Re: On-line backup and point-in-time recovery (PITR)

Enzo D'addario wrote:
> Hi All,
>
> I have a couple of questions regarding On-line backup and point-in-time
> recovery (PITR) in the postgres documentation:
>
> 1.How is it that we can create a tar file of the PG Data directory
> whilst postgres is running?

Whe pg_xlog archived files contain information to recover any
inconsistency in the backup tar file.

> 2.What happens with any DB inserts, updates, deletes etc that occur
> between the SELECT pg_start_backup() and the end of the tar?
> They would be already logged in the WAL files and already applied in the
> tarball, do they then get duplicated during log replay in the recover
> process?

No, the recovery is just like crash recovery and everything comes back
clean, but you do have to recover to a time _after_ the end of the
backup. If you want to recover to a time during the backup you have to
use the previous backup and xlog files.

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