Re: Timeline ID in backup_label file

On 26 October 2017 at 02:50, Michael Paquier <michael(dot)paquier(at)gmail(dot)com> wrote:
> Hi all,
>
> Lately, in order to extract some information from a backup_label file
> in python I have found myself doing something like the following to
> get a timeline number (feel free to reuse that code, especially the
> regex pattern):
> pattern = re.compile('^START WAL
> LOCATION:.*([0-9A-F]+\/[0-9A-F]+).*\(file ([0-9A-F]+)\)')
> if pattern.match(backup_lable_line):
> current_lsn = m.group(1)
> current_segment = m.group(2)
> current_tli = str(int(current_segment[:8], 16))
>
> That's more or less similar to what read_backup_label()@xlog.c does
> using sscanf(), still I keep wondering why we need to go through this
> much complication to get the origin timeline number of a base backup,
> information which is IMO as important as the start LSN when working on
> backup methods.
>
> I would find interesting to add at the bottom of the backup_label file
> a new field called "START TIMELINE: %d" to put this information in a
> more understandable shape. Any opinions?

Strong "yes" from me.

--
Craig Ringer http://www.2ndQuadrant.com/
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