BUG #15092: pg_basebackup directory checking

On Mon, Feb 26, 2018 at 03:45:42PM +0000, PG Bug reporting form wrote:

I want to take regular backups on the standby machine using pg_basebackup.

Using pg_basebackup on the non-master machine fails when using tablespaces
and the tablespace directory already exists on the secondary machine.

pg_basebackup: directory "/db/ts1" exists but is not empty

When saving a base backup on the same server as the one where the server
from which the backup is taken, you need to use --tablespace-mapping to
ensure that the tablespace of the backed up instance does not interfere
with the origin. You could as well use the tar format and untar things
after relinking properly things in pg_tblspc in the created data
folder.
--
Michael