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Redo Log Buffer
"Redo" is record of a change to the database
Redo log entries contain before/after images of changed bytes
- Used in recovery operations
Redo buffer is staging area for Redo Log Files
- Redo stored in online and archived log files
Redo buffer written to disk when:
- Commit is issued
- Buffer use reaches specified threshold
- Checkpoint occurs
Notes:
"Redo" is data captured during an update to the database. It can be used to reapply changes to the database in the event of a failure, for example the loss of a disk device. Redo is kept in online and archived redo log files.
The redo log buffer is a staging area for the redo log files. The buffer is written to disk when a commit is executed, when the redo buffer starts to fill and when a checkpoint operation is initiated.