Question

我在Java / Wicket中使用Hibernate 4.1.1和Spring 3.1.1以及Postgres 9.2创建了一个Web应用程序。我还使用spring transaction api和c3p0连接池。

我的问题是没有释放可用的连接，并且在执行了由gui引起的一些select语句后，我得到以下异常

com.mchange.v2.resourcepool.CannotAcquireResourceException：A ResourcePool无法从其主要工厂获取资源资源。执行SELECT * FROM pg_stat_activity;表明存在是这样的许多空闲查询：SELECT NULL AS TABLE_CAT, n.nspname AS TABLE_SCHEM, c.relname AS TABLE_NAME, CASE n.nspname ~ '^pg_' OR n.nspname = 'information_schema' WHEN true THEN CASE WHEN n.nspname = 'pg_catalog' OR n.nspname = 'information_schema' THEN CASE c.relkind WHEN 'r' THEN 'SYSTEM TABLE' WHEN 'v' THEN 'SYSTEM VIEW' WHEN 'i' THEN 'SYSTEM INDEX' ELSE NULL END WHEN n.nspname = 'pg_toast' THEN CASE c.relkind WHEN 'r' THEN 'SYSTEM TOAST TABLE' WHEN 'i' THEN 'SYSTEM TOAST INDEX' ELSE NULL END ELSE CASE c.relkind WHEN 'r' THEN 'TEMPORARY TABLE' WHEN 'i' THEN 'TEMPORARY INDEX' WHEN 'S' THEN 'TEMPORARY SEQUENCE' WHEN 'v' THEN 'TEMPORARY VIEW' ELSE NULL END END WHEN false THEN CASE c.relkind WHEN 'r' THEN 'TABLE' WHEN 'i' THEN 'INDEX' WHEN 'S' THEN 'SEQUENCE' WHEN 'v' THEN 'VIEW' WHEN 'c' THEN 'TYPE' ELSE NULL END ELSE NULL END AS TABLE_TYPE, d.description AS REMARKS FROM pg_catalog.pg_namespace n, pg_catalog.pg_class c LEFT JOIN pg_catalog.pg_description d ON (c.oid = d.objoid AND d.ob

这是我的applicationContext.xml：

 <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:util="http://www.springframework.org/schema/util"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:lang="http://www.springframework.org/schema/lang"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                           http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd
                           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
                           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
                           http://www.springframework.org/schema/lang http://www.springframework.org/schema/lang/spring-lang-3.1.xsd"
       default-autowire="byName">


    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
                    destroy-method="close">
           <property name="driverClass" value="org.postgresql.Driver"/>
           <property name="jdbcUrl" value="jdbc:postgresql://localhost:5432/mydatabase"/>
           <property name="user" value="myuser"/>
           <property name="password" value="mypassword"/>

           <!-- configuration pool via c3p0 -->
           <property name="initialPoolSize" value="3"/>
           <property name="minPoolSize" value="3"/>
           <property name="maxPoolSize" value="30"/>
           <property name="idleConnectionTestPeriod" value="600"/>
           <property name="maxIdleTime" value="0"/>
           <property name="maxStatements" value="0"/>
           <property name="maxStatementsPerConnection" value="0"/>
           <property name="acquireIncrement" value="1"/>
           <property name="acquireRetryAttempts" value="3"/>
           <property name="acquireRetryDelay" value="1000"/>
           <property name="autoCommitOnClose" value="false"/>
           <property name="maxConnectionAge" value="14400"/>
           <property name="forceIgnoreUnresolvedTransactions" value="false"/>
           <property name="numHelperThreads" value="20"/>
           <property name="testConnectionOnCheckin" value="false"/>
           <property name="testConnectionOnCheckout" value="false"/>
           <property name="maxAdministrativeTaskTime" value="0"/>
           <property name="debugUnreturnedConnectionStackTraces" value="false"/>
           <property name="maxIdleTimeExcessConnections" value="0"/>
           <property name="breakAfterAcquireFailure" value="false"/>
           <property name="checkoutTimeout" value="0"/>
           <property name="unreturnedConnectionTimeout" value="0"/>
           <property name="usesTraditionalReflectiveProxies" value="false"/>
      </bean>

    <bean id="exampleDao"
        class="com.mycompany.persistence.hibernate.daoimpl.ExampleDaoImpl">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>


    <bean id="sessionFactory"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
      <property name="dataSource" ref="dataSource" />
      <property name="annotatedClasses">
        <list>
            <value>com.mycompany.model.Example</value>
        </list>
      </property>

      <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</prop>
            <prop key="hibernate.show_sql">true</prop>
            <prop key="hibernate.format_sql">true</prop>
            <prop key="hibernate.current_session_context_class">org.springframework.orm.hibernate4.SpringSessionContext</prop>
            <prop key="hibernate.auto_close_session">true</prop>
            <prop key="hibernate.c3p0.maxSize">30</prop>
            <prop key="hibernate.c3p0.minSize">1</prop>
            <prop key="hibernate.c3p0.acquireIncrement">1</prop>
            <prop key="hibernate.c3p0.idleTestPeriod">300</prop>
            <prop key="hibernate.c3p0.timeout">1800</prop>
            <prop key="hibernate.c3p0.maxStatements">0</prop>
            <prop key="hibernate.c3p0.unreturnedConnectionTimeout">30</prop> 
            <prop key="hibernate.c3p0.debugUnreturnedConnectionStackTraces">true</prop>
            <prop key="hibernate.c3p0.checkoutTimeout">0</prop>
            <prop key="hibernate.c3p0.preferredTestQuery">SELECT * FROM dual</prop>
        </props>
      </property>
    </bean>

   <!-- Transaction Management -->
   <tx:annotation-driven transaction-manager="transactionManager"/>
    <bean id="transactionManager"
    class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>
</beans>

配置是否正确？

我从类中检索数据的类是这样的：

@Repository
public class ExampleDaoImpl extends BaseDaoImpl implements ExampleDao {
...
    @Override
    @Transactional(readOnly=true)
    public List<Example> findExampleByCompanyAndType(Company company,
            int type) {
        return sessionFactory.getCurrentSession()
                .createCriteria(Example.class)
                .add(Restrictions.eq("company.companyId",
                        company.getCompanyId()))
                .add(Restrictions.eq("type", type)).list();

    }
...
}

Answer 1

PostgreSQL没有实现'双重'，所以你可能想要那里的SELECT 1，用于测试查询。我不知道这是否能解决您的问题，但它应该有助于容器更好地管理自己。

Postgres空闲连接：CannotAcquireResourceException

1 个答案: