Re: foregin table insert error

On 12/14/2014 08:49 AM, Ed Rahn wrote:
> On 12/14/2014 09:30 AM, Adrian Klaver wrote:
>> On 12/14/2014 01:13 AM, Ed Rahn wrote:
>>> Hi,
>>> I have a foreign table that I'm getting an insert error on:
>>>
>>> horsedata=# insert into remote_cache (entry_id, name_id) values(2,1);
>>> ERROR:  null value in column "id" violates not-null constraint
>>> DETAIL:  Failing row contains (null, 1, 2, null).
>>> CONTEXT:  Remote SQL command: INSERT INTO public.cache(id, name_id,
>>> entry_id, value) VALUES ($1, $2, $3, $4)
>>>
>>>
>>> Here is the remote table client side:
>>> horsedata=# \d remote_cache
>>>       Foreign table "public.remote_cache"
>>>    Column  |  Type   | Modifiers | FDW Options
>>> ----------+---------+-----------+-------------
>>>   id       | integer |           |
>>>   name_id  | integer |           |
>>>   entry_id | integer |           |
>>>   value    | integer |           |
>>> Server: home
>>> FDW Options: (table_name 'cache')
>>>
>>>
>>> And here's cache server side:
>>> horsedata=# \d cache;
>>>                                 Table "public.cache"
>>>    Column  |       Type       | Modifiers
>>> ----------+------------------+----------------------------------------------------
>>>
>>>
>>>   id       | integer          | not null default
>>> nextval('cache_id_seq'::regclass)
>>>   name_id  | integer          |
>>>   entry_id | integer          |
>>>   value    | double precision |
>>> Indexes:
>>>      "cache_pkey" PRIMARY KEY, btree (id)
>>>      "cache_name_id_entry_id_key" UNIQUE CONSTRAINT, btree (name_id,
>>> entry_id)
>>>      "ix_cache_entry_id" btree (entry_id)
>>>      "ix_cache_name_id" btree (name_id)
>>>
>>>
>>> Any suggestions?
>>
>> Yes, see here:
>>
>> http://www.postgresql.org/message-id/CA+mi_8bfkaFPNPPx6_W_T_0J9OEMSfXQKCDZo=OMJpWWcCKtoA@mail.gmail.com
>>
>>
> I tried something similar using -1 as well as the above:
> On server I set:
> create function inc_id_cache() returns trigger as $inc$
> begin
> if NEW.id = NULL then
>      NEW.id := nextval('cache_id_seq');
> end if;
> return NEW;
> end;
> $inc$ language plpgsql;
>
> create trigger inc before insert on cache for each row execute procedure
> inc_id_cache();
>
>
> Now in both cases I get:
> horsedata=# insert into remote_cache(name_id, entry_id) values (1, 8);
> ERROR:  null value in column "id" violates not-null constraint
> DETAIL:  Failing row contains (null, 1, 8, null).
> CONTEXT:  Remote SQL command: INSERT INTO public.cache(id, name_id,
> entry_id, value) VALUES ($1, $2, $3, $4)

Just realized that deals with remote side, but not with getting the 
value back to the local side. That stirred a memory which led me to this 
blog post:

http://michael.otacoo.com/postgresql-2/global-sequences-with-postgres_fdw-and-postgres-core/

FYI if I follow correctly this:

=# CREATE FOREIGN TABLE foreign_seq_table (a bigint)
-# SERVER postgres_server OPTIONS (table_name 'seq_table')

should be:

=# CREATE FOREIGN TABLE foreign_seq_table (a bigint)
-# SERVER postgres_server OPTIONS (table_name 'seq_view')
>
> thanks
> Ed
>
>


-- 
Adrian Klaver
adrian.klaver@aklaver.com