Re: Proposal: Conflict log history table for Logical Replication

On Mon, Jun 22, 2026 at 8:52 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> >
> I have merged Amit's patch and Nisha's tap test patch and tested all
> the cases discussed, and those are working fine.
>

Thanks Dilip, few initial comments on 001+002:

1)
+        if (IsConflictLogTableNamespace(relnamespace))
+            ereport(ERROR,
+                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                     errmsg("permission denied to create \"%s\"",
+                            get_qualified_objname(relnamespace, relname)),
+                     errdetail("Conflict schema modifications are
currently disallowed.")));


Unable to reproduce the error. Perhaps this change is not needed after
the change made in pg_namespace_aclmask_ext() in 002? create table,
create view inside pg_conflict errors out in
RangeVarGetAndCheckCreationNamespace itself doing schema-permission
check.

2)
Same with this:
+
+ /* similarly for conflict schema */
+ if (nspOid == PG_CONFLICT_NAMESPACE || oldNspOid == PG_CONFLICT_NAMESPACE)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot move objects into or out of the conflict schema")));

I get these errors:

postgres=# alter table tab2 set schema conf;
ERROR:  42501: permission denied for schema conf
LOCATION:  aclcheck_error, aclchk.c:2813


3)

create_conflict_log_table()
+
+    /*
+     * Check for an existing table with the same name in the
pg_conflict namespace.
+     * A collision should not occur under normal operation, but we
must handle cases
+     * where a table has been created manually when allow_system_tables_mods is
+     * ON.
+     */
+    if (OidIsValid(get_relname_relid(relname, PG_CONFLICT_NAMESPACE)))
+        ereport(ERROR,
+                (errcode(ERRCODE_DUPLICATE_TABLE),
+                 errmsg("conflict log table pg_conflict.\"%s\"
already exists", relname),
+                 errhint("To proceed, drop the existing table and retry.")));

Should we replace this with 'Assert' since we can no longer create
tables inside the 'pg_conflict' schema, even with
'allow_system_table_mods=ON'?

thanks
Shveta