c3p0 getConnection() genera un'eccezione: un ResourcePool non può acquisire una risorsa dal suo factory o origine primaria

Question

abbiamo una configurazione [Hibernate + c3p0 + MySQL] per il nostro progetto. Stiamo colpendo la seguente eccezione:

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] 

nostro c3p0 config:

<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> 

Nota che abbiamo anche un altro simile c3p0 origine dati configurata in cima a questa istanza di MySQL.

Qualcuno può darmi qualche suggerimento su come eseguire il debug di questo?

Answer 1

Sebbene non risponda rigorosamente alla tua domanda, non ho voluto aggiungere codice nei commenti poiché il codice nei commenti è illeggibile.

Ecco un esempio di configurazione di MySQL con C3P0 dal mio progetto. annota tutti i parametri extra per assicurarti che le connessioni non muoiano. (Alla fine sono andato con Postgres, perché non ha ucciso i miei collegamenti ed era più stabile in generale, anche di dover ripetere il test connessioni con selezionare 1; non è molto efficiente)

<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>