Re: BUG #8043: 9.2.4 doesn't open WAL files from archive, only looks in pg_xlog

On Apr 6, 2013, at 2:24 AM, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com> wrote:

> Incidentally, I bumped into another custom backup script just a few weeks back that also excluded backup_label. I don't know what the author was thinking when he wrote that, but it seems to be a surprisingly common mistake. Maybe it's the "label" in the filename that makes people think it's not important. Perhaps we should improve the documentation to make it more explicit that backup_label must be included in the backup. The docs already say that, though, so I suspect that people making this mistake have not read the docs very carefully anyway.
>
> Perhaps a comment in the beginning of backup_label would help:
>
> # NOTE: This file MUST be included in the backup. Otherwise, the backup
> # is inconsistent, and restoring it may result in a corrupt database.
>
> Jeff B., assuming that you excluded backup_label from the backup for some reason, do you have any thoughts on what would've helped you to avoid that mistake? Would a comment like above have helped - did you look inside backup_label at any point?

I think such a comment could be helpful. The base backups did contain backup_label. That is how another script would determine what WAL files to remove. It looked at the oldest base backup's backup_label file to get the oldest WAL file to keep.

My problem was that backup_label was excluded from the data directory when it was sync'd from the base backup. (We keep base backups separate from data directories, so they can be reused.) I guess it was excluded because it was assumed to not be used by archive recovery. So, clarifying backup_label's importance there seems helpful.

Thank you for your help,
- Jeff
--
Jeff Bohmer | Corporate Technology Manager | VisionLink, Inc.
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