今天晚上一个财务子系统上线，部署完成后，测试反馈程序会抽风，一会儿正常，一会儿异常，报如下错误：
|
nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link fai |
通过查找资料，可能是wait_timeout设置过小导致的，尝试加大wait_timeout的值后，系统恢复正常。
更改过程如下：
##查看MySQL配置
[email protected]:mysql.sock [finance]>show global variables like ‘wait_timeout‘;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout | 10 |
+---------------+-------+
1 row in set (0.01 sec)
[email protected]:mysql.sock [finance]>show global variables like ‘%interactive_timeout%‘;
+---------------------+-------+
| Variable_name | Value |
+---------------------+-------+
| interactive_timeout | 28800 |
+---------------------+-------+
##先修改全局的值为300，重启后将恢复原值
[email protected]:mysql.sock [finance]>set global wait_timeout=300;
[email protected]:mysql.sock [finance]>show global variables like ‘wait_timeout‘;
+--------------------------+----------+
| Variable_name | Value |
+--------------------------+----------+
| wait_timeout | 300 |
+--------------------------+----------+
##修改my.cnf，保证MySQL重启后依然生效
[mysqld]
wait_timeout=300
## wait_timeout扩展
MySQL服务器默认的“wait_timeout”默认是28800秒即8小时，意味着如果一个连接的空闲时间超过8个小时，MySQL将自动断开该连接，而连接池却认为该连接还是有效的(因为并未校验连接的有效性)，当应用申请使用该连接时，就会导致上面的报错。
解决方法：
修改my.cnf：
[mysqld]
wait_timeout=31536000
interactive_timeout=31536000
将过期时间修改为1年。
Error Log日志如下：
The last packet successfully received from the server was 9,369 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago. ; SQL []; Communications link failure The last packet successfully received from the server was 9,369 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet successfully received from the server was 9,369 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago. at org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:98) at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:73) at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81) at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73) at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:371) at com.sun.proxy.$Proxy11.selectList(Unknown Source) at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:198) at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:119) at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:63) at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52) at com.sun.proxy.$Proxy12.searchRules(Unknown Source) at com.tianlian.order.server.finance.service.impl.poundage.WPOSPoundageServiceImpl.searchRules(WPOSPoundageServiceImpl.java:55) at com.tianlian.order.server.finance.service.impl.poundage.WPOSPoundageServiceImpl$$FastClassBySpringCGLIB$$aec2fff5.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:720) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) at com.alibaba.druid.support.spring.stat.DruidStatInterceptor.invoke(DruidStatInterceptor.java:72) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655) at com.tianlian.order.server.finance.service.impl.poundage.WPOSPoundageServiceImpl$$EnhancerBySpringCGLIB$$db4e378e.searchRules(<generated>) at com.alibaba.dubbo.common.bytecode.Wrapper0.invokeMethod(Wrapper0.java) at com.alibaba.dubbo.rpc.proxy.javassist.JavassistProxyFactory$1.doInvoke(JavassistProxyFactory.java:46) at com.alibaba.dubbo.rpc.proxy.AbstractProxyInvoker.invoke(AbstractProxyInvoker.java:72) at com.alibaba.dubbo.rpc.protocol.InvokerWrapper.invoke(InvokerWrapper.java:53) at com.alibaba.dubbo.rpc.filter.ExceptionFilter.invoke(ExceptionFilter.java:64) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91) at com.alibaba.dubbo.rpc.filter.TimeoutFilter.invoke(TimeoutFilter.java:42) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91) at com.alibaba.dubbo.monitor.support.MonitorFilter.invoke(MonitorFilter.java:75) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91) at com.alibaba.dubbo.rpc.protocol.dubbo.filter.TraceFilter.invoke(TraceFilter.java:78) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91) at com.alibaba.dubbo.rpc.filter.ContextFilter.invoke(ContextFilter.java:60) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91) at com.alibaba.dubbo.rpc.filter.GenericFilter.invoke(GenericFilter.java:112) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91) at com.alibaba.dubbo.rpc.filter.ClassLoaderFilter.invoke(ClassLoaderFilter.java:38) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91) at com.alibaba.dubbo.rpc.filter.EchoFilter.invoke(EchoFilter.java:38) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91) at com.alibaba.dubbo.rpc.protocol.dubbo.DubboProtocol$1.reply(DubboProtocol.java:108) at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.handleRequest(HeaderExchangeHandler.java:84) at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:170) at com.alibaba.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:52) at com.alibaba.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:82) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:722) Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
Error log
时间： 2024-08-07 04:33:29