On Mon, Sep 16, 2024 at 8:09 PM Peter Smith <smithpb2...@gmail.com> wrote: > > I thought that the option "publish_generated_columns" is more related > to "column lists" than "row filters". > > Let's say table 't1' has columns 'a', 'b', 'c', 'gen1', 'gen2'. >
> And > PUBLICATION pub2 FOR TABLE t1 WITH (publish_generated_columns = false); > is equivalent to > PUBLICATION pub2 FOR TABLE t1(a,b,c); This makes sense to me as it preserves the current behavior. > Then: > PUBLICATION pub1 FOR TABLE t1 WITH (publish_generated_columns = true); > is equivalent to > PUBLICATION pub1 FOR TABLE t1(a,b,c,gen1,gen2); This also makes sense. It would also include future generated columns. > So, I would expect this to fail because the SUBSCRIPTION docs say > "Subscriptions having several publications in which the same table has > been published with different column lists are not supported." So I agree that it would raise an error if users subscribe to both pub1 and pub2. And looking back at your examples, > > > e.g.1 > > > ----- > > > CREATE PUBLICATION pub1 FOR TABLE t1 WITH (publish_generated_columns = > > > true); > > > CREATE PUBLICATION pub2 FOR TABLE t1 WITH (publish_generated_columns = > > > false); > > > CREATE SUBSCRIPTION sub ... PUBLICATIONS pub1,pub2; > > > ----- > > > > > > e.g.2 > > > ----- > > > CREATE PUBLICATION pub1 FOR ALL TABLES WITH (publish_generated_columns = > > > true); > > > CREATE PUBLICATION pub2 FOR TABLE t1 WITH (publish_generated_columns = > > > false); > > > CREATE SUBSCRIPTION sub ... PUBLICATIONS pub1,pub2; > > > ----- Both examples would not be supported. > > > > > > The CREATE SUBSCRIPTION docs [1] only says "Subscriptions having > > > several publications in which the same table has been published with > > > different column lists are not supported." > > > > > > Perhaps the user is supposed to deduce that the example above would > > > work OK if table 't1' has no generated cols. OTOH, if it did have > > > generated cols then the PUBLICATION column lists must be different and > > > therefore it is "not supported" (??). > > > > With the patch, how should this feature work when users specify a > > generated column to the column list and set publish_generated_column = > > false, in the first place? raise an error (as we do today)? or always > > send NULL? > > For this scenario, I suggested (see [1] #3) that the code could give a > WARNING. As I wrote up-thread: This combination doesn't seem > like something a user would do intentionally, so just silently > ignoring it (which the current patch does) is likely going to give > someone unexpected results/grief. It gives a WARNING, and then publishes the specified generated column data (even if publish_generated_column = false)? If so, it would mean that specifying the generated column to the column list means to publish its data regardless of the publish_generated_column parameter value. Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com
