0 Replies Latest reply on Mar 15, 2009 4:28 PM by Mark Cloutier

    "Cached Item Was Locked" causing Select Statement: EHCache +

    Mark Cloutier Newbie


      I am having trouble with getting some caching to work with hibernate exactly the way I would like. I created some example code to replicate this problem I am having.

      I have one object that contains instances of itself. For instance, a Part that is made up of more Parts.

      I really need to minimize the select statements that Hibernate is using when an updated object comes in. After going through the logs, I see this log output that is causing a SELECT statement:

      Cached item was locked: com.cache.dataobject.Part.parts#1

      What can I change in my annotation mappings, xml files, or logic to keep the cached item from being locked? I would really like to get rid of that select statement.

      I included the Entity, DataObject, code I am testing with, and log output.


      Hibernate version: 3.4

      EHCache Version: 1.2.3 (Included with Hibernate Download)

      Part DataObject

      package com.cache.dataobject;
      
      import java.io.Serializable;
      import java.lang.String;
      import java.util.List;
      
      import javax.persistence.*;
      
      import org.hibernate.annotations.Cache;
      import org.hibernate.annotations.CacheConcurrencyStrategy;
      
      import static javax.persistence.CascadeType.ALL;
      
      /**
       * Entity implementation class for Entity: Part
       *
       */
      @Entity
      @Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
      public class Part implements Serializable {
      
       private int id;
       private String name;
       private static final long serialVersionUID = 1L;
       private Part mainPart;
       private List<Part> parts;
      
       public Part() {
       super();
       }
      
       @Id
       public int getId() {
       return this.id;
       }
      
       public void setId(int id) {
       this.id = id;
       }
      
       @Column(name = "PART_NAME")
       public String getName() {
       return this.name;
       }
      
       public void setName(String name) {
       this.name = name;
       }
      
       @ManyToOne(cascade = ALL)
       public Part getMainPart() {
       return mainPart;
       }
      
       public void setMainPart(Part mainPart) {
       this.mainPart = mainPart;
       }
      
       @OneToMany(cascade = ALL)
       @JoinColumn(name = "mainPart_id", referencedColumnName = "id")
       @Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
       public List<Part> getParts() {
       return parts;
       }
      
       public void setParts(List<Part> parts) {
       this.parts = parts;
       }
      
      }


      CacheDao
      package com.cache.dao;
      
      import java.util.List;
      
      import javax.ejb.Stateless;
      import javax.persistence.EntityManager;
      import javax.persistence.PersistenceContext;
      import javax.persistence.Query;
      
      import com.cache.dataobject.Part;
      
      /**
       * Session Bean implementation class CacheDao
       */
      @Stateless(mappedName = "ejb/CacheDao")
      public class CacheDao implements CacheDaoRemote {
      
       @PersistenceContext(unitName="CacheProjectUnit")
       EntityManager em;
      
       /**
       * Default constructor.
       */
       public CacheDao() {
       // TODO Auto-generated constructor stub
       }
      
       public Part addPart(Part part){
       System.out.println("CALLED PERSIST");
       em.persist(part);
       return part;
       }
      
       public Part updatePart(Part part){
       System.out.println("CALLED MERGE");
       em.merge(part);
       return part;
       }
      
      }


      Test Client Code
      package com.cache.dao;
      
      import java.util.ArrayList;
      import java.util.List;
      
      import javax.naming.InitialContext;
      import javax.naming.NamingException;
      
      import com.cache.dao.CacheDaoRemote;
      import com.cache.dataobject.Part;
      
      
      public class test {
      
       /**
       * @param args
       */
       public static void main(String[] args) {
       InitialContext ctx;
       try {
       ctx = new InitialContext();
       CacheDaoRemote dao = (CacheDaoRemote) ctx.lookup("ejb/CacheDao");
       Part computer = new Part();
       computer.setId(1);
       computer.setName("Computer");
      
       List<Part> parts = new ArrayList<Part>();
      
