今天在使用JDBC操作mysql时遇到下面的异常信息:
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打赏