Oracle数据库中的更改对于某些查询不可见

Question

I have a large query which looks something like this:

SELECT stuff, CASE WHEN (some subselect) > 0 THEN 'value 1' 
         WHEN (another subselect) > 0 THEN 'value 2' 
         ELSE 'value 3' END AS status
FROM (yet another subselect) e 

It works great. But then, from Spring, trough JpaRepositories I make some changes which effect the some subselect part, but for some reason, these changes are not immediate. In other queries the changes are visible, I tried using several transnational mechanism in Spring, tried not using transaction at all, I'm using saveAndFlush on the repositories, without any luck.

But this delay also happened if I restarted the Tomcat server before the changes were visible. This delay is also visible from an external db manipulation program, so I'm guessing the problem is not with my application.

Can some kind of Oracle caches or transactions effect this? How can I purge, flush, commit them?

EDIT (for request in the comments):

In Java I only make basic changes

Java code

MyEntity myEntity = myEntityDao.findOne(someId);
myEntity.setProperty(newValue);
myEntityDao.saveAndFlush(myEntity);

Where myEntityDao looks something like

@Repository
public interface MyEntityDao extends JpaRepository<MyEntity, Integer> {
     //... other unrelated HQL query methods
}

Sorry I can't post anything more specific, but it's huge, and also, I just can't, for corporate reasons. Also note, that everything is working, but with a certain delay, between the modification and this one specific query. Other queries can see the changes immediately.

Answer 1

Most probable reasons are:
1) changes made in separate transaction and was not committed before query started.
Oracle doesn't allow to read not committed changes from other transactions.
And query returns consistent data to the moment of query start.
2) If you change transaction to "read only" or "serializable" then Oracle will return data consistent to transaction start. So changes made in another transaction need to be committed before your read only transaction started.