C3p0 getConnection() исключает исключение: ResourcePool не смог получить ресурс из своего основного factory или источника

у нас есть конфигурация [Hibernate + c3p0 + MySQL] для нашего проекта. Мы сталкиваемся со следующим исключением:

com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.

    at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319) ~[c3p0-0.9.1.2.jar:0.9.1.2]

    at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557) ~[c3p0-0.9.1.2.jar:0.9.1.2]

    at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477) ~[c3p0-0.9.1.2.jar:0.9.1.2]

    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525) ~[c3p0-0.9.1.2.jar:0.9.1.2]

Wrapped by: java.sql.SQLException: Connections could not be acquired from the underlying database!

    at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106) ~[c3p0-0.9.1.2.jar:0.9.1.2]

    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529) ~[c3p0-0.9.1.2.jar:0.9.1.2]

    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128) ~[c3p0-0.9.1.2.jar:0.9.1.2]

    at org.hibernate.service.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:141) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:276) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:297) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

Wrapped by: org.hibernate.exception.GenericJDBCException: Could not open connection

    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:52) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:304) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:169) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1263) ~[hibernate-core-4.0.1.Final.jar:4.0.1.Final]

    at org.springframework.orm.hibernate4.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:399) ~[spring-orm-3.1.2.RELEASE.jar:3.1.2.RELEASE]

Wrapped by: org.springframework.transaction.CannotCreateTransactionException: Could not open Hibernate Session for transaction; nested exception is org.hibernate.exception.GenericJDBCException: Could not open connection

    at org.springframework.orm.hibernate4.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:440) ~[spring-orm-3.1.2.RELEASE.jar:3.1.2.RELEASE]

    at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE]

    at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:336) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE]

    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:105) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE]

    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE]

    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE]

    at $Proxy28.messageExists(Unknown Source) ~[na:na]

Наша конфигурация c3p0:

<bean id="provDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
…
        <property name="acquireIncrement" value="1" />
        <property name="idleConnectionTestPeriod" value="100"/>
        <property name="minPoolSize" value="5" />
        <property name="maxPoolSize" value="50" />
        <property name="maxIdleTime" value="1800" />
</bean>

Обратите внимание, что у нас также есть другой подобный источник данных c3p0, настроенный поверх этого экземпляра MySQL.

Может ли кто-нибудь дать мне несколько предложений о том, как отладить это?

Ответ 1

Хотя я не ответил на ваш вопрос, я не хотел добавлять код в комментарии, так как код в комментариях нечитабелен.

Вот пример конфигурации MySQL с C3P0 из моего проекта. обратите внимание на все дополнительные параметры, чтобы убедиться, что соединения не умирают. (В конце концов я пошел с Postgres, потому что он не убивал мои соединения и был более стабильным вообще, а также повторять проверки с помощью select 1; не очень эффективно)

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
     destroy-method="close">
  <property name="driverClass" value="${jdbc.driverClassName}"/>
  <property name="jdbcUrl" value="${jdbc.url}"/>
  <property name="properties">
    <props>
        <prop key="c3p0.minPoolSize">0</prop>
        <prop key="hc3p0.maxPoolSize">1000</prop>
        <prop key="hc3p0.timeout">3000</prop>
        <prop key="c3p0.acquire_increment">10</prop>
        <prop key="c3p0.max_statement">50</prop>

        <prop key="hibernate.c3p0.idle_test_period">60</prop>
        <prop key="c3p0.preferredTestQuery">SELECT 1;</prop>
        <prop key="hibernate.c3p0.testConnectionOnCheckout">false</prop>
        <prop key="user">${jdbc.username}</prop>
        <prop key="password">${jdbc.password}</prop>
    </props>
  </property>
</bean>