Question

我遇到以下错误，我很难调试此问题的来源。我有以下两个会议工厂：

<bean id="sessionFactory1"
      class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.connection.driver_class">${db.driver}</prop>
            <prop key="hibernate.connection.url">${db.jdbcurl2}</prop>
            <prop key="hibernate.connection.username">${db.username2}</prop>
            <prop key="hibernate.connection.password">${db.password2}</prop>
            <prop key="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider
            </prop>
            <prop key="hibernate.c3p0.min_size">1</prop>
            <prop key="hibernate.c3p0.max_size">6</prop>
            <prop key="hibernate.c3p0.maxIdleTime">3000</prop>
            <prop key="hibernate.c3p0.timeout">5000</prop>
            <prop key="hibernate.c3p0.max_statements">50</prop>
            <prop key="hibernate.c3p0.idle_test_period">3000</prop>
            <prop key="hibernate.c3p0.preferredTestQuery">SELECT 1</prop>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
            <prop key="hibernate.show_sql" >false</prop>
            <prop key="hibernate.format_sql" >false</prop>
            <prop key="hibernate.hbm2ddl.auto" >update</prop>
        </props>
    </property>
</bean>

<bean id="sessionFactory2"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean" primary="true">
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.connection.driver_class">${db.driver}</prop>
                <prop key="hibernate.connection.url">${db.jdbcurl}</prop>
                <prop key="hibernate.connection.username">${db.username}</prop>
                <prop key="hibernate.connection.password">${db.password}</prop>
                <prop key="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider
                </prop>
                <prop key="hibernate.c3p0.min_size">1</prop>
                <prop key="hibernate.c3p0.max_size">6</prop>
                <prop key="hibernate.c3p0.maxIdleTime">3000</prop>
                <prop key="hibernate.c3p0.timeout">5000</prop>
                <prop key="hibernate.c3p0.max_statements">50</prop>
                <prop key="hibernate.c3p0.idle_test_period">3000</prop>
                <prop key="hibernate.c3p0.preferredTestQuery">SELECT 1</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
                <prop key="hibernate.show_sql" >false</prop>
                <prop key="hibernate.format_sql" >false</prop>
                <prop key="hibernate.hbm2ddl.auto" >update</prop>
            </props>
        </property>
    </bean>

以下连接数据：

db.driver = com.mysql.jdbc.Driver

hibernate.dialect = org.hibernate.dialect.MySQLDialect

db.jdbcurl = JDBC：MySQL的：//本地主机：3306 / XXXXautoReconnect =真安培; allowMultiQueries =真   db.username = XXXX

db.password = YYYY

db.jdbcurl2 = JDBC：MySQL的：//XXXXX-cluster.XXXXXXXX.eu-west-2.rds.amazonaws.com：3306 / XXXX autoReconnect的=真安培; allowMultiQueries =真

db.username2 = XXXX

db.password2 = YYYY

这是我从日志中得到的错误消息：

    2017-10-30 12:16:25 WARN  ThreadPoolAsynchronousRunner:743 - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@6cf38f72 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
2017-10-30 12:16:25 WARN  ThreadPoolAsynchronousRunner:759 - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@6cf38f72 -- APPARENT DEADLOCK!!! Complete Status: 
    Managed Threads: 3
    Active Threads: 3
    Active Tasks: 
        com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@5371f5ab
            on thread: C3P0PooledConnectionPoolManager[identityToken->1bqsmig9ruavayon79lc0|319cb4da]-HelperThread-#0
        com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@12e0b3c5
            on thread: C3P0PooledConnectionPoolManager[identityToken->1bqsmig9ruavayon79lc0|319cb4da]-HelperThread-#2
        com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@2b726e6f
            on thread: C3P0PooledConnectionPoolManager[identityToken->1bqsmig9ruavayon79lc0|319cb4da]-HelperThread-#1
    Pending Tasks: 
        com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@432689e8
Pool thread stack traces:
    Thread[C3P0PooledConnectionPoolManager[identityToken->1bqsmig9ruavayon79lc0|319cb4da]-HelperThread-#0,5,RMI Runtime]
        java.net.PlainSocketImpl.socketConnect(Native Method)
        java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
        java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
        java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)

我尝试将c3p0.max_statements设置为0以及其他许多功能都没有，所以如果您知道如何解决此问题，我正在寻求您的帮助。

我认为值得一提的是，当我在本地使用2个数据源时，一切都工作正常。我创建一个新的RDS实例并将jdbcurl url更改为rds的那一刻，我得到了上面提到的错误消息..

提前谢谢！

Answer 1

问题是你的RDS数据库的尝试是挂起的 - 既没有失败，也没有成功，提供和异常，只是挂起。当我没有正确配置我的实例以接受来自客户端的连接时，我在AWS上经历过Connection挂起。这可能是你的问题。

测试和调试的一种方法是使用简单的测试程序，例如

import java.sql.*;

public static void main(String[] argv) {
  try {
    DriverManager.getConnection("dbc:mysql://XXXXX-cluster.XXXXXXXX.eu-west-2.rds.amazonaws.com:3306/XXXX?autoReconnect=true&allowMultiQueries=true","XXXX","YYYY").close();
    System.out.println("Successfully acquired and closed a Connection.");
  }
  catch ( Exception e ) {
    e.printStackTrace();
  }
}

如果您可以访问某种类型的REPL，那么只需尝试

    DriverManager.getConnection("dbc:mysql://XXXXX-cluster.XXXXXXXX.eu-west-2.rds.amazonaws.com:3306/XXXX?autoReconnect=true&allowMultiQueries=true","XXXX","YYYY").close();

如果从您打算运行应用程序的机器成功，那么您的应用程序可能也是如此。

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1 个答案: