Re: fdw validation function vs zero catalog id

Tom Lane wrote:
>> "The validator function must take two arguments: one of type text[], which
>> will contain the array of options as stored in the system catalogs, and one
>> of type oid, which will be the OID of the system catalog containing the
>> options, or zero if the context is not known."
>
> Hmm, dunno how I missed that. But anyway ISTM the current code conforms
> to that specification just fine. I think what you're really lobbying

It certainly looks like a bug to me -- while performing CREATE or ALTER on a
SQL/MED object, the catalog must surely be known, and one would expect that
the validator function is passed the actual catalog id. Otherwise there would
be no point for the validator function to accept the catalog id at all.

> for is that we remove the "or zero" escape hatch and insist that the
> backend code do whatever it has to do to supply a correct OID. This
> patch shows that that's not too hard right now, but are there going to
> be future situations where it's harder? What was the motivation for
> including the escape hatch in the first place?
>

The validator is run for the generic options specified to CREATE/ALTER FDW,
SERVER and USER MAPPING (+ possible future SQL/MED objects). In this case the
catalog is always known. Also we can assume that the catalog is known, if a user
runs the validator directly. So yes, AFAICS there is no case for the "or zero".

regards,
Martin