Tom Lane wrote:
> Yeah, I'm drifting towards the position that we should just define the
> defaults as being whatever they are locally, rather than trying to be
> cute about supporting remotely-executed defaults. It looks to me like
> if we try to do the latter, we're going to have pitfalls and weird
> corner cases that will never be quite transparent. There's also the
> argument that this'd be a lot of work that benefits only some FDWs,
> since the whole concept of remote column defaults doesn't apply when
> the FDW's data source isn't a traditional RDBMS.
That was my first thought on the topic, to have a solution that
is simple (if not perfect).
Your argument that it would be unpleasant to lose the ability
to use sequence-generated remote default values made me reconsider.
But there is a workaround, namely to use a trigger before insert
to generate an automatic primary key (e.g. if the inserted value is
NULL).
Maybe it would be good to add a few hints at workarounds like that
to the documentation if it's going to be local defaults.
Yours,
Laurenz Albe