Amazing with MySQL 5.1.7

[David]

I've posted a question in http://lists.mysql.com/cluster/3237
I have a table with MyISAM store engine and its size is about 340M with
5,000,000 rows
When I convert it to NDBCLUSTER with 5.0.18 store engine, its size becomes
1.4G
With MySQL 5.1.7 beta, its size becomes 259.84M
Huh, much smaller than MySQL 5.0.18
But I confused about it, why its smaller then the original ?
As mentioned in MySQL Reference Manual, it has overheads in MySQL Cluster,so
the size is theoretically bigger than original
My calculation is:
select table_name,engine,round(data_length/1024/1024,2) from
Information_Schema.tables where table_name = 'user1'
+------------+------------+--------------------------------+
| table_name | engine | round(data_length/1024/1024,2) |
+------------+------------+--------------------------------+
| user1 | MyISAM | 332.81 |
| user1 | NDBCLUSTER | 259.84 |
+------------+------------+--------------------------------+




Thanks, :)