Re: Column Filtering in Logical Replication

On Thu, Aug 25, 2022 at 7:38 PM vignesh C <vignesh21(at)gmail(dot)com> wrote:
>
...
> > PSA the v3* patch set.
>
> Thanks for the updated patch.
> Few comments:
> 1) We can shuffle the columns in publisher table and subscriber to
> show that the order of the column does not matter
> + <para>
> + Create a publication <literal>p1</literal>. A column list is defined for
> + table <literal>t1</literal> to reduce the number of columns that will be
> + replicated.
> +<programlisting>
> +test_pub=# CREATE PUBLICATION p1 FOR TABLE t1 (id, a, b, c);
> +CREATE PUBLICATION
> +test_pub=#
> +</programlisting></para>
>

OK. I made the following changes to the example.
- now the subscriber table defines cols in a different order than that
of the publisher table
- now the publisher column list defines col names in a different order
than that of the table
- now the column list avoids using only adjacent column names

> 2) We can try to keep the line content to less than 80 chars
> + <para>
> + A column list is specified per table following the tablename, and
> enclosed by
> + parenthesis. See <xref linkend="sql-createpublication"/> for details.
> + </para>
>

OK. Modified to use < 80 chars

> 3) tablename should be table name like it is used in other places
> + <para>
> + A column list is specified per table following the tablename, and
> enclosed by
> + parenthesis. See <xref linkend="sql-createpublication"/> for details.
> + </para>
>

Sorry, I don't see this problem. AFAIK this same issue was already
fixed in the v3* patches. Notice in the cited fragment that
'parenthesis' is misspelt but that was also fixed in v3. Maybe you are
looking at an old patch file (??)

> 4a) In the below, you could include mentioning "Only the column list
> data of publication <literal>p1</literal> are replicated."
> + <para>
> + Insert some rows to table <literal>t1</literal>.
> +<programlisting>
> +test_pub=# INSERT INTO t1 VALUES(1, 'a-1', 'b-1', 'c-1', 'd-1', 'e-1');
> +INSERT 0 1
>

OK. Modified to say this.

> 4b) In the above, we could mention that the insert should be done on
> the "publisher side" as the previous statements are executed on the
> subscriber side.

OK. Modified to say this.

~~~

Thanks for the feedback.

PSA patch set v4* where all of the above comments are now addressed.

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