human readable?redo log,roll back segment,archive

1.are data in redo log file, archive logs,undo tbs ,rollback segment are human readable?

2. what happens to the data within rollback segment,undo tbs after some period of time ?will they be permanetly deleted? or are included in archive logfile?for point in time recovery?

3. does archive log include DDL? if not then what will happen if we delete all data from tbl1 on monday, set unique constraint on the table on tuesday and on wednesday try to do incomplete recovery to mondays date ( there used to be some duplicate entry in tbl1 on monday).

thanks

1) no (unless you use log miner)
2) removed when they arent needed

Quote:

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Originally Posted by davey23uk

2) removed when they arent needed

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in this case then when we do incomplete recovery to bring database up to the point before it failed. where do we get the actual data from?

thanks


when i say human readable I mean whether possible to view data within it directly or using any other tool like log miner and undrestand it.

just figured out answer for
Q2 : rollback segment is only for read consistency and the data is not really required for roll forward. archive logs seems to contain sql (update/delte) and at the time of recovery it just applies it to the DB.