数据库连接异常的解决过程

以你之姓@ 2022-07-13 17:20 191阅读 0赞

首先先简述一下遇到的问题，今天早上来了之后，网站突然报404的问题，不废话，直接看tomcat的日志吧，日志如下：

### Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 87,122,326 milliseconds ago. The last packet sent successfully to the server was 87,122,533 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.
 ### The error may exist in com/shishuo/cms/dao/ArticleDao.xml
 ### The error may involve defaultParameterMap
 ### The error occurred while setting parameters
 ### SQL: select count(*) from article where path like ?"%" and status = 'display' and `check` = 'yes'
 ### Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 87,122,326 milliseconds ago. The last packet sent successfully to the server was 87,122,533 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.
 ; SQL []; The last packet successfully received from the server was 87,122,326 milliseconds ago. The last packet sent successfully to the server was 87,122,533 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.; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 87,122,326 milliseconds ago. The last packet sent successfully to the server was 87,122,533 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 org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:99)
 	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
 	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
 	at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73)
 	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:368)
 	at $Proxy12.selectOne(Unknown Source)
 	at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:163)
 	at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:63)
 	at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:43)
 	at $Proxy21.getArticleCountOfDisplayByPath(Unknown Source)
 	at com.shishuo.cms.service.ArticleService.getArticlePageByFolderId(ArticleService.java:288)
 	at com.shishuo.cms.service.ArticleService.getPictureArticle(ArticleService.java:419)
 	at com.shishuo.cms.service.ArticleService$$FastClassBySpringCGLIB$$a703cd95.invoke(<generated>)
 	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
 	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:629)
 	at com.shishuo.cms.service.ArticleService$$EnhancerBySpringCGLIB$$facc1f69.getPictureArticle(<generated>)
 	at com.lvsuo.portal.controller.IndexController.index(IndexController.java:50)
 	at com.lvsuo.portal.controller.IndexController.home(IndexController.java:39)
 	at sun.reflect.GeneratedMethodAccessor74.invoke(Unknown Source)
 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 	at java.lang.reflect.Method.invoke(Method.java:597)
 	at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:685)
 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:919)
 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:851)
 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)
 	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:844)
 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:106)
 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
 	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
 	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
 	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
 	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
 	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
 	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
 	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
 	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
 	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
 	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)
 	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
 	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
 	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
 	at java.lang.Thread.run(Thread.java:662)
 Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 87,122,326 milliseconds ago. The last packet sent successfully to the server was 87,122,533 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.GeneratedConstructorAccessor42.newInstance(Unknown Source)
 	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
 	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
 	at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
 	at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121)
 	at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3938)
 	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2551)
 	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2731)
 	at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2815)
 	at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
 	at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1379)
 	at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
 	at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
 	at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:56)
 	at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:70)
 	at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:57)
 	at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:259)
 	at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:132)
 	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:105)
 	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:81)
 	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:104)
 	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:98)
 	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:62)
 	at sun.reflect.GeneratedMethodAccessor41.invoke(Unknown Source)
 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 	at java.lang.reflect.Method.invoke(Method.java:597)
 	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:358)
 	... 50 more
 Caused by: java.net.SocketException: Broken pipe
 	at java.net.SocketOutputStream.socketWrite0(Native Method)
 	at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
 	at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
 	at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
 	at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
 	at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3919)
 	... 71 more

这是全部的报错信息了，没有细读错误，我感觉肯定是数据库连接池的问题，因为现在很多网站都连接到这个mysql数据库，所以我猜想应该是数据库连接数不太够用引起的问题，虽然是这样猜想，但是也需要确切的答案，所以还是要读一下异常信息，大致如下：

“从服务器成功地接收数据包是在87,122,326毫秒（1.0083602天）以前，最近往服务器发送成功的数据包是在87,122,533毫秒（1.0083626天）前，大于服务器配置的wait\_timeout的值，你应该在使用应用之前，过期掉或者测试连接有效性，增加客户端过期时间的配置，或者使用autoReconnect=true来避免这个问题"。

查看一下MySQL的配置，如下：

28800也就是8个小时的时间，所以肯定是连接过期了。

从服务器说的话基本上已经很明显了，是因为数据库很长时间没有使用，导致了数据库和客户端之间的连接断开了，而且也提到了几种解决方式，如下：

第一种（不推荐使用）：增大wait\_timeout的值，这种方式属于饮鸩止渴了，我可以配置过期时间为1年，但是这样增加了服务器的负担，让服务器的连接没有断开刷新的可能，而且，官网本来访问量就很小，如果增加wait\_timeout的值，恰恰在这时间内没有访问，那么又会出现这个问题，所以，不使用这种方法。

第二种（不推荐使用）：在连接中使用autoReconnect=true，这个办法在错误信息提示中已经说过了，但是问题是，现在使用的并不是JDBC连接，而是使用的Sping来管理DBCP数据库连接池，连接的数据库连接使用JDBC的办法肯定是不合时宜的，而且DBCP肯定有相应的办法来解决该问题。

第三种（推荐）：使用DBCP的办法来验证连接有效性，可以直接从源码中找一下响应的方法，如下：

/** 
 * Sets the {@link #validationQuery}.
 * 
 * Note: this method currently has no effect once the pool has been
 * initialized. The pool is initialized the first time one of the
 * following methods is invoked: <code>getConnection, setLogwriter,
 * setLoginTimeout, getLoginTimeout, getLogWriter.</code>
 * 
 * @param validationQuery the new value for the validation query
 */
 public void setValidationQuery(String validationQuery) {
 if ((validationQuery != null) && (validationQuery.trim().length() > 0)) {
 this.validationQuery = validationQuery;
 } else {
 this.validationQuery = null;
 }
 this.restartNeeded = true;
 }

/**
 * The SQL query that will be used to validate connections from this pool
 * before returning them to the caller. If specified, this query
 * MUST be an SQL SELECT statement that returns at least
 * one row.
 */
 protected volatile String validationQuery = null;

/**
         * The indication of whether objects will be validated before being
         * borrowed from the pool.  If the object fails to validate, it will be
         * dropped from the pool, and we will attempt to borrow another.
         */
        protected boolean testOnBorrow = true;

上面的意思是这样的，当从数据库连接池中获取连接的时候，会先验证连接的有效性，如果失败了的话，会继续请求另外的一个连接，所以，dbcp的配置修改为如下的配置：

这样，将网站的所有配置都更新掉就可以了。