Horton

Re: Proposal: Conflict log history table for Logical Replication

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: shveta malik <shveta.malik@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-11-17T06:24:11Z
Lists: pgsql-hackers

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  1. Allow logical replication conflicts to be logged to a table.

  2. Avoid orphaned objects dependencies

Attachments

On Thu, Nov 13, 2025 at 9:17 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Thu, Nov 13, 2025 at 2:39 PM shveta malik <shveta.malik@gmail.com> wrote:
> >
> > > Few observations related to publication.
> > > ------------------------------
>
> Thanks Shveta, for testing and sharing your thoughts.  IMHO for
> conflict log tables it should be good enough if we restrict it when
> ALL TABLE options are used, I don't think we need to put extra effort
> to completely restrict it even if users want to explicitly list it
> into the publication.
>
> > >
> > > (In the below comments, clt/CLT implies Conflict Log Table)
> > >
> > > 1)
> > > 'select pg_relation_is_publishable(clt)' returns true for conflict-log table.

After putting more thought I have changed this to return false for
clt, as this is just an exposed function not called by pgoutput layer.

> > > 2)
> > > '\d+ clt'   shows all-tables publication name. I feel we should not
> > > show that for clt.
>
Fixed

>
> > > 3)
> > > I am able to create a publication for clt table, should it be allowed?
>
> I believe we should not do any specific handling to restrict this but
> I am open for the opinions.

Restricting this as well, lets see what others think.


>
> > > 5) Also, I feel we can add some documentation now to help others to
> > > understand/review the patch better without going through the long
> > > thread.
>
> Make sense, I will do that in the next version.
Done that but not compiled the docs as I don't currently have the
setup so added as WIP patch.


> > > 2)
> > > Conflicts where row on sub is missing, local_ts incorrectly inserted.
> > > It is '2000-01-01 05:30:00+05:30'. Should it be Null or something
> > > indicating that it is not applicable for this conflict-type?
> > >
> > > Example: delete_missing, update_missing
> > > pub:
> > >  insert into tab1 values(10,10);
> > >  insert into tab1 values(20,10);
> > >  sub:  delete from tab1 where i=10;
> > >  pub:  delete from tab1 where i=10;
>
> Sure I will test this.

I have fixed this.

-- 
Regards,
Dilip Kumar
Google