killed session from OS. How to check rollback progress

[Sharma]

I killed an Oracle session from OS(Unix) using kill -9. Before the session was killed it was showing more than 400,000 blocks in used_blk in V$Transaction.
After the session was killed, I don't see anything in v$transaction (right after that). How can I know if the rollback completed or not?

The table is big, about 250 Million rows in it.

[davey23uk]

if it isn't in v$transaction then the rollback is complete

[Sharma]

I am not sure if I am right, but thought of bringing this to forums attention. I saw a lot of activities going on in the view: v$fast_start_transactions. I know this is related to undo segments.
When I stop seeing changes in this view, the query against the table started running normally.