Re: Add system identifier to backup manifest

On Mon, Feb 19, 2024 at 12:06:19PM +0530, Amul Sul wrote:
> Agreed, now they will have an error as _could not read file "<DataDir>": Is
> a directory_. But, IIUC, that what usually happens with the dev version, and
> the extension needs to be updated for compatibility with the newer version for
> the same reason.

I was reading through the remaining pieces of the patch set, and are
you sure that there is a need for 0002 at all?  The only reason why
get_dir_controlfile() is introduced is to be able to get the contents
of a control file with a full path to it, and not a data folder.  Now,
if I look closely, with 0002~0004 applied, the only two callers of
get_controlfile() are pg_combinebackup.c and pg_verifybackup.c.  Both
of them have an access to the backup directories, which point to the
root of the data folder.  pg_combinebackup can continue to use
backup_dirs[i].  pg_verifybackup has an access to the backup directory
in the context data, if I'm reading this right, so you could just use
that in verify_system_identifier().

access to the root directory.

I have dropped the 0002 patch -- I don't have a very strong opinion to refactor
get_controlfile() apart from saying that it might be good to have both versions :) .