performance - Dynamic-update with JPA -

i surprised learn default hibernate behavior update of fields in object if single change made , merge called.

dynamic-update field allows configure alternative approach of updating changed field...

http://www.mkyong.com/hibernate/hibernate-dynamic-update-attribute-example/

i using jpa hibernate , tried add following

@javax.persistence.entity @org.hibernate.annotations.entity(dynamicinsert=true, dynamicupdate=true)  

to class (previously had jpa annotation)

anyway, i've been monitoring sql , unfortunately didn't change , i'm still seeing every field updated.

this java updates object...

    @transactional(readonly = false, propagation = propagation.requires_new)     public void setaccountstatusforuser(string username, accountstatus act){     user u = this.getuser(username);     u.setaccountstatus(act);     this.update(u); } 

and update method following:

    @transactional(readonly = false, propagation = propagation.requires_new)   public object update(object o) {       object = this.entitymanager.merge(o);       this.entitymanager.flush();       return a; } 

any appreciated.

some questions :

• how getuser() method work ?
• don't use detached objects ?
• is associated record loaded database ?

detached objects not linked original version, origin of word detached. helps hibernate doing comparison, forces full upgrade.

as saw on springsource forum, works when option select-before-update set true seems quite logical hibernate has changed. select-before-update option forces have read original.

if application reads user database , not working detached objects can't more ideas...