Re: Remove Deprecated Exclusive Backup Mode - Mailing list pgsql-hackers

From Laurenz Albe
Subject Re: Remove Deprecated Exclusive Backup Mode
Date
Msg-id 4283f81515659fbf5025163a0649f2974403108a.camel@cybertec.at
Whole thread Raw
In response to Re: Remove Deprecated Exclusive Backup Mode  (Stephen Frost <sfrost@snowman.net>)
Responses Re: Remove Deprecated Exclusive Backup Mode  (Stephen Frost <sfrost@snowman.net>)
List pgsql-hackers
Stephen Frost wrote:
> Yes, it *is* impossible to do safe backups with the existing API.  There
> is an unquestionable race condition where a system restart will cause
> your system to not come back up without you going in and removing the
> backup_label file- and the only way you make that race window small is
> to remove the backup_label file right after you run pg_start_backup and
> copy it, and then PUT IT BACK at the end before you call pg_stop_backup,
> which is insane, but otherwise the 'race window' is the ENTIRE length of
> the backup.

I just have an idea:

What about an option to keep WAL around for the duration of an exclusive backup?

That way PostgreSQL can still restart after a crash.  It will take longer than
expected, but it will work.  But then, perhaps the long recovery time is only
marginally better than having to manually delete the backup_label file...

Yours,
Laurenz Albe



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