internal multiple references from different rows to a single BLOB/CLOB stream leads to various errors when second reference used.

Derby + Hibernate JPA 3.2.1 problem on entity with Blob/Clob

Hi,

I'm using Derby in Client - Server mode with Hibernate JPA EJB 3.0.
When a query on an entity containing a Clob and some joins on other entites is executed, an exception with the following message is thrown:
XJ073: The data in this BLOB or CLOB is no longer available. The BLOB/CLOB's transaction may be committed, or its connection is closed.

This problem occurs when the property "hibernate.max_fetch_depth" is greater than 0.
When hibernate.max_fetch_depth=0, the query works.

If Derby is configured in embedded mode, the query works independently of the value of hibernate.max_fetch_depth.

On the Hibernate's documentation, the advised value of hibernate.max_fetch_depth is 3.
Could you explain me if I made something wrong ?

Thank you.
Stephane