Re: pg_basebackup, walreceiver and wal_sender_timeout

On Mon, Jan 28, 2019, at 10:25, Michael Paquier wrote:
> On Mon, Jan 28, 2019 at 09:05:26AM +0100, Magnus Hagander wrote:

> > And for plain format, we'd do the same -- sync after each file segment, and
> > then a final one of the directory when done, right?
>
> Well, the code is doing a double amount of work in its current shape
> as we call fsync_pgdata() for the plain format, which cascades to
> pg_wal and all its files, so it seems to me that there is little point
> in issuing a sync when each segment is finished streaming if that's
> what you mean.

Agreed.

While reading the doc page for the pg_basebackup, I've been confused by the fact that it says WAL files will be written to .tarballs (either base.tar or pg_wal.tar) when pg_basebackup is instructed to stream WALs alongside the backup itself. I think it makes sense to elaborate that it only happens when tar format is specified (doc patch is attached).

Cheers,
Oleksii