Horton

Re: Parallel copy

David Fetter <david@fetter.org>

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From: David Fetter <david@fetter.org>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Ants Aasma <ants@cybertec.at>, Alastair Turner <minion@decodable.me>, Thomas Munro <thomas.munro@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-02-18T15:11:49Z
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 Tue, Feb 18, 2020 at 06:51:29PM +0530, Amit Kapila wrote:
> On Tue, Feb 18, 2020 at 5:59 PM Ants Aasma <ants@cybertec.at> wrote:
> >
> > On Tue, 18 Feb 2020 at 12:20, Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > This is something similar to what I had also in mind for this idea.  I
> > > had thought of handing over complete chunk (64K or whatever we
> > > decide).  The one thing that slightly bothers me is that we will add
> > > some additional overhead of copying to and from shared memory which
> > > was earlier from local process memory.  And, the tokenization (finding
> > > line boundaries) would be serial.  I think that tokenization should be
> > > a small part of the overall work we do during the copy operation, but
> > > will do some measurements to ascertain the same.
> >
> > I don't think any extra copying is needed.
> 
> I am talking about access to shared memory instead of the process
> local memory.  I understand that an extra copy won't be required.

Isn't accessing shared memory from different pieces of execution what
threads were designed to do?

Best,
David.
-- 
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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