MySql运行状态分析

问题来源问题分析解决方案：

问题来源

测试环境在执行过程中发现链接数据库超时了，运行错误日记如下：

org.springframework.transaction.CannotCreateTransactionException: Could not open JDBC Connection for transaction; nested exception is com.alibaba.druid.pool.GetConnectionTimeoutException: wait millis 60000, active 30, maxActive 30 at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:245) ~[spring-jdbc-4.2.1.RELEASE.jar:4.2.1.RELEASE] at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:373) ~[spring-tx-4.2.1.RELEASE.jar:4.2.1.RELEASE] at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:427) ~[spring-tx-4.2.1.RELEASE.jar:4.2.1.RELEASE] at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:276) ~[spring-tx-4.2.1.RELEASE.jar:4.2.1.RELEASE] at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.2.1.RELEASE.jar:4.2.1.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.2.1.RELEASE.jar:4.2.1.RELEASE] at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.2.1.RELEASE.jar:4.2.1.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.2.1.RELEASE.jar:4.2.1.RELEASE] at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207) ~[spring-aop-4.2.1.RELEASE.jar:4.2.1.RELEASE]

问题分析

检查网络是通畅 经过telent 命令确认网络是正常的。mysql端口也是可以正常访问的。检查链接数是否足够 使用show full processlist命令查看数据库当前连接数。发现某个PC的N个链接一直在休眠没有释放，导致数据库链接不够用导致的。

解决方案：

将改pc的进程kill掉，释放出链接。 命令：KILL [CONNECTION | QUERY] processlist_id修改系统最大链接数。使用命令修改或修改配置文件。命令：set global max_connections=1000;