Horton

Re: [Proposal] Global temporary tables

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

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From: wjzeng <wenjing.zwj@alibaba-inc.com>
To: Prabhat Sahu <prabhat.sahu@enterprisedb.com>
Cc: tushar <tushar.ahuja@enterprisedb.com>, 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: 2020-03-26T03:36:48Z
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3月24日 下午9:34，Prabhat Sahu <prabhat.sahu@enterprisedb.com> 写道：
> 
> Hi Wenjing,
> Please check my findings(on gtt_v20.patch) as below:
> 
> TestCase1: (cache lookup failed on GTT)
> -- Session1:
> postgres=# create global temporary table gtt1(c1 int) on commit delete rows;
> CREATE TABLE
> 
> -- Session2:
> postgres=# drop table gtt1 ;
> DROP TABLE
> 
> -- Session1:
> postgres=# create global temporary table gtt1(c1 int) on commit delete rows;
> ERROR:  cache lookup failed for relation 16384
> 
> TestCase2:
> -- Session1:
> postgres=# create global temporary table gtt (c1 integer) on commit preserve rows;
> CREATE TABLE
> postgres=# insert into gtt values(10);
> INSERT 0 1
> 
> -- Session2:
> postgres=# drop table gtt;
> DROP TABLE
> 
> I hope "session2" should not allow to perform the "DROP" operation on GTT having data.

Sorry, I introduced this bug in my refactoring.
It's been fixed.

Wenjing



> 
> Behavior of GTT in Oracle Database in such scenario: For a completed transaction on GTT with(on_commit_delete_rows='FALSE') with data in a session, we will not be able to DROP from any session, we need to TRUNCATE the data first to DROP the table.
> SQL> drop table gtt;
> drop table gtt
>            *
> ERROR at line 1:
> ORA-14452: attempt to create, alter or drop an index on temporary table already
> in use
> 
> 
> On Tue, Mar 17, 2020 at 9:16 AM 曾文旌(义从) <wenjing.zwj@alibaba-inc.com <mailto:wenjing.zwj@alibaba-inc.com>> wrote:
> 
> 
>> 2020年3月11日 下午3:52，Prabhat Sahu <prabhat.sahu@enterprisedb.com <mailto:prabhat.sahu@enterprisedb.com>> 写道：
>> 
>> On Mon, Mar 9, 2020 at 10:02 PM 曾文旌(义从) <wenjing.zwj@alibaba-inc.com <mailto:wenjing.zwj@alibaba-inc.com>> wrote:
>> 
>> 
>> Fixed in global_temporary_table_v18-pg13.patch.
>> Hi Wenjing,
>> Thanks for the patch. I have verified the previous issues with "gtt_v18_pg13.patch" and those are resolved.
>> Please find below case:
>> 
>> postgres=# create sequence seq;
>> CREATE SEQUENCE
>> 
>> postgres=# CREATE GLOBAL TEMPORARY TABLE gtt1(c1 int PRIMARY KEY) ON COMMIT DELETE ROWS;
>> CREATE TABLE
>> 
>> postgres=# CREATE GLOBAL TEMPORARY TABLE gtt2(c1 int PRIMARY KEY) ON COMMIT PRESERVE ROWS;
>> CREATE TABLE
>> 
>> postgres=# alter table gtt1 add c2 int default nextval('seq');
>> ERROR:  cannot reindex global temporary tables
>> 
>> postgres=# alter table gtt2 add c2 int default nextval('seq');
>> ERROR:  cannot reindex global temporary tables
> reindex GTT is already supported
> 
> Please check global_temporary_table_v20-pg13.patch
> 
> 
> Wenjing
> 
> 
> 
>> 
>> Note: We are getting this error if we have a key column(PK/UNIQUE) in a GTT, and trying to add a column with a default sequence into it.
>> 
>> -- 
>> With Regards,
>> Prabhat Kumar Sahu
>> EnterpriseDB: http://www.enterprisedb.com <http://www.enterprisedb.com/>
> 
> 
> 
> -- 
> With Regards,
> Prabhat Kumar Sahu
> EnterpriseDB: http://www.enterprisedb.com <http://www.enterprisedb.com/>