Rollback question

We have a situation where we are doing a insert into table1 as select * from table2. The size of table1 when created added with its index size is about 600M. When doing the insert it is generating almost 1.4gigs of rollback space. I thought that inserts were the least rollback intensive, so why is it taking so much rollback space.

Any insights would be appreciated.

Thanks,
Abhijit Received on Mon May 05 1997 - 00:00:00 CDT