diff --git a/src/backup.c b/src/backup.c
index 132ad228..6acbda70 100644
--- a/src/backup.c
+++ b/src/backup.c
@@ -3554,8 +3554,8 @@ get_index_list(PGresult *res_db, int db_number,
 
 		res = pgut_execute(db_conn, "SELECT cls.oid, cls.relname "
 									"FROM pg_index idx "
-									"JOIN pg_class cls ON cls.oid=idx.indexrelid "
-									"JOIN pg_am am ON am.oid=cls.relam "
+									"JOIN pg_class cls ON idx.indexrelid=cls.oid "
+									"JOIN pg_am am ON cls.relam=am.oid "
 									"WHERE am.amname='btree' AND cls.relpersistence != 't'",
 									0, NULL);
 	}
@@ -3564,11 +3564,13 @@ get_index_list(PGresult *res_db, int db_number,
 
 		res = pgut_execute(db_conn, "SELECT cls.oid, cls.relname "
 									"FROM pg_index idx "
-									"JOIN pg_class cls ON cls.oid=idx.indexrelid "
-									"JOIN pg_am am ON am.oid=cls.relam "
-									"JOIN pg_tablespace tbl ON tbl.oid=cls.reltablespace "
-									"WHERE am.amname='btree' AND cls.relpersistence != 't' "
-									"AND tbl.spcname != 'pg_global'",0, NULL);
+									"JOIN pg_class cls ON idx.indexrelid=cls.oid "
+									"JOIN pg_am am ON cls.relam=am.oid "
+									"LEFT JOIN pg_tablespace tbl "
+									"ON cls.reltablespace=tbl.oid "
+									"AND tbl.spcname <> 'pg_global' "
+									"WHERE am.amname='btree' AND cls.relpersistence != 't'",
+									0, NULL);
 	}
 
 	/* add info needed to check indexes into index_list */
diff --git a/src/pg_probackup.c b/src/pg_probackup.c
index a1e9652e..dc40fe1c 100644
--- a/src/pg_probackup.c
+++ b/src/pg_probackup.c
@@ -480,9 +480,14 @@ main(int argc, char *argv[])
 		instance_config.pgdata == NULL)
 			elog(ERROR, "required parameter not specified: --instance");
 
-	if (backup_subcmd == CHECKDB_CMD
-	&& (instance_config.logger.log_level_file != LOG_OFF)
-	&& (instance_config.logger.log_directory == NULL))
+	/* Usually checkdb for file logging requires log_directory
+	 * to be specified explicitly, but if backup_dir and instance name are provided,
+	 * checkdb can use the tusual default values or values from config
+	 */
+	if (backup_subcmd == CHECKDB_CMD &&
+		(instance_config.logger.log_level_file != LOG_OFF &&
+		 instance_config.logger.log_directory == NULL) &&
+		(!instance_config.pgdata || !instance_name))
 		elog(ERROR, "Cannot save checkdb logs to a file. "
 			"You must specify --log-directory option when running checkdb with "
 			"--log-level-file option enabled.");