JPA - 数据库维护导致死锁/挂起恢复？

Question

我对JPA相对较新，并且继承了＃34;这段代码，但我有一个似乎是死锁/挂起的问题。只有当我们的数据库在一定时间内（维护）不可用时才会发生这种情况。可能有10个单独的线程/处理器，基本上有一个点击数据库异常，它会循环并尝试从中恢复，其他线程似乎挂起数天

我已经搜索了但如果这是重复，我无法找到我正在寻找的东西。

isCommunicationFailure（）报告数据库错误并重新启动进程

主题＃1 内部异常：java.sql.SQLException：Io异常：断开的pipeError代码：17002 at com.SomeClass.isCommunicationFailure

主题＃2 信息：坚持...... 2015年2月14日下午7:55:23 com.SomeClass.transitionUncachedToState 信息：即将提交工作状态.... 2015年2月15日下午2:04:35 com.SomeClass.JPAJobStore＆lt; --- 这是我们重新启动流程的地方，因为它没有移动。

我需要设置某些OPTIMISTIC对象吗？锁定会超时吗？还是有其他一些基本的处理方法吗？

我正在使用Oracle DB后端。下面的persistence.xml（我已经手动更改了这个问题的一些类名是通用的）。

提前致谢...：）

public boolean transitionUncachedToState(Job job, String zId)
throws RAAException
{
    boolean                                 result = false;
    String                                  jobReqId = job.getJobRequestId();
    Query                                   query;
    Job              jpaJob;        
    long starttime, stoptime;
    starttime = DateUtil.getCurrentUtcTime();
    try {
        query = em.createNamedQuery("getUnzippedJobUsingJobReqId");
    query.setHint("javax.persistence.query.timeout", 30000);
        query.setParameter("jobReqId", jobReqId);
        jpaJob = (Job)query.getSingleResult();
        em.refresh(jpaJob);
        stoptime = DateUtil.getCurrentUtcTime();
        logger.info("get jpaJob="+jpaJob.toString().substring(0, 512)
            + ", time in miliseconds " + (stoptime-starttime));
        starttime = stoptime;
    } 
    catch(NoResultException ex) 
    {
        logger.info("job " + jobReqId + " can not be locked.");
        return result;
    }

    //jpaReportCacheState = jpaJob.getJobDetails().getReportCacheState();
    JobDetails jpaJobDetails = jpaJob.getJobDetails();
    em.refresh(jpaJobDetails);
    ProcessingState jpaState = jpaJobDetails.getProcessingState();
    em.refresh(jpaState);
    logger.info("Job.Z_STATE_UNPROCESSED="
        + Job.Z_STATE_UNPROCESSED
        + ", jpaState.getState()="+jpaState.getState());
    if(Job.Z_STATE_UNPROCESSED.equals(jpaState.getState()))
    {
                    // Set Job's report cache state to CACHING
        job.setStartTime(DateUtil.getCurrentUtcTime());
        job.setState(Job.Z_STATE_ZIPPING);
        job.setId(zId);
        job.setProcessingAttempts(job.getProcessingAttempts() + 1);
         try {
            logger.info(job.getId());
            em.getTransaction().begin();
            jpaState.setState(job.getState());
            jpaState.setStartProcessingTime(new Date(job.getStartTime()));
            jpaJob.setId(job.getId());
            logger.info("Persisting...");

    em.persist(jpaState);
            em.persist(jpaJob);
    logger.info("About to commit job state....");
            em.getTransaction().commit();
    em.clear();
            stoptime = DateUtil.getCurrentUtcTime(); 
            logger.info("Successful lock on job " + jobReqId
                    + ", JPA update time in miliseconds " + (stoptime-starttime));
            result = true;
        } 
        catch(Exception ex) {
            if(isCommunicationFailure(ex)) {
                result = transitionUncachedToState(job, zId);
            }
        }
    }
    return result;
}



   <persistence xmlns="http://java.sun.com/xml/ns/persistence"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/persistence persistence_1_0.xsd"
         version="1.0">

<persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
    <provider>
       oracle.toplink.essentials.PersistenceProvider
    </provider>

    <class>com.SomeClass.Job</class>


    <properties>
        <property name  ="toplink.target-database" value="Oracle"/>

        <property name="user" value="somthing"/>
        <property name="password" value="somthing123"/>    

        <property name="toplink.logging.level" value="SEVERE"/>
        <property name="toplink.logging.exceptions" value="true"/>

        <!--<property name="toplink.jdbc.driver" value="com.mysql.jdbc.Driver"/>-->
        <property name="toplink.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
        <property name="toplink.jdbc.url" value="jdbc:oracle:thin:@someurl"/>
        <property name="toplink.jdbc.user" value="user"/>
        <property name="toplink.jdbc.password" value="pass"/>

        <property name="toplink.jdbc.bind-parameters" value="true"/>
        <property name="toplink.cache.size.default" value="5000"/>
        <property name="toplink.cache.shared.ContainerEntry" value="false"/>
        <property name="toplink.cache.shared.Hosts" value="false"/>
        <property name="toplink.cache.shared.default" value="true"/>
        <property name="toplink.weaving" value="true"/>


        <property name="toplink.jdbc.read-connections.max" value="1"/>
        <property name="toplink.jdbc.read-connections.min" value="1"/>
        <property name="toplink.jdbc.write-connections.max" value="1"/>
        <property name="toplink.jdbc.write-connections.min" value="1"/>

        <property name="toplink.cache.type.Order" value="Weak"/>
    </properties>
</persistence-unit>