Re: Allow logical replication to copy tables in binary format

On Thu, Aug 11, 2022 at 7:34 AM Euler Taveira <euler(at)eulerto(dot)com> wrote:
>
> On Wed, Aug 10, 2022, at 12:03 PM, Melih Mutlu wrote:
>
> I see that logical replication subscriptions have an option to enable binary [1].
> When it's enabled, subscription requests publisher to send data in binary format.
> But this is only the case for apply phase. In tablesync, tables are still copied as text.
>
> This option could have been included in the commit 9de77b54531; it wasn't.
> Maybe it wasn't considered because the initial table synchronization can be a
> separate step in your logical replication setup idk. I agree that the binary
> option should be available for the initial table synchronization.
>
> To copy tables, COPY command is used and that command supports copying in binary. So it seemed to me possible to copy in binary for tablesync too.
> I'm not sure if there is a reason to always copy tables in text format. But I couldn't see why not to do it in binary if it's enabled.
>
> The reason to use text format is that it is error prone. There are restrictions
> while using the binary format. For example, if your schema has different data
> types for a certain column, the copy will fail.
>

Won't such restrictions hold true even during replication?

--
With Regards,
Amit Kapila.