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

Question

有一个批处理作业如下所示：

@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，我偶尔会遇到以下错误。

ORA-01000: maximum open cursors exceeded

我决定责怪 doActualProcessing() 和 save() 方法，因为它们最终可能会在一次事务中创建数百个 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，多个其他事务用于处理和持久化。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，我都会得到：

Caused by: org.hibernate.HibernateException: illegally attempted to associate a proxy with two open Sessions

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

Answer 1

在我看来，问题在于您已经检索到顶级交易中的实体，虽然它们仍然与该交易相关联，但您尝试将它们（代理）传递给将在单独的处理中处理的方法交易。

我认为您可以尝试两种选择：

1) 在调用之前分离实体 processor.doProcess(entries, additional);:

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

然后内部事务尝试合并：

session.merge(entity);

2) 第二个选项是检索 ID 而不是 getEntriesToProcessWithLock 中的实体。然后您将传递不会导致代理问题的普通原始字段。然后，您将在内部事务中检索适当的实体。

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

HibernateTransactionManager @Transactional(propagation=REQUIRES_NEW) cannot open 2 sessions

java

spring

hibernate

jpa

transactional