       Part cpu = new Part();
       cpu.setId(2);
       cpu.setName("CPU");
      
       Part monitor = new Part();
       monitor.setId(3);
       monitor.setName("Monitor");
      
       parts.add(cpu);
       parts.add(monitor);
      
       computer.setParts(parts);
      
       dao.addPart(computer);
      
       computer.setName("DellComputer");
      
       dao.updatePart(computer);
      
      
       } catch (NamingException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
       }
      
       }
      
      }
      


      Persistence.xml

      <?xml version="1.0" encoding="UTF-8"?>
      <persistence version="1.0"
       xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
       <persistence-unit name="CacheProjectUnit">
       <provider>org.hibernate.ejb.HibernatePersistence</provider>
       <!-- JNDI name of the database resource to use -->
       <jta-data-source>jdbc/H2Pool</jta-data-source>
       <properties>
       <!-- The database dialect to use -->
       <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
       <!-- drop and create tables at deployment -->
       <property name="hibernate.hbm2ddl.auto" value="create-drop" />
       <property name="hibernate.max_fetch_depth" value="3" />
       <!-- Hibernate Query Language (HQL) parser. -->
       <property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider" />
       </properties>
       </persistence-unit>
      </persistence>


      EhCache.xml

      <ehcache>
       <diskStore path="java.io.tmpdir"/>
      
       <defaultCache
       maxElementsInMemory="10000"
       eternal="false"
       timeToIdleSeconds="120"
       timeToLiveSeconds="120"
       overflowToDisk="true"
       diskPersistent="false"
       diskExpiryThreadIntervalSeconds="120"
       memoryStoreEvictionPolicy="LRU"
       />
      
      
       <cache name = "com.cache.dataobject.Part"
       maxElementsInMemory="100000"
       eternal="true"
       diskPersistent="false"
       timeToIdleSeconds="0"
       timeToLiveSeconds="0"
       />
      
      
       <cache name = "com.cache.dataobject.Part.parts"
       maxElementsInMemory="100000"
       eternal="true"
       diskPersistent="false"
       timeToIdleSeconds="0"
       timeToLiveSeconds="0"
       />
      
      
      </ehcache>



      Output Log:

      INFO: CALLED PERSIST
      FINEST: Cache lookup: com.cache.dataobject.Part#1
      FINE: key: com.cache.dataobject.Part#1
      FINE: Element for com.cache.dataobject.Part#1 is null
      FINEST: Cache miss: com.cache.dataobject.Part#1
      FINEST: Cache lookup: com.cache.dataobject.Part#2
      FINE: key: com.cache.dataobject.Part#2
      FINE: Element for com.cache.dataobject.Part#2 is null
      FINEST: Cache miss: com.cache.dataobject.Part#2
      FINEST: Cache lookup: com.cache.dataobject.Part#3
      FINE: key: com.cache.dataobject.Part#3
      FINE: Element for com.cache.dataobject.Part#3 is null
      FINEST: Cache miss: com.cache.dataobject.Part#3
      FINEST: Invalidating: com.cache.dataobject.Part.parts#1
      FINE: key: com.cache.dataobject.Part.parts#1
      FINE: Element for com.cache.dataobject.Part.parts#1 is null
      FINE: insert into Part (mainPart_id, PART_NAME, id) values (?, ?, ?)
      FINE: insert into Part (mainPart_id, PART_NAME, id) values (?, ?, ?)
      FINE: insert into Part (mainPart_id, PART_NAME, id) values (?, ?, ?)
      FINE: update Part set mainPart_id=? where id=?
      FINE: update Part set mainPart_id=? where id=?
      FINEST: Inserting: com.cache.dataobject.Part#1
      FINE: key: com.cache.dataobject.Part#1
      FINE: Element for com.cache.dataobject.Part#1 is null
      FINEST: Inserted: com.cache.dataobject.Part#1
      FINEST: Inserting: com.cache.dataobject.Part#2
      FINE: key: com.cache.dataobject.Part#2
      FINE: Element for com.cache.dataobject.Part#2 is null
      FINEST: Inserted: com.cache.dataobject.Part#2
      FINEST: Inserting: com.cache.dataobject.Part#3
      FINE: key: com.cache.dataobject.Part#3
      FINE: Element for com.cache.dataobject.Part#3 is null
      FINEST: Inserted: com.cache.dataobject.Part#3
      FINEST: Releasing: com.cache.dataobject.Part.parts#1
      FINE: key: com.cache.dataobject.Part.parts#1

