Horton

Re: [Proposal] Global temporary tables

tushar <tushar.ahuja@enterprisedb.com>

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From: tushar <tushar.ahuja@enterprisedb.com>
To: Prabhat Sahu <prabhat.sahu@enterprisedb.com>, 曾文旌(义从) <wenjing.zwj@alibaba-inc.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: 2020-02-25T13:56:02Z
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.

Hi ,

pg_upgrade  scenario is failing if database is containing  global 
temporary table

=============================
centos@tushar-ldap-docker bin]$ ./psql postgres
psql (13devel)
Type "help" for help.

postgres=# create global temporary table  t(n int);
CREATE TABLE
postgres=# \q
===============================

run pg_upgrade -

[centos@tushar-ldap-docker bin]$ ./pg_upgrade -d /tmp/t1/ -D /tmp/t2 -b 
. -B .
Performing Consistency Checks
-----------------------------
Checking cluster versions    ok
Checking database user is the install user                   ok
Checking database connection settings                       ok
Checking for prepared transactions                             ok
Checking for reg* data types in user tables                 ok
--
--
If pg_upgrade fails after this point, you must re-initdb the
new cluster before continuing.

Performing Upgrade
------------------
Analyzing all rows in the new cluster                        ok
Freezing all rows in the new cluster                          ok
Deleting files from new pg_xact                                ok
--
--
Restoring database schemas in the new cluster
ok
Copying user relation files
   /tmp/t1/base/13585/16384
error while copying relation "public.t": could not open file 
"/tmp/t1/base/13585/16384": No such file or directory
Failure, exiting

regards,

On 2/25/20 7:06 PM, Prabhat Sahu wrote:
> 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 
> <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/>
>

-- 
regards,tushar
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