The last packet sent successfully to the server was 零 milliseconds ago-数据库教程-爱易网页

The last packet sent successfully to the server was 零 milliseconds ago

日期：2014-05-16　浏览次数：20540 次

The last packet sent successfully to the server was 0 milliseconds ago.
今天在使用JDBC操作mysql时遇到下面的异常信息：

引用

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at com.tomymap.galaxy.virgo.util.DbService.getConnection(DbService.java:66)
at com.tomymap.galaxy.virgo.util.DbService.getConnection(DbService.java:46)
at com.tomymap.galaxy.virgo.dao.PNNDao.getConnection(PNNDao.java:51)
at com.tomymap.galaxy.virgo.dao.DaoBase.executeUpdate(DaoBase.java:69)
at com.tomymap.galaxy.virgo.dao.PNNDao.updatePNNRelation(PNNDao.java:161)
at com.tomymap.galaxy.virgo.pnn.PyramidNeuralNetwork.buildPNNRelations(PyramidNeuralNetwork.java:400)
at com.tomymap.galaxy.virgo.pnn.PyramidNeuralNetwork.incrementalGenPNN(PyramidNeuralNetwork.java:144)
at com.tomymap.galaxy.virgo.pnn.PyramidNeuralNetwork.main(PyramidNeuralNetwork.java:410)

着实让人崩溃的信息，花费了一天的时间来解决。
不罗嗦，直接描述解决办法。

配置：
ubuntu10.10
5.1.49-1ubuntu8.1
mysql-connector-java-5.1.18.jar

交互：
300k records
300k * 10 = 3M次访问mysql
处理时间0.5h以内

解决方法：
（1）使用JDBC URL中使用autoReconnect属性，url添加

&autoReconnect=true&failOverReadOnly=false&maxReconnects=10

（2）修改MySQL的参数. /etc/my.cnf 添加

[mysqld]
wait_timeout=31536000
interactive_timeout=31536000

（3）重启mysql

service mysql restart

原因分析：
（1）大量数据访问情况下，mysql connection连接有可能失效
（2）长时间不妨问，connection会失效

更多参考：
http://dev.mysql.com/doc/refman/5.1/zh/database-administration.html#dynamic-system-variables
http://www.blogjava.net/heweiya/archive/2006/01/18/28483.html

1 楼 hhsc00 2012-05-15

连接字符串URL中，将localhost改成127.0.0.1，就OK了。

原因见：
Testing your connectivity with the mysql command-line client will not work unless you add the –host flag, and use something other than localhost for the host. The mysql command-line client will use Unix domain sockets if you use the special host name localhost. If you are testing connectivity to localhost, use 127.0.0.1 as the host name instead.

引用自：http://dev.mysql.com/doc/refman/5.0/en/connector-j-usagenotes-troubleshooting.html

我的异常网推荐解决方案：The driver has not received any packets from the server.,http://www.aiyiweb.com/j2ee/345243.html

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The last packet sent successfully to the server was 零 milliseconds ago

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