Horton

RE: Allow logical replication to copy tables in binary format

Takamichi Osumi (Fujitsu) <osumi.takamichi@fujitsu.com>

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From: "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>
To: 'Melih Mutlu' <m.melihmutlu@gmail.com>, Euler Taveira <euler@eulerto.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-09-22T03:22:04Z
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 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.

Hi


Few more minor comments.

On Tuesday, August 16, 2022 2:04 AM Melih Mutlu <m.melihmutlu@gmail.com> wrote:
> 
> 
> 	My main concern is to break a scenario that was previously working (14
> -> 15) but after a subscriber upgrade
> 	it won't (14 -> 16).
> 
> Fair concern. Some cases that might break the logical replication with version
> upgrade would be:
...
> 3- Copying in binary format would work with the same schemas. Currently,
> logical replication does not require the exact same schemas in publisher and
> subscriber.
> This is an additional restriction that comes with the COPY command.
> 
> If a logical replication has been set up with different schemas and subscription
> is created with the binary option, then yes this would break things.
> This restriction can be clearly stated and wouldn't be unexpected though.
> 
> I'm also okay with allowing binary copy only for v16 or later, if you think it would
> be safer and no one disagrees with that.
> What are your thoughts?
I agree with the direction to support binary copy for v16 and later.

IIUC, the binary format replication with different data types fails even during apply phase on HEAD.
I thought that means, the upgrade concern only applies to a scenario that the user executes
only initial table synchronizations between the publisher and subscriber
and doesn't replicate any data at apply phase after that. I would say
this isn't a valid scenario and your proposal makes sense.


Best Regards,
	Takamichi Osumi