Autocommit inside one SQL command

Question

Hi,
I have 2 tables A and B each have two columns id and name. I used "update A set A.name = (Select B.name from B where A.id=B.id)" to update table A's name. However, when both tables are very large( say 5M rows), Since Oracle will commit only after a command, so, the DB will hold the 5M rows in the rollback segments, if the rollback segments are not large enough, the updating will be very slow. Is there any way to let Oracle commit inside one SQL command? For exemple, auto commit after every 10000 rows get updated.
Thanks.

Answer 1

Thanks for your comments. We have done some tests:
1. We used a flag to limit the number of rows for updating in 2000, 5000, 10000 and 50000 rows. We found that the time/rows in 2000 rows was much lower than in 50000 rows. The higher the testing rows, the higher time/rows was.
2. We used single SQL (update ... select .. from) command to update whole table vs used one select SQL and a seperate update SQL to update table A one record by one record using Java. I thought first one should be much fast than second one. But there were not big diferrence.
Do you have any ideal for tuning this DML?
Thanks.