Re: PATCH: Configurable file mode mask

On Tue, Mar 20, 2018 at 05:44:22PM -0400, Stephen Frost wrote:
> * David Steele (david(at)pgmasters(dot)net) wrote:
>> On 3/16/18 11:12 AM, Stephen Frost wrote:
>> It seems to me that pg_basebackup and pg_receivexlog should have a -g
>> option to control the mode of the files that they write to disk (not
>> including the modes stored in the tar files).
>>
>> Or perhaps we should just update the perms in the tar files for now and
>> leave the rest alone.
>
> Having options to pg_basebackup to control what's done makes sense to
> me- but whatever those options do, I'd expect them to apply equally to
> the tar files and to the files extracted with plain mode. Having those
> be different really strikes me as very odd.

Agreed for the consistency part, permissions should be applied
consistently for the folder and the tar format.

Having the option for pg_receivewal definitely makes sense to me, as it
is the one in charge of opening and writing the WAL segments. For
pg_basebackup, let's not forget that there is one tar file for each
tablespace, and that each file is received separately using a COPY
stream. There is some logic already which parses the tar header part of
an individual file in order to look for recovery.conf (see
ReceiveTarFile() in pg_basebackup.c). It would be possible to enforce
grouping permissions when receiving each file, and this would be rather
low-cost in performance I think. Honestly, my vote would go for having
the permissions set correctly by the source server as this brings
consistency to the whole experience without complicating the interface
of pg_basebackup, and this also makes the footprint of this patch on
pg_basebackup way lighter.
--
Michael