【MySQL案例】 Mysql slave中processlist time值为负数

slave中执行show processlist时，发现time值为负值。以下是解决办法

mysql-slave1> select user,host, time, state from information_schema.processlist where user='system user';
+-------------+------+-------+------------------------------------------------------------------+
| user        | host | time  | state                                                            |
+-------------+------+-------+------------------------------------------------------------------+
| system user |      |   -11 | Slave has read all relay log; waiting for the slave I/O thread t |
| system user |      | 71875 | Waiting for master to send event                                 |
+-------------+------+-------+------------------------------------------------------------------+
2 rows in set (0.00 sec)

对比了slave和master的时间，发现slave和master时间不同步。
mysql-slave1> select now();
+---------------------+
| now()               |
+---------------------+
| 2014-12-13 13:07:20 |
+---------------------+
1 row in set (0.00 sec)

mysql-Master> select now();
+---------------------+
| now()               |
+---------------------+
| 2014-12-13 13:07:32 |
+---------------------+
1 row in set (0.00 sec)

mysql-slave1> system date;
Sat Dec 13 13:09:47CST 2014

mysql-Master> system date;
Sat Dec 13 13:09:59 CST 2014

在slave上手工做时间同步后，问题解决。
# /usr/sbin/ntpdate 192.168.1.10; /sbin/hwclock -w
13 Dec 13:12:05 ntpdate[32067]: step time server 192.168.1.10 offset 11.503421 sec

mysql-slave1> select user,host, time, state from information_schema.processlist where user='system user';
+-------------+------+-------+------------------------------------------------------------------+
| user        | host | time  | state                                                            |
+-------------+------+-------+------------------------------------------------------------------+
| system user |      |     0 | Slave has read all relay log; waiting for the slave I/O thread t |
| system user |      | 72302 | Waiting for master to send event                                 |
+-------------+------+-------+------------------------------------------------------------------+