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(义从) <wenjing.zwj@alibaba-inc.com>
Cc: Robert Haas <robertmhaas@gmail.com>, tushar <tushar.ahuja@enterprisedb.com>, Pavel Stehule <pavel.stehule@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: 2020-03-09T12:24:01Z
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 All,

Kindly check the below scenario.

*Case 1: *
postgres=# CREATE GLOBAL TEMPORARY TABLE gtt1(c1 int) on commit delete rows;
CREATE TABLE
postgres=# CREATE GLOBAL TEMPORARY TABLE gtt2(c1 int) on commit preserve
rows;
CREATE TABLE
postgres=# vacuum gtt1;
VACUUM
postgres=# vacuum gtt2;
VACUUM
postgres=# vacuum;
VACUUM
postgres=# \q

*Case 2: Exit and reconnect to psql prompt.*
[edb@localhost bin]$ ./psql  postgres
psql (13devel)
Type "help" for help.

postgres=# vacuum gtt1;
WARNING:  skipping vacuum empty global temp table "gtt1"
VACUUM
postgres=# vacuum gtt2;
WARNING:  skipping vacuum empty global temp table "gtt2"
VACUUM
postgres=# vacuum;
WARNING:  skipping vacuum empty global temp table "gtt1"
WARNING:  skipping vacuum empty global temp table "gtt2"
VACUUM

Although in "Case1" the gtt1/gtt2 are empty, we are not getting "WARNING:
 skipping vacuum empty global temp table" for VACUUM in "Case 1".
whereas we are getting the "WARNING" for VACUUM in "Case2".


On Fri, Mar 6, 2020 at 12:41 PM 曾文旌(义从) <wenjing.zwj@alibaba-inc.com> wrote:

>
>
> > 2020年3月5日 下午10:38，Robert Haas <robertmhaas@gmail.com> 写道：
> >
> > On Thu, Mar 5, 2020 at 9:19 AM tushar <tushar.ahuja@enterprisedb.com>
> wrote:
> >> WARNING:  relfilenode 13589/1663/19063 not exist in gtt shared hash
> when forget
> >> ERROR:  out of shared memory
> >> HINT:  You might need to increase max_active_gtt.
> >>
> >> also , would be great  if we can make this error message  user friendly
> like  - "max connection reached"  rather than memory error
> >
> > That would be nice, but the bigger problem is that the WARNING there
> > looks totally unacceptable. It's looks like it's complaining of some
> > internal issue (i.e. a bug or corruption) and the grammar is poor,
> > too.
>
> Yes, WARNING should not exist.
> This is a bug in the rollback process and I have fixed it in
> global_temporary_table_v17-pg13.patch
>
>
> Wenjing
>
>
> >
> > --
> > Robert Haas
> > EnterpriseDB: http://www.enterprisedb.com
> > The Enterprise PostgreSQL Company
>
>
>
>

-- 

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