About MySQL's wait_timeout connection timeout problem error reporting solution

The default "wait_timeout" of the Mysql server is 8 hours [that is, the default value is 28800 seconds by default], which means that a connection is idle for more than 8 hours, and Mysql will automatically disconnect the connection. If there is no activity, the connection is automatically disconnected. The value of wait timeout can be set, but it can only be up to 2147483, and cannot be larger. That is about 24.85 days so even if you add # this is myown dinifition for mysql connection timeout wait_timeout=31536000 interactive_timeout=31536000 under # The TCP/IP Port the MySQL Server will listen on port=3306 via my.ini How big the value is, can only be parsed by MySQL as 2147483, what should be wrong with your program after 2147483 days or what is wrong, the unavoidable

1.1 error message:

Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 20,820,001 milliseconds ago.  The last packet sent successfully to the server was 20,820,002 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
at sun.reflect.GeneratedConstructorAccessor29.newInstance(Unknown Source) ~[na:na]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.7.0_51]
at java.lang.reflect.Constructor.newInstance(Constructor.java:526) ~[na:1.7.0_51]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.29.jar:na]
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1129) ~[mysql-connector-java-5.1.29.jar:na]
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3988) ~[mysql-connector-java-5.1.29.jar:na]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2598) ~[mysql-connector-java-5.1.29.jar:na]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2778) ~[mysql-connector-java-5.1.29.jar:na]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2828) ~[mysql-connector-java-5.1.29.jar:na]
at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:5372) ~[mysql-connector-java-5.1.29.jar:na]
at com.mchange.v2.c3p0.impl.NewProxyConnection.setAutoCommit(NewProxyConnection. java:881) ~[c3p0-0.9.1.1.jar:0.9.1.1]
at org.quartz.impl.jdbcjobstore.AttributeRestoringConnectionInvocationHandler.setAutoCommit(AttributeRestoringConnectionInvocationHandler.java:98) ~[quartz-2.2.1.jar:na]
1.2 Workaround

- If using JDBC, add ?autoReconnect=true to the JDBC URL, eg:

jdbc:mysql://10.10.10.10:3306/mydb?autoReconnect=true
- If using DBCP connection pooling in Spring, in Define datasource to add attributes validationQuery and testOnBorrow, such as:

<bean id="vrsRankDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="${jdbc.driverClassName}" />
    <property name="url" value="${countNew.jdbc.url}" />
    <property name="username" value="${countNew.jdbc.user}" />
    <property name="password" value="${countNew.jdbc.pwd}" />
    <property name="validationQuery" value="SELECT 1" />
    <property name="testOnBorrow" value="true"/>
</bean>
- 如果是在Spring中使用c3p0连接池，则在定义datasource的时候，添加属性testConnectionOnCheckin和testConnectionOnCheckout，如：

<bean name="cacheCloudDB" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <property name="driverClass" value="${jdbc.driver}"/>
    <property name="jdbcUrl" value="${cache.url}"/>
    <property name="user" value="${cache.user}"/>
    <property name="password" value="${cache.password}"/>
    <property name="initialPoolSize" value="10"/>
    <property name="maxPoolSize" value="${cache.maxPoolSize}"/>
    <property name="testConnectionOnCheckin" value="false"/>
    <property name="testConnectionOnCheckout" value="true"/>
    <property name="preferredTestQuery" value="SELECT 1"/>
</bean>
参考

MySQL reconnect issues


附录分析

When a c3p0-proxied Connection throws an SQLException,c3p0 examines 
the Exception and the Connection to make a judgement about whether 
the problem implies that the Connection should no longer be included 
in the pool. c3p0 tests the Connection, and if the test fails,  the 
Connection will be excluded from the pool.

What c3p0 is telling you here is that a Connection that previously 
signalled an error and then failed a Connection test is still in use, 
and has signalled another error. From c3p0's perspective, this is a 
non-issue, it just means c3p0 doesn't have to do any kind of checks 
or notifications, the Connection is already gone as far as the pool 
is concerned. But c3p0 wonders why you'd still be using such a 
Connection, and warns you about it.

Usually, if a client continues to use a Connection that c3p0 has 
correctly identified as broken, all further uses will provoke such an 
exception, and the fix is to close the Connection and start over when 
an application's Connection turns out to be dead. But, by the error 
you're getting, it looks like your Connection is still live and okay 
-- it's clearly communicating with the database. So, the issue is, 
why did c3p0 deem the Connection dead if it is not?

If you turn on DEBUG level logging (relevant loggers would be 
com.mchange.v2.c3p0.impl.NewPooledConnection, 
com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool, and 
com.mchange.v2.c3p0.impl.DefaultConnectionTester, unless you've 
defined your own ConnectionTester), you can trace the testing and 
invalidation of Connections, and try to understand why Connections 
that seem okay are testing as broken. That will give you better 
information about what's going on.

That said, the only cost of this behavior is disconcerting warning 
messages and somewhat faster churn of Connections through the pool. 
c3p0 is erring on the side of caution -- it has reason to believe a 
Connection is bad, so it's been excluded from the pool. It'd be nice 
to know why apparently good Connections are failing Connection tests, 
but if it is an infrequent occurrence, it's very little to worry 
about. (If it's happening a lot, you should track it down.)
原文地址：http://sourceforge.net/p/c3p0/mailman/message/18310863/


mysql重连，连接丢失：The last packet successfully received from the server--转载

http://www.cnblogs.com/davidwang456/p/4425913.html