Re: BUG #4548: Documentation Contradiction for 8.3 - Mailing list pgsql-bugs

In response to "Barry Reddy" <barryreddy@gmail.com>:
>
> The following bug has been logged online:
>
> Bug reference:      4548
> Logged by:          Barry Reddy
> Email address:      barryreddy@gmail.com
> PostgreSQL version: 8.3.3
> Operating system:   Linux 2.6.24-19-server i686 RHEL5
> Description:        Documentation Contradiction for 8.3
> Details:
>
> I’ve been going over the PostgreSQL documentation for pg_archiving,
> And have been struck by an apparent contradiction, which I’m hoping
> To clarify…not sure if you have any thoughts, or can refer this to any
> Contacts for a clarification, if so, feel free to forward.
>
> http://www.postgresql.org/docs/8.3/interactive/backup-file.html
>
> 1.    The database server must be shut down in order to get a usable backup.
> Half-way measures such as disallowing all connections will not work (in part
> because tar and similar tools do not take an atomic snapshot of the state of
> the file system, but also because of internal buffering within the server).
> Information about stopping the server can be found in Section 17.5. Needless
> to say that you also need to shut down the server before restoring the
> data.
>
> http://www.postgresql.org/docs/8.3/interactive/continuous-archiving.html#BAC
> KUP-BASE-BACKUP
>
> 3.    Perform the backup, using any convenient file-system-backup tool such as
> tar or cpio. It is neither necessary nor desirable to stop normal operation
> of the database while you do this.
>
> Can anyone clarify if this apparent contradiction is an oversight ?  Old
> documentation with new archiving documentation patched on, with no attention
> paid to the seeming contradiction on guidelines for filesystem backups of a
> running PG database ?

The data is correct and non-contradictory.  The problem is that you're
reading two different documents on two different methods of making
backups.  The methods have different rules that must be followed to
get a good backup.

--
Bill Moran
Collaborative Fusion Inc.
http://people.collaborativefusion.com/~wmoran/

wmoran@collaborativefusion.com
Phone: 412-422-3463x4023