Hibernate HQL optimization
hello Hibernate gurus!
I would like to improve my app performance through HQL optimzation.
I have a small example to show my problem:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="hibernate.classes.Peoples" table="PEOPLES" catalog="Dev1">
<id name="PId" type="int">
<column name="P_ID" />
<generator class="identity"/>
</id>
<property name="pfirstname" type="string">
<column name="p_firstname" />
</property>
<property name="plastname" type="string">
<column name="p_lastname" />
</property>
<property name="phobby" type="string">
<column name="p_hobby" />
</property>
<many-to-one name="address" class="hibernate.classes.Address" fetch="join" insert="false" update="false">
<column name="p_adress" not-null="true"/>
</many-to-one>
</class>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="hibernate.classes.Address" table="ADDRESS" catalog="Dev1">
<id name="AId" type="int">
<column name="A_ID" />
<generator class="identity"/>
</id>
<property name="street" type="string">
<column name="a_street" />
</property>
<property name="house" type="string">
<column name="a_house" />
</property>
<property name="district" type="string">
<column name="a_district" />
</property>
</class>
I'd like to display rows from people and also show the appropriate person's address (foreign key bind)
When i use HQL join like this way:
session.createQuery("from Peoples inner join Address")
I suppose in this case .tolist() does not work properly becouse there are additional join properties.
When i use simple ("from Peopes") HQL query together with many-to-one default lazy="proxy" the result
will be terrible slow.
Hibernate try to gets seperatly every row from Address with foreign key selects. (May is it the N+1 Select problem?)
This is an impact when i have many rows in my table.
What is the best practice when i always want to display this cross joined datas?
(pfirstname, plastname, phobby, street, house)
Should i use iterator and manually place each property from the query result?
Thanks in advance!
Sorry for the dummy question! :S
