From the below link about delayed block cleanout
http://asktom.oracle.com/pls/asktom/f?p=100:11:310568588939032::::P11_QUESTION_ID:275215756923
2. DELAYED BLOCK CLEANOUT:
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This is best illustrated with an example: Consider a transaction that updates a million
row table. This obviously visits a large number of database blocks to make the change to
the data. When the user commits the transaction Oracle does NOT go back and revisit these
blocks to make the change permanent. It is left for the next transaction that visits any
block affected by the update to 'tidy up' the block (hence the term 'delayed block
cleanout').
My question is:
1) If after a user commits the transaction, the database is shutdown so that no new transaction happens. What would happen to the changes? Would it be commited or rolledback?, as no other transactions occur to apply the changes to the datafile.
2) How long would oracle wait for the next transaction to occur to tidy up the block?.
Thanks