restore-command-wrapper.sh " + restore
 	}
+	restoreOverridden := false
 	if inCluster.Spec.Patroni != nil && inCluster.Spec.Patroni.DynamicConfiguration != nil {
 		postgresql, ok := inCluster.Spec.Patroni.DynamicConfiguration["postgresql"].(map[string]any)
 		if ok {
@@ -90,11 +91,22 @@ func PostgreSQL(
 				restore_command, ok := params["restore_command"].(string)
 				if ok {
 					restore = restore_command
+					restoreOverridden = true
 				}
 			}
 		}
 	}
-	outParameters.Mandatory.Add("restore_command", restore)
+
+	// If backups are disabled, there is no pgBackRest repository to restore WAL
+	// from. Unlike archive_command, restore_command can't be replaced with a
+	// no-op placeholder: Postgres treats a zero exit status as "the file was
+	// placed", so a placeholder would make it think recovery succeeded when it
+	// didn't. Leave restore_command unset so Postgres relies on streaming
+	// replication and local WAL only -- unless the user explicitly configured
+	// their own restore_command.
+	if backupsEnabled || restoreOverridden {
+		outParameters.Mandatory.Add("restore_command", restore)
+	}
 
 	if inCluster.Spec.Standby != nil && inCluster.Spec.Standby.Enabled && inCluster.Spec.Standby.RepoName != "" {
 

internal/pgbackrest/postgres_test.go

@@ -90,6 +90,59 @@ func TestPostgreSQLParameters(t *testing.T) {
 		})
 	})
 
+	t.Run("backups disabled", func(t *testing.T) {
+		cluster := new(v1beta1.PostgresCluster)
+		parameters := new(postgres.Parameters)
+
+		if cluster.Labels == nil {
+			cluster.Labels = make(map[string]string)
+		}
+		cluster.Labels["pgv2.percona.com/version"] = version.Version()
+
+		// No restore_command override: the key is omitted entirely, since a
+		// pgBackRest command would fail with no repository configured.
+		PostgreSQL(cluster, parameters, false)
+		assert.DeepEqual(t, parameters.Mandatory.AsMap(), map[string]string{
+			"archive_mode":    "on",
+			"archive_command": "true",
+		})
+
+		// An explicit user override is still respected even with backups disabled.
+		dynamic := map[string]any{
+			"postgresql": map[string]any{
+				"parameters": map[string]any{
+					"restore_command": "/bin/true",
+				},
+			},
+		}
+		if cluster.Spec.Patroni == nil {
+			cluster.Spec.Patroni = &v1beta1.PatroniSpec{}
+		}
+		cluster.Spec.Patroni.DynamicConfiguration = dynamic
+
+		PostgreSQL(cluster, parameters, false)
+		assert.DeepEqual(t, parameters.Mandatory.AsMap(), map[string]string{
+			"archive_mode":    "on",
+			"archive_command": "true",
+			"restore_command": "/bin/true",
+		})
+
+		// A standby cluster following an external repo needs restore_command
+		// regardless of this cluster's own backups.enabled setting.
+		cluster.Spec.Standby = &v1beta1.PostgresStandbySpec{
+			Enabled:  true,
+			RepoName: "repo99",
+		}
+		cluster.Spec.Patroni.DynamicConfiguration = nil
+
+		PostgreSQL(cluster, parameters, false)
+		assert.DeepEqual(t, parameters.Mandatory.AsMap(), map[string]string{
+			"archive_mode":    "on",
+			"archive_command": "true",
+			"restore_command": `/opt/crunchy/bin/restore-command-wrapper.sh pgbackrest --stanza=db archive-get %f "%p" --repo=99`,
+		})
+	})
+
 	t.Run("2.8.0< version", func(t *testing.T) {
 		cluster := new(v1beta1.PostgresCluster)
 		parameters := new(postgres.Parameters)