9
我使用c3p0作为连接池运行连接到MySQL设置的Spring/Hibernate。由于某些奇怪的原因，当系统负载不足时（当然），它会断开连接。用完数据库连接！
该网站是相当稳定，直到我们开始达到一个新的水平（超过100个并发用户）。此时数据库将会融化（挂住CPU）。我的第一个行动是通过广泛的缓存和优化查询等来提高性能的应用程序。
现在它会间歇性地耗尽连接。它似乎甚至不依赖于负载。更多的时间，这让我觉得这是一个泄漏，但对于我的生活，我无法弄清楚它会来自哪里。
WARN [2011-03-07 17:19:42,409] [TP-Processor38] (JDBCExceptionReporter.java:100) - SQL Error: 0, SQLState: null
ERROR [2011-03-07 17:19:42,409] [TP-Processor38] (JDBCExceptionReporter.java:101) - An attempt by a client to checkout a Connection has timed out.
ERROR [2011-03-07 17:19:42,410] [TP-Processor38] (HttpHeadFilter.java:46) - There was a problem passing thru filter:/is-this-guy-crazy-or-just-a-huge-dancing-with-the-stars-fan
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.exception.GenericJDBCException: could not execute query
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:659)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:552)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
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.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:343)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
Caused by: java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:65)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:527)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
这里是我的配置：
<bean id="dataSource" class="org.springframework.jdbc.datasource.LazyConnectionDataSourceProxy">
<property name="targetDataSource" ref="rootDataSource" />
</bean>
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="mappingLocations" value="classpath:hibernate-mapping.xml" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.connection.provider_class">net.sf.hibernate.connection.C3P0ConnectionProvider</prop>
<prop key="hibernate.dialect">${hibernate.dialect}</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.cache.use_second_level_cache">true</prop>
<prop key="hibernate.cache.use_query_cache">true</prop>
<prop key="hibernate.cache.generate_statistics">true</prop>
<prop key="hibernate.cache.provider_class">net.sf.ehcache.hibernate.EhCacheProvider</prop>
<prop key="hibernate.generate_statistics">${hibernate.generate_statistics}</prop>
<prop key="hibernate.connection.zeroDateTimeBehavior">convertToNull</prop>
<prop key="hibernate.bytecode.use_reflection_optimizer">${hibernate.bytecode.use_reflection_optimizer}</prop>
<!--<prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>-->
<prop key="hibernate.jdbc.batch_size">${hibernate.jdbc.batch_size}</prop>
<!--Actually, it seems the following property affects batch size (or explicit per relationship in the mapping)-->
<!--<prop key="hibernate.default_batch_fetch_size">${hibernate.jdbc.batch_size}</prop>-->
</props>
</property>
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="rootDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driver}" />
<property name="jdbcUrl" value="${jdbc.url}" />
<property name="user" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
<property name="initialPoolSize" value="20" />
<property name="maxPoolSize" value="200" />
<property name="checkoutTimeout" value="30000" />
<property name="maxStatements" value="180" />
<property name="minPoolSize">
<value>${hibernate.c3p0.minPoolSize}</value>
</property>
<property name="acquireRetryAttempts">
<value>${hibernate.c3p0.acquireRetryAttempts}</value>
</property>
<property name="acquireIncrement">
<value>${hibernate.c3p0.acquireIncrement}</value>
</property>
<property name="idleConnectionTestPeriod">
<value>${hibernate.c3p0.idleConnectionTestPeriod}</value>
</property>
<property name="maxIdleTime">
<value>${hibernate.c3p0.maxIdleTime}</value>
</property>
<property name="maxIdleTimeExcessConnections">
<value>${hibernate.c3p0.maxIdleTimeExcessConnections}</value>
</property>
<property name="maxConnectionAge">
<value>${hibernate.c3p0.maxConnectionAge}</value>
</property>
<property name="preferredTestQuery">
<value>${hibernate.c3p0.preferredTestQuery}</value>
</property>
<property name="testConnectionOnCheckin">
<value>${hibernate.c3p0.testConnectionOnCheckin}</value>
</property>
<property name="numHelperThreads">
<value>${hibernate.c3p0.numHelperThreads}</value>
</property>
<property name="unreturnedConnectionTimeout">
<value>${hibernate.c3p0.unreturnedConnectionTimeout}</value>
</property>
<property name="debugUnreturnedConnectionStackTraces">
<value>${hibernate.c3p0.debugUnreturnedConnectionStackTraces}</value>
</property>
<property name="automaticTestTable">
<value>${hibernate.c3p0.automaticTestTable}</value>
</property>
</bean>
hibernate.c3p0.acquireIncrement=5
hibernate.c3p0.minPoolSize=20
hibernate.c3p0.acquireRetryAttempts=30
hibernate.c3p0.idleConnectionTestPeriod=3600
hibernate.c3p0.maxIdleTime=7200
hibernate.c3p0.maxIdleTimeExcessConnections=1800
hibernate.c3p0.maxConnectionAge=14400
hibernate.c3p0.preferredTestQuery=select 1;
hibernate.c3p0.testConnectionOnCheckin=false
hibernate.c3p0.numHelperThreads=6
hibernate.c3p0.unreturnedConnectionTimeout=0
hibernate.c3p0.debugUnreturnedConnectionStackTraces=true
hibernate.c3p0.automaticTestTable=test_connection;
我正在运行的OpenSessionInViewInterceptor应关闭连接：
<bean id="openSessionInViewInterceptor" class="org.springframework.orm.hibernate3.support.OpenSessionInViewInterceptor">
<property name="sessionFactory">
<ref bean="sessionFactory" />
</property>
<property name="flushModeName">
<value>FLUSH_AUTO</value>
</property>
</bean>
我也利用弹簧注解@Transactional因为我重用我非网页前端代码中的服务。
这里确实只有两个选项，它在完成时不会释放连接。或者它正在闲聊聊天室，就像它试图穿上裤子一样。 如果任何人有任何想法，我将不胜感激 THX
跟进：最终事实证明，我被泄露，由于使用的OpenSessionInViewInterceptor连接。我的弹簧安全性作为一个过滤器运行，所以它将连接到数据库并且从不关闭它们。解决的办法是将OpenSessionInViewInterceptor移动到OpenSessionInViewFilter。
我maxConnectionAge设置为14400根据文档以秒为单位（不MS），所以这将是240分钟。我绝对会尝试开启日志记录。问题在于它打开并关闭了一个TON连接，因此隔离它发生的位置很困难。特别是在负载下。 – matsientst 2011-03-08 18:16:38