Re: [Proposal] Global temporary tables
| От | 曾文旌(义从) |
|---|---|
| Тема | Re: [Proposal] Global temporary tables |
| Дата | |
| Msg-id | 79D4ADC6-BE08-410B-AD6B-98840F226769@alibaba-inc.com обсуждение исходный текст |
| Ответ на | Re: [Proposal] Global temporary tables (Prabhat Sahu <prabhat.sahu@enterprisedb.com>) |
| Ответы |
Re: [Proposal] Global temporary tables
|
| Список | pgsql-hackers |
2020年3月16日 下午2:23，Prabhat Sahu <prabhat.sahu@enterprisedb.com> 写道：Hi Wenjing,Please check the below scenario, where the Foreign table on GTT not showing records.postgres=# select * from gtt1;
postgres=# create extension postgres_fdw;
CREATE EXTENSION
postgres=# do $d$
begin
execute $$create server fdw foreign data wrapper postgres_fdw options (host 'localhost',dbname 'postgres',port '$$||current_setting('port')||$$')$$;
end;
$d$;
DO
postgres=# create user mapping for public server fdw;
CREATE USER MAPPING
postgres=# create table lt1 (c1 integer, c2 varchar(50));
CREATE TABLE
postgres=# insert into lt1 values (1,'c21');
INSERT 0 1
postgres=# create foreign table ft1 (c1 integer, c2 varchar(50)) server fdw options (table_name 'lt1');
CREATE FOREIGN TABLE
postgres=# select * from ft1;
c1 | c2
----+-----
1 | c21
(1 row)
postgres=# create global temporary table gtt1 (c1 integer, c2 varchar(50));
CREATE TABLE
postgres=# insert into gtt1 values (1,'gtt_c21');
INSERT 0 1
postgres=# create foreign table f_gtt1 (c1 integer, c2 varchar(50)) server fdw options (table_name 'gtt1');
CREATE FOREIGN TABLE
c1 | c2
----+---------
1 | gtt_c21
(1 row)postgres=# select * from f_gtt1;
c1 | c2
----+----
(0 rows)--
I understand that postgre_fdw works similar to dblink.
postgre_fdw access to the table requires a new connection.
The data in the GTT table is empty in the newly established connection.
Because GTT shares structure but not data between connections.
Try local temp table:
create temporary table ltt1 (c1 integer, c2 varchar(50));
insert into ltt1 values (1,'gtt_c21');
create foreign table f_ltt1 (c1 integer, c2 varchar(50)) server fdw options (table_name 'ltt1');
select * from ltt1;
c1 | c2
----+---------
1 | gtt_c21
(1 row)
select * from l_gtt1;
ERROR: relation "l_gtt1" does not exist
LINE 1: select * from l_gtt1;
Wenjing
With Regards,
Prabhat Kumar Sahu
EnterpriseDB: http://www.enterprisedb.com
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