file_per_table and ibdata file

[Nishant Deshpande]

I have file_per_table set, and i see all my tables having their own files as expected.

But, the ibdata file keeps growing... which is exactly what i don't want.

after re-RTFMing, i came across this line
(http://dev.mysql.com/doc/refman/5.1/en/multiple-tablespaces.html)

"""
InnoDB always needs the shared tablespace because it puts its internal data dictionary and undo logs there. The .ibd files are not sufficient for InnoDB to operate.
"""

Am i right in thinking that if i have a big table.. say 100GB, and i do a "insert into foo select * from bigtable", this will effectively force a pretty huge undo log into the ibdata file? and now i have no way of recovering this space (apart from doing a mysqldump and load which in my case will take a *long* time..)

i want to load in big files, but i don't want the ibdata file to take up 20% of my disk (which would be the 'high water mark' of the size of the data i may be loading in).

any comments on if the above is correct and any solutions would be much appreciated.