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Sybase Transaction Logs Backups

A transaction log backup captures the transaction log which contains a record of all committed or uncommitted transactions. Transaction log backups are consistent with the start time of the backup.

The use of transaction log backups make point-in-time recovery possible. This is useful in the scenario of a database failure where it is unacceptable to lose any data and you want to restore to the point of failure. If you use only full backups, you will be able to restore to the time of the backup, but not to a point-in-time between backups.

A transaction log backup is similar to a traditional incremental backup you might perform on a file system because the transaction log backup contains only the new changes since the full or another transaction log backup.

Each time a transaction log is backed up it is truncated to the exact time of the backup. No checkpoint is issued at this time, therefore dirty pages are not written to disk before or after a transaction log backup. If there are dirty pages, any completed transactions will need to be rolled forward if a transaction log restore is performed. Any transactions that are not completed at the time a transaction log backup is performed are rolled back during a restore involving a transaction log backup.

 

Last modified: 3/1/2018 8:11:48 PM