If the table expression for a derived table contains a LIMIT clause then the estimate of the number of rows read from the derived table may be badly off in mariadb-5.3:

MariaDB [test]> create table t1 (a int);
Query OK, 0 rows affected (0.02 sec)

MariaDB [test]> insert into t1 values
-> (8), (3), (4), (7), (9), (5), (1), (2);
Query OK, 8 rows affected (0.00 sec)
Records: 8 Duplicates: 0 Warnings: 0

MariaDB [test]> select * from (select * from t1 limit 3) t;
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3 rows in set (0.00 sec)

MariaDB [test]> explain select * from (select * from t1 limit 3) t;
------------------------------------------------------------------+

------------------------------------------------------------------+

------------------------------------------------------------------+
2 rows in set (0.00 sec)