Redo and Undo

  • Thomas Kyte


This chapter describes two of the most important pieces of data in an Oracle database: redo and undo. Redo is the information Oracle records in online (and archived) redo log files in order to “replay” your transaction in the event of a failure. Undo is the information Oracle records in the undo segments in order to reverse, or roll back, your transaction.


Temporary Table Media Failure Index Block Oracle Database Buffer Cache 

Copyright information

© Thomas Kyte 2014

Authors and Affiliations

  • Thomas Kyte
    • 1
  1. 1.VAUnited States

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