Re: [Proposal] Global temporary tables

On Mon, Mar 16, 2020 at 1:30 PM Konstantin Knizhnik <
k(dot)knizhnik(at)postgrespro(dot)ru> wrote:

>
> It seems to be expected behavior: GTT data is private to the session and
> postgres_fdw establish its own session where content of the table is empty.
> But if you insert some data in f_gtt1, then you will be able to select
> this data from it because of connection cache in postgres_fdw.
>

Thanks for the explanation.
I am able to insert and select the value from f_gtt1.

postgres=# insert into f_gtt1 values (1,'gtt_c21');
INSERT 0 1
postgres=# select * from f_gtt1;
c1 | c2
----+---------
1 | gtt_c21
(1 row)

I have one more doubt,
As you told above "GTT data is private to the session and postgres_fdw
establish its own session where content of the table is empty."
Please check the below scenario,
we can select data from the "root GTT" and "foreign GTT partitioned table"
but we are unable to select data from "GTT partitioned table"

postgres=# create global temporary table gtt2 (c1 integer, c2 integer)
partition by range(c1);
CREATE TABLE
postgres=# create global temporary table gtt2_p1 (c1 integer, c2 integer);
CREATE TABLE
postgres=# create foreign table f_gtt2_p1 (c1 integer, c2 integer) server
fdw options (table_name 'gtt2_p1');
CREATE FOREIGN TABLE
postgres=# alter table gtt2 attach partition f_gtt2_p1 for values from
(minvalue) to (10);
ALTER TABLE
postgres=# insert into gtt2 select i,i from generate_series(1,5,2)i;
INSERT 0 3
postgres=# select * from gtt2;
c1 | c2
----+----
1 | 1
3 | 3
5 | 5
(3 rows)

postgres=# select * from gtt2_p1;
c1 | c2
----+----
(0 rows)

postgres=# select * from f_gtt2_p1;
c1 | c2
----+----
1 | 1
3 | 3
5 | 5
(3 rows)

Is this an expected behavior?

--

With Regards,
Prabhat Kumar Sahu
EnterpriseDB: http://www.enterprisedb.com