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Re: [Proposal] Global temporary tables

曾文旌 (义从) <wenjing.zwj@alibaba-inc.com>

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From: 曾文旌(义从) <wenjing.zwj@alibaba-inc.com>
To: Prabhat Sahu <prabhat.sahu@enterprisedb.com>
Cc: "Pavel Stehule" <pavel.stehule@gmail.com>, "Robert Haas" <robertmhaas@gmail.com>, "Tomas Vondra" <tomas.vondra@2ndquadrant.com>, "Konstantin Knizhnik" <k.knizhnik@postgrespro.ru>, "PostgreSQL Hackers" <pgsql-hackers@postgresql.org>, 蔡松露(子嘉) <zijia@taobao.com>, Cai, Le <le.cai@alibaba-inc.com>, 萧少聪(铁庵) <shaocong.xsc@alibaba-inc.com>
Date: 2020-02-27T04:13:07Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. PageAddItemExtended(): Add LP_UNUSED assertion.

  2. Remove temporary files after backend crash

  3. Fix comment in indexing.c

  4. Fix failure to ignore leftover temp tables after a server crash.


> 2020年2月25日 下午9:36，Prabhat Sahu <prabhat.sahu@enterprisedb.com> 写道：
> 
> 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
Fixed in global_temporary_table_v15-pg13.patch


Wenjing


> 
> Thanks,
> Prabhat Sahu
> 
> On Tue, Feb 25, 2020 at 2:25 PM 曾文旌(义从) <wenjing.zwj@alibaba-inc.com <mailto:wenjing.zwj@alibaba-inc.com>> wrote:
> 
> 
>> 2020年2月24日 下午5:44，Prabhat Sahu <prabhat.sahu@enterprisedb.com <mailto: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 <mailto: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 <http://www.enterprisedb.com/>