      INFO: CALLED MERGE
      FINEST: Cache lookup: com.cache.dataobject.Part#1
      FINE: key: com.cache.dataobject.Part#1
      FINEST: Cache hit: com.cache.dataobject.Part#1
      FINEST: Cache lookup: com.cache.dataobject.Part#1
      FINE: key: com.cache.dataobject.Part#1
      FINEST: Cache hit: com.cache.dataobject.Part#1
      FINEST: Cache lookup: com.cache.dataobject.Part#2
      FINE: key: com.cache.dataobject.Part#2
      FINEST: Cache hit: com.cache.dataobject.Part#2
      FINEST: Cache lookup: com.cache.dataobject.Part#2
      FINE: key: com.cache.dataobject.Part#2
      FINEST: Cache hit: com.cache.dataobject.Part#2
      FINEST: Cache lookup: com.cache.dataobject.Part#3
      FINE: key: com.cache.dataobject.Part#3
      FINEST: Cache hit: com.cache.dataobject.Part#3
      FINEST: Cache lookup: com.cache.dataobject.Part#3
      FINE: key: com.cache.dataobject.Part#3
      FINEST: Cache hit: com.cache.dataobject.Part#3
      FINEST: Cache lookup: com.cache.dataobject.Part.parts#1
      FINE: key: com.cache.dataobject.Part.parts#1
      FINEST: Cached item was locked: com.cache.dataobject.Part.parts#1
      FINE: select parts0_.mainPart_id as mainPart3_1_, parts0_.id as id1_, parts0_.id as id18_0_, parts0_.mainPart_id as mainPart3_18_0_, parts0_.PART_NAME as PART2_18_0_ from Part parts0_ where parts0_.mainPart_id=?
      FINEST: Caching: com.cache.dataobject.Part.parts#1
      FINE: key: com.cache.dataobject.Part.parts#1
      FINEST: Cached: com.cache.dataobject.Part.parts#1
      FINEST: Invalidating: com.cache.dataobject.Part.parts#2
      FINE: key: com.cache.dataobject.Part.parts#2
      FINE: Element for com.cache.dataobject.Part.parts#2 is null
      FINEST: Invalidating: com.cache.dataobject.Part.parts#3
      FINE: key: com.cache.dataobject.Part.parts#3
      FINE: Element for com.cache.dataobject.Part.parts#3 is null
      FINEST: Invalidating: com.cache.dataobject.Part.parts#1
      FINE: key: com.cache.dataobject.Part.parts#1
      FINEST: Invalidating: com.cache.dataobject.Part#1
      FINE: key: com.cache.dataobject.Part#1
      FINE: update Part set mainPart_id=?, PART_NAME=? where id=?
      FINE: update Part set mainPart_id=null where mainPart_id=?
      FINE: update Part set mainPart_id=null where mainPart_id=?
      FINEST: Updating: com.cache.dataobject.Part#1
      FINE: key: com.cache.dataobject.Part#1
      FINEST: Updated: com.cache.dataobject.Part#1
      FINEST: Releasing: com.cache.dataobject.Part.parts#2
      FINE: key: com.cache.dataobject.Part.parts#2
      FINEST: Releasing: com.cache.dataobject.Part.parts#3
      FINE: key: com.cache.dataobject.Part.parts#3
      FINEST: Releasing: com.cache.dataobject.Part.parts#1
      FINE: key: com.cache.dataobject.Part.parts#1