Question

有一个批处理作业看起来像这样：

@Transactional
public void myBatchJob() {
    // retrieves thousands of entries and locks them 
    // to prevent other jobs from touthing this dataset
    entries = getEntriesToProcessWithLock(); 
    additional = doPrepWork(); // interacts with DB
    processor = applicationContext.getBean(getClass());
    while (!entries.isEmpty()) {
        result = doActualProcessing(entries, additional); // takes as many entries as it needs; removes them from collection afterwards
        resultDao.save(result);
    }
}

但是，如果entries集合足够大，我偶尔会收到以下错误。

ORA-01000：超出最大打开游标数

我决定责怪doActualProcessing()和save()方法，因为它们最终会在一次交易中创建数百个blob。

显而易见的出路似乎是将处理拆分为多个事务：一个用于获取和锁定条目，另一个用于处理和持久化。像这样：

@Transactional
public void myBatchJob() {
    // retrieves thousands of entries and locks them 
    // to prevent other jobs from touthing this dataset
    entries = getEntriesToProcessWithLock(); 
    additional = doPrepWork(); // interacts with DB
    processor = applicationContext.getBean(getClass());
    while (!entries.isEmpty()) {
        processor.doProcess(entries, additional);
    }
}

@Transactional(propagation=REQUIRES_NEW)
public void doProcess(entries, additional) {
    result = doActualProcessing(entries, additional); // takes as many entries as it needs; removes them from collection afterwards
    resultDao.save(result);
}

现在每当调用doProcess时我都会：

引起：org.hibernate.HibernateException：非法尝试将代理与两个打开的会话相关联

如何让HibernateTransactionManager执行REQUIRES_NEW javadoc建议的内容：暂停当前事务并开始新事务？

Answer 1

在我看来，问题在于您已检索到顶级事务中的实体，并且当它们仍与该事务关联时，您尝试将它们（代理）传递给将在单独事务中处理的方法。

我认为您可以尝试两种选择：

1）在假装processor.doProcess(entries, additional);之前分离实体：

session.evict(entity); // loop through the list and do this

然后在内部事务内部尝试合并：

session.merge(entity);

2）第二个选项是检索{而不是getEntriesToProcessWithLock中的实体。然后你将传递普通的原始字段，这些字段不会导致代理问题。然后，您将在内部事务中检索正确的实体。

HibernateTransactionManager @Transactional（propagation = REQUIRES_NEW）无法打开2个会话

1 个答案: