Re: pg_basebackup ignores the existing data directory permissions

On Fri, Feb 15, 2019 at 10:15 AM Michael Paquier <michael(at)paquier(dot)xyz>
wrote:

> On Thu, Feb 14, 2019 at 11:21:19PM +1100, Haribabu Kommi wrote:
> > On Thu, Feb 14, 2019 at 8:57 PM Magnus Hagander <magnus(at)hagander(dot)net>
> wrote:
> >> I think it could be argued that neither initdb *or* pg_basebackup should
> >> change the permissions on an existing directory, because the admin may
> have
> >> done that intentionally. But when they do create the directory, they
> should
> >> follow the same patterns.
> >
> > Hmm, even if the administrator set some specific permissions to the data
> > directory, PostgreSQL server doesn't allow server to start if the
> > permissions are not (0700) for versions less than 11 and (0700 or
> > 0750) for version 11 or later.
>
> Yes, particularly with pg_basebackup -R this adds an extra step in the
> user flow.
>
> > To let the user to use the PostgreSQL server, user must change the
> > permissions of the data directory. So, I don't see a problem in
> > changing the permissions by these tools.
>
> I certainly agree with the point of Magnus that both tools should
> behave consistently, and I cannot actually imagine why it would be
> useful for an admin to keep a more permissive data folder while all
> the contents already have umasks set at the same level as the primary
> (or what initdb has been told to use), but perhaps I lack imagination.
> If we doubt about potential user impact, the usual, best, answer is to
> let back-branches behave the way they do now, and only do something on
> HEAD.
>

I also agree that both inidb and pg_basebackup should behave same.
Our main concern is that standby data directory that doesn't follow
the primary data directory permissions can lead failures when the standby
gets promoted.

Lack of complaints from the users, how about making this change in the HEAD?

Regards,
Haribabu Kommi
Fujitsu Australia