最近遇到个比较奇怪的问题,用户的网站百万级访问量,最近没有修改程序,也没有改过其他地方,最近总是运行20几个小时左右tomcat就假死一次,访问无响应!!经常过检查 日志发现 里面报了一个错误

com.alibaba.druid.pool.GetConnectionTimeoutException: loopWaitCount 0, wait millis 60000
	at com.alibaba.druid.pool.DruidDataSource.pollLast(DruidDataSource.java:1076)
	at com.alibaba.druid.pool.DruidDataSource.getConnectionInternal(DruidDataSource.java:756)
	at com.alibaba.druid.pool.DruidDataSource.getConnectionDirect(DruidDataSource.java:644)
	at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:4530)
	at com.alibaba.druid.filter.stat.StatFilter.dataSource_getConnection(StatFilter.java:659)
	at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:4526)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:626)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:618)
	at com.sanyuan.dao.DBConnection.getConnection(DBConnection.java:267)
	at com.sanyuan.dao.DBAccess.setPreparedSQL(DBAccess.java:65)
	at com.clsoftware.sms.manager.SmsSenderLogManager.getTop1LogListByCondition(SmsSenderLogManager.java:641)
	at org.apache.jsp.superadmin.sms.autoCheckInfor_jsp._jspService(autoCheckInfor_jsp.java:72)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:413)
	at com.clsoftware.filter.MyFilterDispatcher.doFilter(MyFilterDispatcher.java:162)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:291)
	at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
	at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
	at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:776)
	at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:705)
	at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:898)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)
	at java.lang.Thread.run(Thread.java:619)

loopWaitCount 0, wait millis 60000  一看字面意思就是数据库有问题了....找了N久才发现不是数据库的问题...

原来用户用了数据库连接池,由于我们的诶个虚拟主机都有数据库并发的限制,用户把数据库连接池最大连接数设置为50 , 造成了数据库连接池不够用,通知用户,增加数据库连接池后,重启tomcat恢复正常!!