Redo record called Redo entry - Oracle Redo Log

Discussion

• Nirja Shah   -Posted on 24 Sep 15
  - Redo log files are filled with redo records.
  
  - A redo record, also called a redo entry, is made up of a group of change vectors, each of which is a description of a change made to a single block in the database.
  
  - For example, if you change a salary value in an employee table, you generate a redo record containing change vectors that describe changes to the data segment block for the table, the undo segment data block, and the transaction table of the undo segments.
  
  - Redo entries record data that you can use to reconstruct all changes made to the database, including the undo segments.
  
  - Therefore, the redo log also protects rollback data.
  
  - When you recover the database using redo data, the database reads the change vectors in the redo records and applies the changes to the relevant blocks.

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