Re: row filtering for logical replication - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: row filtering for logical replication
Date
Msg-id CAA4eK1JaxY_wDJeuJHJuUcrX318=5RtXo96tLVOcJzhOW6+5gw@mail.gmail.com
Whole thread Raw
In response to Re: row filtering for logical replication  (Peter Smith <smithpb2250@gmail.com>)
List pgsql-hackers
On Fri, Nov 19, 2021 at 3:16 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> On Thu, Nov 18, 2021 at 4:32 PM Peter Smith <smithpb2250@gmail.com> wrote:
> >
> > On Mon, Nov 15, 2021 at 9:31 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > > On Wed, Nov 10, 2021 at 12:36 PM Peter Smith <smithpb2250@gmail.com> wrote:
> > > >
> > > > On Mon, Nov 8, 2021 at 5:53 PM houzj.fnst@fujitsu.com
> > > > <houzj.fnst@fujitsu.com> wrote:
> > > > >
> > > > > 3) v37-0005
> > > > >
> > > > > - no parse nodes of any kind other than Var, OpExpr, Const, BoolExpr, FuncExpr
> > > > >
> > > > > I think there could be other node type which can also be considered as simple
> > > > > expression, for exmaple T_NullIfExpr.
> > > >
> > > > The current walker restrictions are from a previously agreed decision
> > > > by Amit/Tomas [1] and from an earlier suggestion from Andres [2] to
> > > > keep everything very simple for a first version.
> > > >
> > > > Yes, you are right, there might be some additional node types that
> > > > might be fine, but at this time I don't want to add anything different
> > > > without getting their approval to do so. Anyway, additions like this
> > > > are all candidates for a future version of this row-filter feature.
> > > >
> > >
> > > I think we can consider T_NullIfExpr unless you see any problem with the same.
> >
> > Added in v40 [1]
> >
>
> I've noticed that row-filters that are testing NULL cannot pass the
> current expression validation restrictions.
>
> e.g.1
> test_pub=# create publication ptest for table t1 where (a is null);
> ERROR:  invalid publication WHERE expression for relation "t1"
> HINT:  only simple expressions using columns, constants and immutable
> system functions are allowed
>
> e.g.2
> test_pub=# create publication ptest for table t1 where (a is not null);
> ERROR:  invalid publication WHERE expression for relation "t1"
> HINT:  only simple expressions using columns, constants and immutable
> system functions are allowed
>
> So I think it would be useful to permit the NullTest also. Is it OK?
>

Yeah, I think such simple expressions should be okay but we need to
test left-side expressions for simplicity.

-- 
With Regards,
Amit Kapila.



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