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,我偶尔会收到以下错误。
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个事务中创建数百个 blob。
明显的出路似乎是将处理分成多个事务: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:暂停当前事务并启动新事务?
最佳答案
在我看来,问题在于您已经检索了顶部事务中的实体,并且当它们仍然与该事务相关联时,您尝试将它们(代理)传递给将在单独的事务中处理的方法。
我认为你可以尝试两种选择:
1) 在调用之前分离实体 processor.doProcess(entries, extra);
:
session.evict(entity); // loop through the list and do this
然后在内部事务中尝试合并:
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,您将检索内部事务内的正确实体。
关于java - HibernateTransactionManager @Transactional(propagation=REQUIRES_NEW) 无法打开 2 个 session ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46363095/