Re: Proposal: Conflict log history table for Logical Replication

On Fri, Sep 26, 2025 at 4:42 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Thu, Sep 25, 2025 at 4:19 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> >
> > On Thu, Sep 25, 2025 at 11:53 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> > >
> > > > [1]
> > > > /*
> > > > * For logical decode we need combo CIDs to properly decode the
> > > > * catalog
> > > > */
> > > > if (RelationIsAccessibleInLogicalDecoding(relation))
> > > > log_heap_new_cid(relation, &tp);
> > > >
> > >
> > > Meanwhile I am also exploring the option where we can just CREATE TYPE
> > > in initialize_data_directory() during initdb, basically we will create
> > > this type in template1 so that it will be available in all the
> > > databases, and that would simplify the table creation whether we
> > > create internally or we allow user to create it. And while checking
> > > is_publishable_class we can check the type and avoid publishing those
> > > tables.
> > >
> >
> > Based on my off list discussion with Amit, one option could be to set
> > HEAP_INSERT_NO_LOGICAL option while inserting tuple into conflict
> > history table, for that we can not use SPI interface to insert instead
> > we will have to directly call the heap_insert() to add this option.
> > Since we do not want to create any trigger etc on this table, direct
> > insert should be fine, but if we plan to create this table as
> > partitioned table in future then direct heap insert might not work.
>
> Upon further reflection, I realized that while this approach avoids
> streaming inserts to the conflict log history table, it still requires
> that table to exist on the subscriber node upon subscription creation,
> which isn't ideal.
>

I am not able to understand what exact problem you are seeing here. I
was thinking that during the CREATE SUBSCRIPTION command, a new table
with user provided name will be created similar to how we create a
slot. The difference would be that we create a slot on the
remote/publisher node but this table will be created locally.

--
With Regards,
Amit Kapila.