mysql> explain select ac,src,dst,sum(bytes),sum(packets),srcuser,dstuser from data where stamp > '2006-08-23 01:00:00' group by hash -> ;
+----+-------------+-------+-------+---------------+---------+---------+------+---------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+-------+---------------+---------+---------+------+---------+-------------+
| 1 | SIMPLE | data | index | stamp | PRIMARY | 16 | NULL | 5339637 | Using where |
+----+-------------+-------+-------+---------------+---------+---------+------+---------+-------------+
1 row in set (0.06 sec)