Hibernate xConnectionAge被设置为14400，根据文档，这是以秒（而不是毫秒）为单位的，因此是240分钟。我一定会尝试打开日志记录。问题是它会打开和关闭大量连接，因此很难隔离发生连接的位置。尤其是在负载下。 WARN [2011-03-07 17

xConnectionAge被设置为14400，根据文档，这是以秒（而不是毫秒）为单位的，因此是240分钟。我一定会尝试打开日志记录。问题是它会打开和关闭大量连接，因此很难隔离发生连接的位置。尤其是在负载下。

    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)

 <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;

 <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>

$ msql -u [user] -p

$ show variables where Variable_name='max_connections';