Re: ALTER SUBSCRIPTION REFRESH PUBLICATION has default copy_data = true? - Mailing list pgsql-hackers

From Bharath Rupireddy
Subject Re: ALTER SUBSCRIPTION REFRESH PUBLICATION has default copy_data = true?
Date
Msg-id CALj2ACUQZGqWOfSF0Xpc0-eFWKpmq9-3ewuHuZXx4gv=WrpP8Q@mail.gmail.com
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In response to ALTER SUBSCRIPTION REFRESH PUBLICATION has default copy_data = true?  (Peter Smith <smithpb2250@gmail.com>)
List pgsql-hackers
On Wed, Jun 2, 2021 at 6:40 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> Hi.
>
> The documentation of ALTER SUBSCRIPTION REFRESH PUBLICATION [1] says:
>
> ----------
>
> REFRESH PUBLICATION
>
> Fetch missing table information from publisher. This will start
> replication of tables that were added to the subscribed-to
> publications since the last invocation of REFRESH PUBLICATION or since
> CREATE SUBSCRIPTION.
>
> refresh_option specifies additional options for the refresh operation.
> The supported options are:
>
> copy_data (boolean)
>
> Specifies whether the existing data in the publications that are being
> subscribed to should be copied once the replication starts. The
> default is true. (Previously subscribed --tables are not copied.)
>
> ----------
>
> But I found that default copy_data = true to be unintuitive.
>
> e.g. When I had previously done the CREATE SUBSCRIPTION using
> copy_data = false, then I assumed (wrongly) that the subscription
> default would remain as copy_data = false even when doing the REFRESH
> PUBLICATION.

The fact is that the options copy_data, create_slot and connect are
not stored in the catalog pg_subscription (actually they don't need to
be). Among these the copy_data option can be specified in the ALTER
... SUBSCRIPTION.

> Is that a deliberate functionality, or is it a quirk / bug?

I don't think it's a bug. Maybe adding a note in the docs about the
options which are stored/not stored in the pg_subscription catalog
would help.

With Regards,
Bharath Rupireddy.



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