Re: Another oddity in handling of WCO constraints in postgres_fdw

(2017/11/01 11:16), Robert Haas wrote:
> On Wed, Oct 4, 2017 at 5:58 PM, Ashutosh Bapat
> <ashutosh.bapat@enterprisedb.com>  wrote:
>> The view with WCO is local but the modification which violates WCO is
>> being made on remote server by a trigger on remote table. Trying to
>> control that doesn't seem to be a good idea, just like we can't
>> control what rows get inserted on the foreign server when they violate
>> local constraints.
>
> I think that's a fair point.

For local constraints on foreign tables, it's the user's responsibility 
to ensure that those constraints matches the remote side, so we don't 
need to ensure those constraints locally.  But I'm not sure if the same 
thing applies to WCOs on views defined on foreign tables, because in 
some case it's not possible to impose constraints on the remote side 
that match those WCOs, as I explained before.

Best regards,
Etsuro Fujita