Hibernate version: 3.2
MySQL 5.0
Using Annotations to define data mapping

I have a couple of entities that have LOB properties that can be very large (one BLOB and one CLOB). I expected that the data for these properties would not be initialized with the rest of the properties, but that a reference to the data would be available so it could be retrieved when I was ready for it (using a java.sql.Blob or java.sql.Clob instance). However, I am seeing that the LOB data is fully initialized with the rest of the properties.

In reading the description of LOB handling in the book "Java Persistence with Hibernate", they say that these properties are not lazily initialized unless the @Lob annotation is used, and the data type is the java.sql.Clob type. This is how I have my property defined, but it still is not using lazy initialization. Here is the definition of my Clob property within my entity.

@Lob
@Column(name="TEST_CASE_EXECUTION_LOG", length=1048574)
public Clob getTestCaseExecutionLog()
{
return m_testCaseExecutionLog;
}

When using this property, I have tried setting it with a javax.sql.rowset.serial.SerialClob as well as using a Clob created using Hibernate.createClob(). Same behavior with either one.

Can anyone give me any ideas as to how to force these properties to behave the way I want them to? I am getting out of memory exceptions due to the eager loading of all of these Lobs.

Thanks in advance,
Jay

Hi Jay,

I think I found documentation for lazy properties (different from lazy associations):

http://www.hibernate.org/hib_docs/v3/re ... properties

If I understand the above correctly, there are 2 ways to solve this:
1) setting up buildtime bytecode instrumentation
2) using projection of the class <-- preferred?

3) creating a class wrapper around the blob(s)/clob(s) to obfuscate the relation and allow for easier lazy loading <-- not elegant?

I have a similar problem, except I do not run out of memory. Page navigation is just (incredibly) slower.

I would be curious to know which route you decide to take...

Hope this helps,

-- Dan