On 2017/08/01 17:54, Simon Riggs wrote: > On 1 August 2017 at 08:37, Amit Langote <langote_amit...@lab.ntt.co.jp> wrote: >> On 2017/08/01 15:22, Simon Riggs wrote: >>> On 1 August 2017 at 07:16, Amit Langote <langote_amit...@lab.ntt.co.jp> >>> wrote: >>>> In f27a6b15e656 (9.6 & later), we decided to "Mark CHECK constraints >>>> declared NOT VALID valid if created with table." In retrospect, >>>> constraints on foreign tables should have been excluded from consideration >>>> in that commit, because the thinking behind the aforementioned commit >>>> (that the constraint is trivially validated because the newly created >>>> table contains no data) does not equally apply to the foreign tables case. >>>> >>>> Should we do something about that? >>> >>> In what way does it not apply? Do you have a failure case? >> >> Sorry for not mentioning the details. >> >> I was thinking that a foreign table starts containing the data of the >> remote object it points to the moment it's created (unlike local tables >> which contain no data to begin with). If a user is not sure whether a >> particular constraint being created in the same command holds for the >> remote data, they may mark it as NOT VALID and hope that the system treats >> the constraint as such until such a time that they mark it valid by >> running ALTER TABLE VALIDATE CONSTRAINT. Since the planner is the only >> consumer of pg_constraint.convalidated, that means the user expects the >> planner to ignore such a constraint. Since f27a6b15e656, users are no >> longer able to expect so. > > For Foreign Tables, it sounds like an issue. Don't think it exists for > normal tables.
Yes. I was saying in my first email that we should not disregard user's request to mark a constraint NOT VALID if the table in question is a *foreign table*. So, it's OK that commit f27a6b15e656 changed things to ignore NOT VALID if it's in the following command: create table foo (a int, constraint check_a check (a > 0) not valid); But, not OK in the following command: create foreign table ffoo ( a int, constraint check_a check (a > 0) not valid ) server loopback options (table_name 'foo'); Thanks, Amit -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers