Re: Report replica identity in pg_publication_tables

On Wed, Jul 2, 2025 at 1:46 PM Zhijie Hou (Fujitsu)
<houzj.fnst@fujitsu.com> wrote:

>
> I'm concerned about whether we can correctly display replica identity in the
> view for partitioned tables.
>
> In the case of partitioned tables, we display only the root table in the view
> if publish_via_partition_root is enabled for the publication. However, the
> logged information depends on the replica identity (RI) of each child
> partition. Displaying only the root table's RI could be a bit confusing since
> each partition might have different RI settings, making it challenging to
> represent all of them in the entry for the root table.
>

I see following possibilities:
1. If a publication has publish_via_partition_root true, then for all
the partitioned tables we show "partitioned" or "partition root" in
replica identity column with a note in documentation that it means
that the replica identity of the actual leaf partition would be used
instead of replica identity of the partitioned table. And then it will
be for the user to find out all the replica identities.
2. If a publication has publish_via_partition_root true, then for all
the partitioned tables we show a set of distinct replica identities of
the leaf partitions. That way, if all the leaf partitions have the
same replica identity setting, that will be reported. Otherwise, the
user will be able to know all the possible replica identity settings
that may be used. Again, documentation should clarify what this value
means for a partitioned table. But then somehow we need to indicate
whether a given table is partitioned or not.
3. We report "partitioned" or "partition root" followed by all the
distinct replica identities, thus letting the user know that the table
is partitioned and what replica identity settings its partitions have.
And document.

Since the targeted use of this column is to know the replica
identities of the tables published by a given publication so that they
can guess what might be WAL logged, these options seem ok along with
the clarifying documentation.

What do you think?
--
Best Wishes,
Ashutosh Bapat