Horton

Re: Parallel copy

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: "Hou, Zhijie" <houzj.fnst@cn.fujitsu.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-12-26T15:48:13Z
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. Allow WaitLatch() to be used without a latch.

  2. Add %P to log_line_prefix for parallel group leader

  3. Include replication origins in SQL functions for commit timestamp

  4. Avoid useless buffer allocations during binary COPY FROM.

On Wed, Dec 23, 2020 at 3:05 PM Hou, Zhijie <houzj.fnst@cn.fujitsu.com> wrote:
>
> Hi
>
> > Yes this optimization can be done, I will handle this in the next patch
> > set.
> >
>
> I have a suggestion for the parallel safety-check.
>
> As designed, The leader does not participate in the insertion of data.
> If User use (PARALLEL 1), there is only one worker process which will do the insertion.
>
> IMO, we can skip some of the safety-check in this case, becase the safety-check is to limit parallel insert.
> (except temporary table or ...)
>
> So, how about checking (PARALLEL 1) separately ?
> Although it looks a bit complicated, But (PARALLEL 1) do have a good performance improvement.
>

Thanks for the comments Hou Zhijie, I will run a few tests with 1
worker and try to include this in the next patch set.

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