Question:

I would like a clear explanation as follows:

In the redo log file there are record all changes made to data. (but not
data block).
In the rollback segments there are the data block both committed and not
committed.

When I use a database in archivelog mode..... Oracle records the redo log
and then archive them
in a destination (log_archive_dest).

But if in the redo log file there aren't a data block, how is possible
Oracle restore
my database in a exactly point in time without the data block?

Answer:

Rollback is also written to redolog.
 

Hth,

Sybrand Bakker, Oracle DBA