Second level cache performace.

ford · **Joined:** Thu Oct 21, 2004 11:58 am **Posts:** 3

Hibernate version: 2.1
Hi,
I am using second level cache with ehcache provider. It seems between 3 or 4 times slower than first level cache. Maybe i am doing something wrong. What can i do to optimize second level cache?
Thanks.

Mapping documents:
This is my class:

Code:

<class name="VerticeHB" table="VERTICE" mutable="false" >
  <cache usage="read-only"/>      
    <id name="id" column="id" type="long">
      <generator class="sequence">
        <param name="sequence">mls.vertice_seq</param>
      </generator> 
    </id>
    <set name="arista" lazy="true" inverse="true" >
      <cache usage="read-only"/>
      <key column="id_parent"/>
      <one-to-many class="AristaHB"/>
    </set>
</class>

And ehcache.xml:

Code:

<ehcache>
  <diskStore path="java.io.tmpdir"/>
  <defaultCache maxElementsInMemory="10000" eternal="false"  timeToIdleSeconds="120" timeToLiveSeconds="240" overflowToDisk="false"/>
      
  <cache name="VerticeHB" maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="3000" timeToLiveSeconds="6000" overflowToDisk="false"/>   
</ehcache>   

anthony · **Posted:** Fri Oct 22, 2004 6:48 am

show java code

ford · **Joined:** Thu Oct 21, 2004 11:58 am **Posts:** 3

I am developing a routing application. When i use 'Session' without close, it is faster that if open and close every time. Sometime it needs to check 200,000 vertex, and it must be very fast. Complete code is too large, but i show fundamental code.

Thanks again

The class'VerticeHB' is vertex object and AristaHB link object.

Code:

public static SessionFactory sessionFactory;
static{
   sessionFactory = new Configuration().configure().buildSessionFactory();
}

Session session = sessionFactory.openSession();
VerticeHB verticeHB;
// get initial vertex.
verticeHB = (VerticeHB) session.load(VerticeHB.class,new Long(id));
Vector vector = new Vector();
vector.add(verticeHB);
Iterator iterator;
AristaHB aristaHB;
while (vector.size()>0){
  //...
  // if (vertexFound) return;
  verticeHB = vector.remove(0);
  // get their links.
  Set set = verticeHB.getArista();
  iterator = set.iterator();
  while (iterator.hasNext()){
    aristaHB = (AristaHB) iterator.next();
    // we get next vertex of our route graph.
    vector.add((VerticeHB)aristaHB.getId2());
  }
  //...
}
ss.close();

anthony · **Posted:** Fri Oct 22, 2004 8:06 am

you have to cache collection too

ford · **Joined:** Thu Oct 21, 2004 11:58 am **Posts:** 3

Thanks for reply quickly!
In the first post, i do not write all the code to simplify. I cache VerticeHB, AristaHB and VerticeHB.arista (the collection). Perhaps cache`s collection is wrong.
Thanks!

Complete mapping code:

Vertice.hbm.xml

Code:

<hibernate-mapping>
  <class name="VerticeHB" table="MLS.VERTICE" mutable="false" >
    <cache usage="read-only"/>
    <id name="id" column="id" type="long">
      <generator class="sequence">
        <param name="sequence">mls.vertice_seq</param>
      </generator> 
    </id>
    <property name="x"/>
    <property name="y"/>      
    <set name="arista" lazy="true" inverse="true" >
      <cache usage="read-only"/>
      <key column="id_parent"/>
      <one-to-many class="AristaHB"/>
    </set>
  </class>
  <class name="AristaHB" table="MLS.V_ARISTA" mutable="false">
    <cache usage="read-only"/>
    <id name="idA" column="id_A">
      <generator class="sequence">
        <param name="sequence">mls.vertice_seq</param>
      </generator>
    </id>
    <many-to-one name="id1" column="id_parent" not-null="true" />
    <many-to-one name="id2" column="id_next" not-null="true" />
  </class>
</hibernate-mapping>

And ehcache.xml

Code:

<ehcache>
  <diskStore path="java.io.tmpdir"/>
  <defaultCache maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="120" timeToLiveSeconds="240" overflowToDisk="false"/>
  <cache name="AristaHB" maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="3000" timeToLiveSeconds="6000" overflowToDisk="false"/>
  <cache name="VerticeHB" maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="3000" timeToLiveSeconds="6000" overflowToDisk="false"/>
  <!-- The collection -->
  <cache name="VerticeHB.arista" maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="3000" timeToLiveSeconds="6000" overflowToDisk="false"/>
</ehcache>

anthony · **Posted:** Fri Oct 22, 2004 10:05 am

what do you see in generated sql, for the 1st query execution and the second