Re: Parallel copy

On Tue, Sep 1, 2020 at 3:39 PM Greg Nancarrow <gregn4422@gmail.com> wrote:
>
> Hi Vignesh,
>
> >Can you share with me the script you used to generate the data & the ddl of the table, so that it will help me check
that>scenario you faced the >problem.
 
>
> Unfortunately I can't directly share it (considered company IP),
> though having said that it's only doing something that is relatively
> simple and unremarkable, so I'd expect it to be much like what you are
> currently doing. I can describe it in general.
>
> The table being used contains 100 columns (as I pointed out earlier),
> with the first column of "bigserial" type, and the others of different
> types like "character varying(255)", "numeric", "date" and "time
> without timezone". There's about 60 of the "character varying(255)"
> overall, with the other types interspersed.
>

Thanks Greg for executing & sharing the results.
I tried with a similar test case that you suggested, I was not able to
reproduce the degradation scenario.
If it is possible, can you run perf for the scenario with 1 worker &
non parallel mode & share the perf results, we will be able to find
out which of the functions is consuming more time by doing a
comparison of the perf reports.
Steps for running perf:
1) get the postgres pid
2) perf record -a -g -p <above pid>
3) Run copy command
4) Execute "perf report -g" once copy finishes.

Regards,
Vignesh
EnterpriseDB: http://www.enterprisedb.com