How to do rollback in mysql cluster

[Jeff]

I thought mysql cluster supports rollback. However, It does not seem to be working:

mysql> show create table t \G
*************************** 1. row ***************************
Table: t
Create Table: CREATE TABLE `t` (
`a` int(11) default NULL
) ENGINE=ndbcluster DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

mysql> insert into t2 values (1);
Query OK, 1 row affected (0.01 sec)

mysql> rollback;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from t2;
+------+
| a |
+------+
| 1 |
+------+
1 row in set (0.05 sec)


mysql> show engines;
+------------+---------+----------------------------------------------------------------+
| Engine | Support | Comment |
+------------+---------+----------------------------------------------------------------+
| MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables |
| HEAP | YES | Alias for MEMORY |
| MERGE | YES | Collection of identical MyISAM tables |
| MRG_MYISAM | YES | Alias for MERGE |
| ISAM | NO | Obsolete storage engine, now replaced by MyISAM |
| MRG_ISAM | NO | Obsolete storage engine, now replaced by MERGE |
| InnoDB | YES | Supports transactions, row-level locking, and foreign keys |
| INNOBASE | YES | Alias for INNODB |
| BDB | YES | Supports transactions and page-level locking |
| BERKELEYDB | YES | Alias for BDB |
| NDBCLUSTER | YES | Clustered, fault-tolerant, memory-based tables |
| NDB | YES | Alias for NDBCLUSTER |
| EXAMPLE | YES | Example storage engine |
| ARCHIVE | NO | Archive storage engine |
| CSV | YES | CSV storage engine |
| FEDERATED | YES | Federated MySQL storage engine |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) |
+------------+---------+----------------------------------------------------------------+
18 rows in set (0.00 sec)

Any idea why I can't rollback before commiting?