Hibernate Many-to-one lazy loading is not working

spirit3189 picture spirit3189 · Apr 5, 2012 · Viewed 13.6k times · Source

I have a class and 2 many-to-one mappings in it , How can I lazy load them

My properties

**teneo.mapping.also_map_as_class=true
teneo.mapping.set_proxy=true
teneo.mapping.mapping_file_name=/lazy.hbm.xml**

Mapping file ( lazy.hbm.xml)

<class name="EnvironmentImpl" entity-name="**Environment**" abstract="false" lazy="true" discriminator-value="Environment" table="`ENVIRONMENT`" proxy="Environment">
    <meta attribute="eclassName">Environment</meta>

    <property name="name" lazy="false" insert="true" update="true" not-null="true" unique="false" type="java.lang.String">
        <column not-null="true" unique="false" name="`NAME`"/>
    </property>

    <property name="description" lazy="false" insert="true" update="true" not-null="false" unique="false" type="java.lang.String">
        <column not-null="false" unique="false" name="`DESCRIPTION`" length="512"/>
    </property>

    <property name="contact" lazy="false" insert="true" update="true" not-null="false" unique="false" type="java.lang.String">
        <column not-null="false" unique="false" name="`CONTACT`"/>
    </property>

    <many-to-one  name="rootAppFolder" entity-name="ApplicationFolder" lazy="proxy" cascade="all" foreign-key="ENVIRONMENT_ROOTAPPFOLDER" insert="true" update="true" not-null="false" unique="true">
        <column not-null="false" unique="false" name="`APPLICATINFLDER_RTAPPFOLDER_ID`"/>
    </many-to-one>

    <many-to-one name="serviceVirtualization" entity-name="ServiceVirtualization" lazy="proxy" cascade="all" foreign-key="ENVIRNMENT_SERVICEVIRTALIZATIN" insert="true" update="true" not-null="false">
        <column not-null="false" unique="false" name="`SRVCVRTLZTN_SRVICVIRTLIZTIN_ID`"/>
    </many-to-one>
</class>

As you can see class Environment has 2 many-to-one's with names ApplicationFolder and serviceVirtualization.

for a HQL query like -  from Environment where name = :name


    Which internally triggers 3 queries  
    Query1 : Environment ( this is right)

    Query2 : ApplicationFolder ( wrong.lazy loading should not.)

    Query 3 : serviceVirtualization ( wrong.lazy loading should not.)



            DEBUG - select environmen0_."NAME" as NAME4_31_, environmen0_."DESCRIPTION" as DESCRIPT5_31_, environmen0_."CONTACT" as CONTACT6_31_, environmen0_."APPLICATINFLDER_RTAPPFOLDER_ID" as APPLICAT7_31_, environmen0_."SRVCVRTLZTN_SRVICVIRTLIZTIN_ID" as SRVCVRTL8_31_ from "ENVIRONMENT" environmen0_ where environmen0_."NAME"=?

            DEBUG - select applicatio0_.e_id as e1_43_0_, applicatio0_.version_ as version3_43_0_, applicatio0_."NAME" as NAME4_43_0_, applicatio0_."ENVIRONMENT_ENV_E_ID" as ENVIRONM5_43_0_ as APPLICAT8_43_0_ from "APPLICATIONFOLDER" applicatio0_ where applicatio0_.e_id=?

            DEBUG - select servicevir0_.e_id as e1_35_0_, servicevir0_.version_ as version3_35_0_, servicevir0_.econtainer_class as econtainer4_35_0_, servicevir0_.e_container as e5_35_0_, servicevir0_.e_container_featureid as e6_35_0_ from "SERVICEVIRTUALIZATION" servicevir0_ where servicevir0_.e_id=?

What approaches I tried so far 1) set lazy="no-proxy" , dont see any change in number of queries.

2) setting not-found="exception".

3)outer-join = "auto"

Can any one suggest me a solution to reduce those 2 extra queries getting fired because of the eager many-to-one relations ?

Please take a note of the foreign key relationships on many-to-one.

Answer

Firo picture Firo · Apr 7, 2012

lazy is true by default. try getting rid of lazy="proxy".

reasons for lazy not working:

  • when the referenced type can not be proxied because there is no default constructor or final methods
  • the referenced type is mapped with <class lazy="false"