Re: [Proposal] Global temporary tables

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(at)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(dot)zwj(at)alibaba-inc(dot)com> wrote:

>
>
> > 2020年3月5日 下午10:38，Robert Haas <robertmhaas(at)gmail(dot)com> 写道：
> >
> > On Thu, Mar 5, 2020 at 9:19 AM tushar <tushar(dot)ahuja(at)enterprisedb(dot)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