"Cached Item Was Locked" causing Select Statement: EHCache +
cloutierm Mar 15, 2009 4:28 PM
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