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

[cloutierm]

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

	<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" />

			<property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider" />
		</properties>
	</persistence-unit>

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