Kbase P19759: How are database changes dealt with during online backup?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
07/12/2006 |
|
Status: Verified
GOAL:
How are database changes dealt with during online backup?
GOAL:
Is it possible for users to continue updating data while the an online backup occurs?
FIX:
At the moment the probkup begins, operations against the database are suspended until the BI file is backed up. This ensures there is a snapshot of the database from when the probkup command was executed.
After the BI file is backed up, the blocks in the database get backed up, from the beginning of the database to the end of the database. The exception to this stage is when an incremental online backup is done, which backs up only the data that has changed since the last full or incremental backup.
Because users can make changes during an online backup, database buffers are written to disk while the online backup is running. If a database block needs to be modified before it gets backed up, the online backup jumps to that block and writes it out so that it can be modified. When the online backup encounters that block again, it simply skips the block, because it has already been backed up.