Re: pg_basebackup, manifests and backends older than ~12

Greetings,

* David Steele (david@pgmasters.net) wrote:
> On 4/10/20 4:09 AM, Michael Paquier wrote:
> >I have noticed that attempting to use pg_basebackup from HEAD leads to
> >failures when using it with backend versions from 12 and older:
> >$ pg_basebackup -D hoge
> >pg_basebackup: error: backup manifests are not supported by server
> >version 12beta2
> >pg_basebackup: removing data directory "hoge"
> >
> >This is a bit backwards with what we did in the past to maintain
> >compatibility silently when possible, for example look at the handling
> >of temporary replication slots.  Instead of an error when means to
> >force users to have to specify --no-manifest in this case, shouldn't
> >we silently disable the generation of the backup manifest?  We know
> >that this option won't work on older server versions anyway.
> 
> I'm a bit conflicted here. I see where you are coming from, but given that
> writing a manifest is now the default I'm not sure silently skipping it is
> ideal.

It's only the default in v13..  Surely when we connect to a v12 or
earlier system we should just keep working and accept that we don't get
a manifest as part of that.

Thanks,

Stephen