I have the following relationship:



the item table has a foreign key category_id. In the java, Item has a field category, and Category has a SortedSet field items. Here are the relevant mappings:





I'm also using ehcache. Here are those settings:



When I set or unset a item's category, I always set both ends of the relationship, setting the item's field and adding the item to the category's set.

Everything seems to work just fine, as it does for the numerous other many-to-one relationships that I have that are very similar to this one. However, I am experiencing mysterious data loss ... the relationship is being reset to null a certain amount of time after it is set. It is possible that it is being reset around the 4 hour timeToIdleSeconds threshold, but it certainly happens before the 6 hour timeToLiveSeconds threshold.

Just to summarize what the user experience is:
1. user associates item with category using the web tool
2. user continues working, all the time the tool indicates that the relationship is set.
3. user comes back after a few hours, or the next day, and relationship is not set.

Does anyone have any ideas what this could possibly be?

I'm using Hibernate 2.1 and the ehcache that came with it.

Thanks,

1) show the whole mapping ... I don't even see any <cache> element in the set mapping!
2) what happens when you use a different cache provider (say, HashtableCacheProvider)

Here's an update on this issue. I'm still not sure if it's a bug or somehow that I'm not using Hibernate right.

Here are some things I did and how they affected the problem:

- updated to Hibernate 2.1.1, no change
- updated to ehcache 0.7, no change
- turned off caching, behavior fixed
- changed the one-to-many inverse="false" to ="true"
- turned cache back on, behavior still fixed

I happened to notice that this was one of just three one-to-many inverse="false" relationships in the whole application and the only one that was used with any frequency. That gave me a clue as the the source of the problem. I read up on what inverse really means in the one-to-many relationship, but couldn't find anything that looked wrong in the code. Every time I set a relationship I set it from both directions since these objects live a long time in the cache and the relationship has to be navigable from both ends.

So my hunch is that this is an issue with ehcache + one-to-many inverse="false". The problem showed up only after switching from JCS to ehcache with 2.1 final.

Gavin, not sure what you mean about not seeing a <cache> element. I configure the cache in the hibernate.cfg.xml file, from which I included the relevant snippets.

No you didn't. There are no snippets from .cfg.xml. I need them.


Does the behavior change depending upon the timeouts you set in EHCache? What happens if you completely disable eviction in EHCache?

so sorry, here are the cache settings, not too exciting:



Yes, when I reduced timeToIdleSeconds and timeToLiveSeconds, the error occurred more quickly and we were better able to debug since the period was reduced.

As for disabling eviction, I didn't try that.

OK, would you give me a very simple test case (just one association) to reproduce this (submit it to JIRA).