Re: Proposal: Conflict log history table for Logical Replication - Mailing list pgsql-hackers

On Thu, Dec 4, 2025 at 4:20 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Thu, Dec 4, 2025 at 10:49 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> > > ---
> > > I think the conflict history table should not be transferred to the
> > > new cluster when pg_upgrade since the table definition could be
> > > different across major versions.
> >
> > Let me think more on this with respect to behaviour of other factors
> > like subscriptions etc.
> >
>
> Can we deal with different schema of tables across versions via
> pg_dump/restore during upgrade?
>

While handling the case of conflict_log_table option during pg_dump, I
realized that the restore is trying to create conflict log table 2
different places 1) As part of the regular table dump 2) As part of
the CREATE SUBSCRIPTION when conflict_log_table option is set.

So one option is we can avoid dumping the conflict log tables as part
of the regular table dump if we think that we do not need to conflict
log table data and let it get created as part of the create
subscription command, OTOH if we think we want to keep the conflict
log table data, let it get dumped as part of the regular tables and in
CREATE SUBSCRIPTION we will just set the option but do not create the
table, although we might need to do special handling of this case
because if we allow the existing tables to be set as conflict log
tables then it may allow other user tables to be set, so need to think
how to handle this if we need to go with this option.

--
Regards,
Dilip Kumar
Google