Re: row filtering for logical replication

On Fri, Nov 26, 2021 at 12:01 PM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
>
> On Fri, Nov 26, 2021 at 4:18 PM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> >
> > > > Do you mean to say that we should give an error on Update/Delete if any of the
> > > > publications contain table rowfilter that has columns that are not part of the
> > > > primary key or replica identity? I think this is what Hou-san has implemented in
> > > > his top-up patch and I also think this is the right behavior.
> > >
> > > Yes, the top-up patch will give an error if the columns in row filter are not part of
> > > replica identity when UPDATE and DELETE.
> > >
> > > But the point I want to confirm is that:
> > >

Okay, I see your point now.

> > > ---
> > > create publication A for table tbl1 where (b<2) with(publish='insert');
> > > create publication B for table tbl1 where (a>1) with(publish='update');
> > > ---
> > >
> > > When UPDATE on the table 'tbl1', is it correct to combine and execute both of
> > > the row filter in A(b<2) and B(a>1) ?(it's the current behavior)
> > >
> > > Because the filter in A has an unlogged column(b) and the publication A only
> > > publish "insert", so for UPDATE, should we skip the row filter in A and only
> > > execute the row filter in B ?
> > >
> >
> > But since the filters are OR'ed together does it even matter?
> >

Even if it is OR'ed, if the value is not logged (as it was not part of
replica identity or primary key) as per Hou-San's example, how will
evaluate such a filter?

> > Now that your top-up patch now prevents invalid updates/deletes, this
> > other point is only really a question about the cache performance,
> > isn't it?
> >
>
> Irrespective of replica identity I think there is still a functional
> behaviour question, right?
>
> e.g.
> create publication p1 for table census where (country = 'Aust') with
> (publish="update")
> create publication p2 for table census where (country = 'NZ') with
> (publish='insert')
>
> Should it be possible to UPDATE for country 'NZ' or not?
> Is this the same as your question Hou-san?
>

I am not sure if it is the same because in Hou-San's example
publications refer to different columns where one of the columns was
part of PK and another was not whereas in your example both refer to
the same column. I think in your example the error will happen at the
time of update/delete whereas in Hou-San's example it won't happen at
the time of update/delete.

With Regards,
Amit Kapila.