[Hibernate] serialized/deserialized criteria and query cache issue

[Mario I. <ma...@op...>]

Hi!

I already posted on the user list, but I looks like due to the massive
posts it got lost.
I took many time to think about this issue, and so I'll post it to your
dev list as I'll eventually try to create a patch for it.

Hibernate version:
3.2.0 rc1

A serialized/deserialized DetachedCriteria do not work correctly with
the query cache.
The problem is the ResultTransformer in QueryKey.

In CriteraImpl the resultTransformer will be set to Criteria.ROOT_ENTITY.
This makes it down into the QueryKey.

After serialize/deserialize the instance of resultTransformer in
CriteriaImpl has changed (not that a surprise ;-) ) and thus - in the
end - the QueryKey changed.

Subsequent lookup in the query-cache will no longer work.
The query will be executed again and put int the query-cache.
The cache grows - every lookup failes.

I think every ResultTransformer used as singleton should implement some
custom deserialization code so that always the same instance will be
returned - this is one solution.

What solution do you prefer? Just in case I manage to send a patch.

Thanks!
Ciao,
Mario