Horton

Re: Allow logical replication to copy tables in binary format

Peter Smith <smithpb2250@gmail.com>

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From: Peter Smith <smithpb2250@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Melih Mutlu <m.melihmutlu@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>, "Takamichi Osumi (Fujitsu)" <osumi.takamichi@fujitsu.com>, Euler Taveira <euler@eulerto.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>
Date: 2023-03-03T00:32:33Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Allow logical replication to copy tables in binary format.

  2. Common function for percent placeholder replacement

  3. Doc: add XML ID attributes to <sectN> and <varlistentry> tags.

  4. Re-order disable_on_error in tab-complete.

  5. Make subscription tests pass with log_error_verbosity=verbose

  6. Weaken type-OID-matching checks in array_recv and record_recv.

  7. Allow logical replication to transfer data in binary format.

On Thu, Mar 2, 2023 at 4:00 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Thu, Mar 2, 2023 at 7:27 AM Peter Smith <smithpb2250@gmail.com> wrote:
> >
...
> > IIUC most people seem to be coming down in favour of there being a
> > single unified option (the existing 'binary==true/false) which would
> > apply to both the COPY and the data replication parts.
> >
> > I also agree
> > - Yes, it is simpler.
> > - Yes, there are various workarounds in case the COPY part failed
> >
> > But, AFAICT the main question remains unanswered -- Are we happy to
> > break existing applications already using binary=true. E.g. I think
> > there might be cases where applications are working *only* because
> > their binary=true is internally (and probably unbeknownst to the user)
> > reverting to text. So if we unified everything under one 'binary'
> > option then binary=true will force COPY binary so now some previously
> > working applications will get COPY errors requiring workarounds. Is
> > that acceptable?
> >
>
> I think one can look at this from another angle also where users would
> be expecting that when binary = true and copy_data = true, all the
> data transferred between publisher and subscriber should be in binary
> format. Users have a workaround to set binary=true only after the
> initial sync. Also, if at all, the behaviour change would be after
> major version upgrade which shouldn't be a problem.
>
> > TBH I am not sure anymore if the complications justify the patch.
> >
> > It seems we have to choose from 2 bad choices:
> > - separate options = this works but would be more confusing for the user
> > - unified option = this would be simpler and faster, but risks
> > breaking existing applications currently using 'binary=true'
> >
>
> I would prefer a unified option as apart from other things you and
> others mentioned that will be less of a maintenance burden in the
> future.

My concern was mostly just about the potential to break the behaviour
of existing binary=true applications in some edge cases.

If you are happy that doing so shouldn't be a problem, then I am also
+1 to use the unified option.

------
Kind Regards,
Peter Smith.
Fujitsu Australia