PG17 introduced ALTER TABLE ... SET ACCESS METHOD DEFAULT
This PR introduces and enforces an error check preventing ALTER TABLE
... SET ACCESS METHOD DEFAULT on both Citus local tables (added via
citus_add_local_table_to_metadata) and distributed/partitioned
distributed tables. The regression tests now demonstrate that each table
type raises an error advising users to explicitly specify an access
method, rather than relying on DEFAULT. This ensures consistent behavior
across local and distributed environments in Citus.
The reason why we currently don't support this is that we can't simply
propagate the command as it is, because the default table access method
may be different across Citus cluster nodes.
Relevant PG commit:
https://github.com/postgres/postgres/commit/d61a6cad6