Horton

Re: [Proposal] Global temporary tables

Prabhat Sahu <prabhat.sahu@enterprisedb.com>

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From: Prabhat Sahu <prabhat.sahu@enterprisedb.com>
To: 曾文旌 <wenjing.zwj@alibaba-inc.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: 2020-03-31T13:59:15Z
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 Wenjing,
Thanks for the new patch.
I saw with the patch(gtt_v23.patch), we are supporting the new concept
"global temporary sequence"(i.e. session-specific sequence), is this
intentional?

postgres=# create *global temporary sequence* gt_seq;
CREATE SEQUENCE
postgres=# create sequence seq;
CREATE SEQUENCE
postgres=# \d+
                              List of relations
 Schema |  Name  |   Type   | Owner | Persistence |    Size    |
Description
--------+--------+----------+-------+-------------+------------+-------------
 *public | gt_seq | sequence | edb   | session     | 8192 bytes |*
 public | seq    | sequence | edb   | permanent   | 8192 bytes |
(2 rows)

postgres=# select *nextval('gt_seq')*, nextval('seq');
 nextval | nextval
---------+---------
      * 1* |       1
(1 row)

postgres=# select nextval('gt_seq'), nextval('seq');
 nextval | nextval
---------+---------
       *2* |       2
(1 row)

-- Exit and re-connect to psql prompt:
postgres=# \q
[edb@localhost bin]$ ./psql postgres
psql (13devel)
Type "help" for help.

postgres=# select nextval('gt_seq'), nextval('seq');
 nextval | nextval
---------+---------
      * 1* |       3
(1 row)

postgres=# select nextval('gt_seq'), nextval('seq');
 nextval | nextval
---------+---------
       *2 *|       4
(1 row)

On Tue, Mar 31, 2020 at 9:46 AM 曾文旌 <wenjing.zwj@alibaba-inc.com> wrote:

>
>
> 2020年3月27日 下午5:21，tushar <tushar.ahuja@enterprisedb.com> 写道：
>
> On 3/27/20 10:55 AM, 曾文旌 wrote:
>
> Hi Wenjing,
> This patch(gtt_v21_pg13.patch) is not applicable on PG HEAD, I hope you
> have prepared the patch on top of some previous commit.
> Could you please rebase the patch which we can apply on HEAD ?
>
> Yes, It looks like the built-in functions are in conflict with new code.
>
>
> This error message looks wrong  to me-
>
> postgres=# reindex table concurrently t ;
> ERROR:  cannot create indexes on global temporary tables using concurrent
> mode
> postgres=#
>
> Better message would be-
>
> ERROR:  cannot reindex global temporary tables concurrently
>
> I found that the local temp table automatically disables concurrency mode.
> so, I made some improvements, The reindex GTT behaves the same as the
> local temp table.
>
>
> Wenjing
>
>
>
>
> --
> regards,tushar
> EnterpriseDB  https://www.enterprisedb.com/
> The Enterprise PostgreSQL Company
>
>
>

-- 

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