Copycluster and backup consistency
It's unclear from the documentation at what point a copycluster or backup is consistent.
For a backup, the documentation states "This type of backup provides a consistent image of the database at the time the backup occurred.", but if a backup takes 1.5 hours, is that the start or end of the backup or copycluster ?
In some databases (Oracle) it's at the end, and others (Informix) it's at the start.
Does vbr put a hold on file deletions while it's running in order that all files that are present at the start are still present at the end and are not missed while copycluster'ing or backing up ?
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Answers
The backup process snapshots the catalog at the start of the backup transaction, so that is the point of consistency.
Thanks Bryan, and for the last question, does vbr put a hold on file deletions while it's running in order that all files that are present at the start are still present at the end and are not missed while copycluster'ing or backing up ?
There is transaction isolation during vbr: Internal task "Database Snapshot" holds a catalog lock while backup runs, which would block deletes during backup. Deletes and purges would not commit until after backup in this case.