Re: Handle infinite recursion in logical replication setup

On Mon, Sep 5, 2022 at 9:47 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> Here are my review comments for v45-0001:
>
> ======
>
> 1. doc/src/sgml/logical-replication.sgml
>
>   <para>
>    To find which tables might potentially include non-local origins (due to
>    other subscriptions created on the publisher) try this SQL query:
> <programlisting>
> SELECT DISTINCT N.nspname AS schemaname, C.relname AS tablename
> FROM pg_publication P,
>      LATERAL pg_get_publication_tables(P.pubname) GPT
>      LEFT JOIN pg_subscription_rel PS ON (GPT.relid = PS.srrelid),
>      pg_class C JOIN pg_namespace N ON (N.oid = C.relnamespace)
> WHERE C.oid = GPT.relid AND PS.srrelid IS NOT NULL AND
>       P.pubname IN (pub-names);
> </programlisting></para>
>
> 1a.
> To use "<pub-names>" with the <> then simply put meta characters in the SGML.
> e.g.
> &lt;pub-names&gt;
>
> ~
>
> 1b.
> The patch forgot to add the SQL "#" instruction as suggested by my
> previous comment (see [1] #3b)
>
> ~~~
>
> 2.
>
>  <sect1 id="preventing-inconsistencies-for-copy_data-origin">
>   <title>Preventing Data Inconsistencies for copy_data, origin=NONE</title>
>
> The title is OK, but I think this should all be a <sect2> sub-section
> of "31.2 Subscription"
>
> ======
>

It is recommended to create the subscription
+   using <literal>enabled=false</literal>, so that if the origin WARNING occurs
+   no copy has happened yet. Otherwise some corrective steps might be needed to
+   remove any unwanted data that got copied.

I am not completely sure of this part of the docs as this can add
additional steps for users while working on subscriptions even when
the same is not required. I suggest for now we can remove this part.
Later based on some feedback on this feature, we can extend the docs
if required.

Also, instead of having it as a separate section, let's keep this as
part of create_subscription.sgml

*
+ errhint("Verify that initial data copied from the publisher tables
did not come from other origins. Some corrective action may be
necessary."));

The second sentence in this message doesn't seem to be required.


-- 
With Regards,
Amit Kapila.