This is purely learning purpose, that which incomplete recovery type is use in which condition? And DBA is bound to choose one or can choose anyone of following Incomplete recovery type?

  • Scn-based incomplete recovery.
  • Time-based incomplete recovery.
  • Change-based incomplete recovery.
  • Cancel-based incomplete recovery.

I read oracle document and it says There may be a number of different reasons,

  • Recovering a dropped table
  • taking a table to a point-in-time to recover changes made by a user incorrectly.

Is there more reasons ?

  • Recovering to the last known good state (pre-fault) for a system, or to a specific known state (like pre-test) for a system.
    – pmdba
    Aug 6, 2021 at 19:23

1 Answer 1


There really is no difference. Incomplete recovery is, by definition, recovering to some point prior to the last committed change in the online redo logs. It's just a matter of how you specify that point in time. It all ends up being 'scn based'. That is, recovery is up to a specified SCN, whether that SCN is specified directly or indirectly.

If you use "time based" (set until time ....) then that time is, behind the scenes, translated to the last scn before the specified time. "cancel based" will continue to prompt for the next archive redo until you say 'cancel', then complete out the last processed scn .. so when you respond 'cancel' you are really saying "recover to the last scn you processed".

As far as which to use under which condition, you use the one that appears to be the most convenient given the circumstances at the time. Have you looked at the 'Diagnosing and Responding to Failures' section of the Oracle Database Backup and Recovery User's Guide?

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