Allow page backups from standby

Artur Zakirov · Artur Zakirov · commit 515150cff15c · 2017-03-22T11:50:29.000+03:00
diff --git a/backup.c b/backup.c
@@ -437,10 +437,6 @@ do_backup(bool smooth_checkpoint)
 	if (pg_is_standby() && !from_replica)
 		elog(ERROR, "backup is not allowed for standby");
 
-	/* Page backup is not allowed for replica instance */
-	if (from_replica && current.backup_mode == BACKUP_MODE_DIFF_PAGE)
-		elog(ERROR, "page backup is not allowed for standby");
-
 	/* show configuration actually used */
 	elog(LOG, "========================================");
 	elog(LOG, "backup start");
diff --git a/doc/pg_probackup.md b/doc/pg_probackup.md
@@ -291,7 +291,7 @@ This mode should be used with caution as it allows to delete WAL files required
 
 ### Backup from Standby
 
-If replication is in use, starting with PostgreSQL 9.6 a backup can be taken not only from primary server, but also from standby. Backup taken from standby is absolutely interchangeable with backup taken from primary (bearing in mind possible replication delay). Page-level incremental backups are not allowed to perform from standby.
+If replication is in use, starting with PostgreSQL 9.6 a backup can be taken not only from primary server, but also from standby. Backup taken from standby is absolutely interchangeable with backup taken from primary (bearing in mind possible replication delay).
 
 Currently it is required for primary database server to have `full_page_writes` turned `on` (in future this requirement may be relaxed in the case checksums are enabled on data pages).
 
