Re: Backup strategy using 'wal_keep_segments'

On Tue, Oct 31, 2017 at 9:53 AM, Rhhh Lin <ruanlinehan(at)hotmail(dot)com> wrote:
> I would actually be an advocate for using a proper archive_command in order
> to facilitate a proper (Per the documentation) PITR and backup strategy.

You should avoid using your own fancy archive command. There are
things that WAL-E for this purpose, and even if you do make sure that
the segment data is flushed to disk before sending back 0 as exit code
to the client.

> However, a colleague had suggested such a creative approach (Possibly, less
> administrative overhead, ease of maintenance? I'm not sure) and I struggled
> to find any evidence online in blogs/white-papers/documentation that this
> was a feasible approach. That said, I couldn't find any info rejecting it as
> a method either, which led me to post here. Essentially, this was a
> difference of opinion on approach, and I was looking to gather information
> in order to make an informed opposing argument.

Backup methods should not be fancy, just reliable.

> My only thought now would be how could I decipher, within the sequence chain
> of WAL files, up to which file has the "archival" progressed to. i.e. which
> files are not susceptible to being called upon again for
> restartpoints/checkpoints. That is, where is my absolute point (or file) of
> archival using something along the lines of 'pg_current_xlog_location'.

There is the system view called pg_stat_archiver for that. If you are
using something like pg_receivexlog, pg_stat_replication is the way to
go to monitor the archiving progress.
--
Michael