presto-main/src/main/java/io/prestosql/execution/CreateTableTask.java/CreateTableTask/combineProperties
class CreateTableTask:    private static Map<String, Object> combineProperties(Set<String> specifiedPropertyKeys, Map<String, Object> defaultProperties, Map<String, Object> inheritedProperties)
    {
        Map<String, Object> finalProperties = new HashMap<>(inheritedProperties);
        for (Map.Entry<String, Object> entry : defaultProperties.entrySet()) {
            if (specifiedPropertyKeys.contains(entry.getKey()) || !finalProperties.containsKey(entry.getKey())) {
                finalProperties.put(entry.getKey(), entry.getValue());
            }
        }
        return finalProperties;
    }