休眠保存复杂实体

Question

I have a relatively complex entity. Something like this:

@Entity
public class MyEntity {

/// some fields
///...

@OneToMany(/*cascade = CascadeType.ALL, */fetch = FetchType.EAGER)
@Fetch(FetchMode.SELECT)
@Cascade({CascadeType.ALL})
protected Set<ParameterValue> parameterValues 

//...
}

@Entity
public class ParameterValue {

// ...
 @ManyToOne(fetch = FetchType.EAGER)
 @Cascade({org.hibernate.annotations.CascadeType.MERGE,     org.hibernate.annotations.CascadeType.SAVE_UPDATE, org.hibernate.annotations.CascadeType.REFRESH})
 private Parameter  parameter

}

MyEntity has String id, ParameterValue has generated long Id and Parameter has string id

My Entity has parameter values, each of whose has parameter, which is shared among other parameter values from different entities

Parameter is abstract class with different implementations

My problem is that when I call hibernate session saveOrUpdate for such objects 1) it is very slow 2) sometimes I receive org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [com.xxx.entities.content.EnumParameter#-1672482954]

What is correct way to save/update such entities ?

I inherited the schema from previous developer, so if it is required to simplify saving, I can change it

Answer 1

well, transitioning to long unique IDs that are proper primary key (unique, indexed) in database can speed up updates significantly.

depending on what you're updating, getting rid of eager fetch is another way of speeding things up - maybe you only need to update some ParamValue in some MyEntity ? Retrieve just that ParamValue and store it after modification ( select p from ParamValue p where p.entity=:entity ).

It really depends on what your code actually does, but those two things (lazy loading and proper unique keys) will speed things up - though lazy loading might need reviewing some code.