Re: inherit support for foreign tables

On 2015/03/23 2:57, Tom Lane wrote:
> Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp> writes:
>> [ fdw-inh-8.patch ]
>
> I've committed this with some substantial rearrangements, notably:
>
> * I thought that if we were doing this at all, we should go all the way
> and allow foreign tables to be both inheritance parents and children.

I found that when setting a foreign table to be the parent of an
inheritance set that only contains foreign tables, SELECT FOR UPDATE on
the inheritance parent fails with a can't-happen error condition.  Here
is an example:

$ createdb mydb
$ psql mydb
psql (9.5devel)
Type "help" for help.

mydb=# create table t1 (c1 int);
CREATE TABLE
mydb=# create table t2 (c1 int);
CREATE TABLE

$ psql postgres
psql (9.5devel)
Type "help" for help.

postgres=# create extension postgres_fdw;
CREATE EXTENSION
postgres=# create server myserver foreign data wrapper postgres_fdw
options (dbname 'mydb');
CREATE SERVER
postgres=# create user mapping for current_user server myserver;
CREATE USER MAPPING
postgres=# create foreign table ft1 (c1 int) server myserver options
(table_name 't1');
CREATE FOREIGN TABLE
postgres=# create foreign table ft2 (c1 int) server myserver options
(table_name 't2');
CREATE FOREIGN TABLE
postgres=# alter foreign table ft2 inherit ft1;
ALTER FOREIGN TABLE
postgres=# select * from ft1 for update;
ERROR:  could not find junk tableoid1 column

I think this is a bug.  Attached is a patch fixing this issue.

Best regards,
Etsuro Fujita