Function GetTableAmRoutineByAmId

src/backend/access/table/tableamapi.c:119–144

* GetTableAmRoutineByAmId - look up the handler of the table access method * with the given OID, and get its TableAmRoutine struct. * * If the given OID isn't a valid index access method, throws error. */

 * If the given OID isn't a valid index access method, throws error.
 */
const TableAmRoutine *
GetTableAmRoutineByAmId(Oid amoid)
{
	HeapTuple	tuple;
	Form_pg_am  amform;
	regproc     amhandler;

	if (amoid == HEAP_TABLE_AM_OID)
		return GetHeapamTableAmRoutine();

	tuple = SearchSysCache1(AMOID, ObjectIdGetDatum(amoid));
	if (!HeapTupleIsValid(tuple))
		ereport(ERROR, (errmsg("cache lookup failed for access method %u", amoid)));

	amform = (Form_pg_am) GETSTRUCT(tuple);
	if (amform->amtype != AMTYPE_TABLE)
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("access method \"%s\" is not of type TABLE",
						NameStr(amform->amname))));

	amhandler = amform->amhandler;
	ReleaseSysCache(tuple);

	return GetTableAmRoutine(amhandler);
}

/* check_hook: validate new default_table_access_method */
bool