Re: [Proposal] Global temporary tables - Mailing list pgsql-hackers

Hi All,

Please check the below findings on GTT.
-- Scenario 1:
Under "information_schema", We are not allowed to create "temporary table", whereas we can CREATE/DROP "Global Temporary Table", is it expected ?

postgres=# create temporary table information_schema.temp1(c1 int);
ERROR:  cannot create temporary relation in non-temporary schema
LINE 1: create temporary table information_schema.temp1(c1 int);
                               ^

postgres=# create global temporary table information_schema.temp1(c1 int);
CREATE TABLE

postgres=# drop table information_schema.temp1 ;
DROP TABLE

-- Scenario 2:
Here I am getting the same error message in both the below cases.
We may add a "global" keyword with GTT related error message.

postgres=# create global temporary table gtt1 (c1 int unique);
CREATE TABLE
postgres=# create temporary table tmp1 (c1 int unique);
CREATE TABLE

postgres=# create temporary table tmp2 (c1 int references gtt1(c1) );
ERROR:  constraints on temporary tables may reference only temporary tables

postgres=# create global temporary table gtt2 (c1 int references tmp1(c1) );
ERROR:  constraints on temporary tables may reference only temporary tables

Thanks,

Prabhat Sahu

On Tue, Feb 25, 2020 at 2:25 PM 曾文旌(义从) <wenjing.zwj@alibaba-inc.com> wrote:

2020年2月24日 下午5:44，Prabhat Sahu <prabhat.sahu@enterprisedb.com> 写道：

On Fri, Feb 21, 2020 at 9:10 PM 曾文旌(义从) <wenjing.zwj@alibaba-inc.com> wrote:

Hi,
I have started testing the "Global temporary table" feature,

That's great, I see hope.
from "gtt_v11-pg13.patch". Below is my findings:

-- session 1:
postgres=# create global temporary table gtt1(a int);
CREATE TABLE

-- seeeion 2:
postgres=# truncate gtt1 ;
ERROR:  could not open file "base/13585/t3_16384": No such file or directory

is it expected?

Oh ,this is a bug, I fixed it.

Thanks for the patch.

I have verified the same, Now the issue is resolved with v12 patch.

Kindly confirm the below scenario:

postgres=# create global temporary table gtt1 (c1 int unique);
CREATE TABLE

postgres=# create global temporary table gtt2 (c1 int references gtt1(c1) );
ERROR:  referenced relation "gtt1" is not a global temp table

postgres=# create table tab2 (c1 int references gtt1(c1) );
ERROR:  referenced relation "gtt1" is not a global temp table

Thanks,

Prabhat Sahu

GTT supports foreign key constraints in global_temporary_table_v13-pg13.patch

Wenjing

--

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