presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/UserTableKey.java/UserTableKey/toString
class UserTableKey:    @Override
    public String toString()
    {
        return toStringHelper(this)
                .add("principal", principal)
                .add("table", table)
                .add("database", database)
                .add("owner", owner)
                .toString();
    }