Re: Logical replication CPU-bound with TRUNCATE/DROP/CREATE many tables

On Thu, Oct 8, 2020 at 2:05 PM Keisuke Kuroda
<keisuke(dot)kuroda(dot)3862(at)gmail(dot)com> wrote:
>
> Hi Dilip,
>
> > I could not see this issue even without the patch, it is taking less
> > than 1s even without the patch. See below results
> >
> > 2020-10-08 13:00:49 BEGIN 509
> > 2020-10-08 13:00:49 table nsp_001.part_0001: INSERT:...
> > 2020-10-08 13:00:49 COMMIT 509 (at 2020-10-08 13:00:48.741986+05:30)
> >
> > Am I missing something?
>
> Thanks for running the tests.
> It is the TRUNCATE decoding that takes time.
> INSERT decoding is fast, even before the patch is applied.
>
> 2020-10-02 14:55:48 BEGIN 508
> 2020-10-02 14:55:48 table nsp_001.part_0001: INSERT ...
> 2020-10-02 14:55:49 COMMIT 508 (at 2020-10-02 14:55:48.744019+09)
>
> However, TRUNCATE decode is slow
> and take 222s in my environment.
>
> 2020-10-02 14:55:50 BEGIN 509
> 2020-10-02 14:59:42 table nsp_001.tbl_001 ... ns p_001.part_1000:
> TRUNCATE: (no-flags)
> 2020-10-02 14:59:42 COMMIT 509 (at 2020-10-02 14:55:50.349219+09)
>
> This script will wait 10 seconds after INSERT exits
> before executing TRUNCATE, please wait for it to run.
>
> When TRUNCATE completes,
> the walsender process should be at 100% CPU.

Okay, thanks for the info, I will run again and see this.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com