Re: row filtering for logical replication

On Mon, Dec 20, 2021 at 8:41 AM houzj(dot)fnst(at)fujitsu(dot)com
<houzj(dot)fnst(at)fujitsu(dot)com> wrote:
>
> On Fri, Dec 17, 2021 6:09 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > On Fri, Dec 17, 2021 at 4:11 AM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> > >
> > > PSA the v47* patch set.
> Thanks for the comments, I agree with all the comments.
> Attach the V49 patch set, which addressed all the above comments on the 0002
> patch.

While reviewing the patch, I was testing a scenario where we change
the row filter condition and refresh the publication, in this case we
do not identify the row filter change and the table data is not synced
with the publisher. In case of setting the table, we sync the data
from the publisher. I'm not sure if the behavior is right or not.
Publisher session(setup publication):
---------------------------------
create table t1(c1 int);
insert into t1 values(11);
insert into t1 values(12);
insert into t1 values(1);
select * from t1;
c1
----
11
12
1
(3 rows)
create publication pub1 for table t1 where ( c1 > 10);

Subscriber session(setup subscription):
---------------------------------
create table t1(c1 int);
create subscription sub1 connection 'dbname=postgres host=localhost'
publication pub1;
select * from t1;
c1
----
11
12
(2 rows)

Publisher session(alter the row filter condition):
---------------------------------
alter publication pub1 set table t1 where ( c1 < 10);

Subscriber session(Refresh):
---------------------------------
alter subscription sub1 refresh publication ; -- After refresh, c1
with 1 is not fetched
select * from t1;
c1
----
11
12
(2 rows)

Should we do a table sync in this case, or should the user handle this
scenario to take care of sync data from the publisher or should we
throw an error to avoid confusion. If existing behavior is fine, we
can document it.

Thoughts?

Regards,
Vignesh