Re: Conflict detection and logging in logical replication

On Mon, Aug 19, 2024 at 11:54 AM shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
>
> On Mon, Aug 19, 2024 at 11:37 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > On Mon, Aug 19, 2024 at 9:08 AM shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
> > >
> > > On Sun, Aug 18, 2024 at 2:27 PM Zhijie Hou (Fujitsu)
> > > <houzj(dot)fnst(at)fujitsu(dot)com> wrote:
> > > >
> > > > Attach the V16 patch which addressed the comments we agreed on.
> > > > I will add a doc patch to explain the log format after the 0001 is RFC.
> > > >
> > >
> > > Thank You for addressing comments. Please see this scenario:
> > >
> > > create table tab1(pk int primary key, val1 int unique, val2 int);
> > >
> > > pub: insert into tab1 values(1,1,1);
> > > sub: insert into tab1 values(2,2,3);
> > > pub: update tab1 set val1=2 where pk=1;
> > >
> > > Wrong 'replica identity' column logged? shouldn't it be pk?
> > >
> > > ERROR: conflict detected on relation "public.tab1": conflict=update_exists
> > > DETAIL: Key already exists in unique index "tab1_val1_key", modified
> > > locally in transaction 801 at 2024-08-19 08:50:47.974815+05:30.
> > > Key (val1)=(2); existing local tuple (2, 2, 3); remote tuple (1, 2,
> > > 1); replica identity (val1)=(1).
> > >
> >
> > The docs say that by default replica identity is primary_key [1] (see
> > REPLICA IDENTITY),
>
> yes, I agree. But here the importance of dumping it was to know the
> value of RI as well which is being used as an identification of row
> being updated rather than row being conflicted. Value is logged
> correctly.
>

Agreed, sorry, I misunderstood the problem reported. I thought the
suggestion was to use 'primary key' instead of 'replica identity' but
you pointed out that the column used in 'replica identity' was wrong.
We should fix this one.

--
With Regards,
Amit Kapila.