Re: pg_basebackup, manifests and backends older than ~12

On Mon, Apr 13, 2020 at 11:52:51AM +0900, Kyotaro Horiguchi wrote:
> Since I'm not sure about the work flow that contains taking a
> basebackup from a server of a different version, I'm not sure which is
> better between silently disabling and erroring out.  However, it seems
> to me, the option for replication slot is a choice of the way the tool
> works which doesn't affect the result itself, but that for backup
> manifest is about what the resulting backup contains. Therefore I
> think it is better that pg_basebackup in PG13 should error out if the
> source server doesn't support backup manifest but --no-manifest is not
> specfied, and show how to accomplish their wants (, though I don't see
> the wants clearly).

Not sure what Robert and other authors of the feature think about
that.  What I am rather afraid of is somebody deciding to patch a
script aimed at working across multiple backend versions to add
unconditionally --no-manifest all the time, even for v13.  That would
kill the purpose of encouraging the use of manifests.

> By the way, if I specified --manifest-checksums, it complains about
> incompatible options with a message that would look strange to the
> user.
>
> pg_basebackup: error: --no-manifest and --manifest-checksums are incompatible options
>
> ("I didn't specified such an option..")

How did you trigger that?  I am able to only see this failure when
using --manifest-checksums and --no-manifest together.
--
Michael