Horton

Re: Parallel copy

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-11-11T17:12:24Z
Lists: pgsql-hackers

Commits

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  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 Tue, Nov 10, 2020 at 7:27 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Nov 10, 2020 at 7:12 PM vignesh C <vignesh21@gmail.com> wrote:
> >
> > On Tue, Nov 3, 2020 at 2:28 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> >
> > I have worked to provide a patch for the parallel safety checks. It
> > checks if parallely copy can be performed, Parallel copy cannot be
> > performed for the following a) If relation is temporary table b) If
> > relation is foreign table c) If relation has non parallel safe index
> > expressions d) If relation has triggers present whose type is of non
> > before statement trigger type e) If relation has check constraint
> > which are not parallel safe f) If relation has partition and any
> > partition has the above type. This patch has the checks for it. This
> > patch will be used by parallel copy implementation.
> >
>
> How did you ensure that this is sufficient? For parallel-insert's
> patch we have enabled parallel-mode for Inserts and ran the tests with
> force_parallel_mode to see if we are not missing anything. Also, it
> seems there are many common things here w.r.t parallel-insert patch,
> is it possible to prepare this atop that patch or do you have any
> reason to keep this separate?
>

I have done similar testing for copy too, I had set force_parallel
mode to regress, hardcoded in the code to pick parallel workers for
copy operation and ran make installcheck-world to verify. Many checks
in this patch are common between both patches, but I was not sure how
to handle it as both the projects are in-progress and are being
updated based on the reviewer's opinion. How to handle this?
Thoughts?

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