Hibernate 캐시 상세 정보
데이터베이스 캐시는 응용 프로그램과 물리적 데이터 원본 사이의 데이터를 가리킨다.물리적 데이터 원본의 데이터를 캐시로 복사하는 것이다.캐시가 있으면 응용 프로그램이 물리적 데이터 원본에 대한 접근 빈도를 낮추어 효율을 높일 수 있다.캐시된 미디어는 일반적으로 메모리일 수도 있고 하드디스크일 수도 있다.
Hibernate의 캐시는 세 가지 유형이 있는데 그것이 바로 1급 캐시, 2급 캐시, 조회 캐시입니다.
2.1 레벨 캐시
1레벨 캐시는 Session 캐시로 Session에서 자동으로 관리되며 프로그램이 관여할 필요가 없습니다.1 레벨 캐시는 객체의 ID에 따라 로드되고 캐시됩니다.다음 코드:
@Override
public void testCache() {
// TODO Auto-generated method stub
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Course c = (Course) session.get(Course.class, 1);
System.out.println("Name:" + c.getName());
c = (Course) session.get(Course.class, 1);
System.out.println("Name:" + c.getName());
tx.commit();
session.close();
}
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Name:
Name: 다시 한 번 예를 들자.
@Override
public void testCache() {
// TODO Auto-generated method stub
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Course c = (Course) session.get(Course.class, 1);
System.out.println("Name:" + c.getName());
tx.commit();
session.close();
session = sessionFactory.openSession();
tx = session.beginTransaction();
c = (Course) session.get(Course.class, 1);
System.out.println("Name:" + c.getName());
tx.commit();
session.close();
}
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Name:
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Name: 2 레벨 캐시는 SessionFactory 캐시입니다. 1 레벨 캐시와 유사하고 대상의 ID에 따라 캐시를 불러오고 캐시합니다. 차이점은 1 레벨 캐시는 Session 내에서만 유효하고 2 레벨 캐시는 SessionFactory 내에서만 유효하다는 것입니다.ID의 객체에 액세스할 때 먼저 1레벨 캐시에서 찾고 찾을 수 없으면 2레벨 캐시에서 찾습니다.2단계 캐시는 EHCache, OSCache, SwarmCache와 JBossCache 등을 포함한다.여기에는 EHCache를 예로 들 수 있습니다.
2단계 캐시는 프로그램이 관리해야 한다.먼저 Maven 다운로드와 관련된 Jar를 구성하여 pom 파일에 추가합니다.
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-ehcache</artifactId>
<version>4.1.0.Final</version>
</dependency>
<dependency>
<groupId>net.sf.ehcache</groupId>
<artifactId>ehcache</artifactId>
<version>2.8.3</version>
</dependency>
<ehcache>
<diskStore path="E:\Eclipse\MyWorkspace\Cache"/>
<defaultCache
maxElementsInMemory="10000"
eternal="true"
timeToIdleSeconds="120"
timeToLiveSeconds="120"
overflowToDisk="true"
/>
<cache name="com.hzhi.course.entity.Course"
maxElementsInMemory="10000"
eternal="true"
timeToIdleSeconds="300"
timeToLiveSeconds="600"
overflowToDisk="true"
/>
</ehcache>캐시가 필요한 클래스의 hbm 파일 수정:
<class name="com.hzhi.course.entity.Course" table="clas">
<cache usage="read-only"/>
......
</class>응용 프로그램 컨텍스트를 수정합니다.xml의 SessionFactory 설정으로 2단계 캐시의 속성을 추가합니다.
<!-- SessionFactory -->
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" >
<ref local="dataSource"/>
</property>
<!-- Hibernate -->
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.format_sql">true</prop>
<prop key="hibernate.connection.isolation">8</prop>
<!-- -->
<prop key="hibernate.cache.use_second_level_cache">false</prop>
<prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">WEB-INF/ehcache.xml</prop>
</props>
</property>
......
</bean>
@Override
public void testCache() {
// TODO Auto-generated method stub
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Course c = (Course) session.get(Course.class, 1);
System.out.println("Name:" + c.getName());
tx.commit();
session.close();
session = sessionFactory.openSession();
tx = session.beginTransaction();
c = (Course) session.get(Course.class, 1);
System.out.println("Name:" + c.getName());
tx.commit();
session.close();
}
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Name:
Name: 다음 예:
@Override
public void testCache() {
// TODO Auto-generated method stub
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Query query = session.createQuery("from Course");
Iterator iter = query.iterate();
while(iter.hasNext()){
System.out.println(((Course)iter.next()).getName());
}
tx.commit();
session.close();
session = sessionFactory.openSession();
tx = session.beginTransaction();
query = session.createQuery("from Course");
iter = query.iterate();
while(iter.hasNext()){
System.out.println(((Course)iter.next()).getName());
}
tx.commit();
session.close();
}
Hibernate:
select
course0_.ID as col_0_0_
from
clas course0_
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
C
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
A
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Java
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Linux
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as col_0_0_
from
clas course0_
C
A
Java
Linux
1레벨 캐시든 2레벨 캐시든 모두 대상만 캐시할 수 있고 속성의 값을 캐시할 수 없습니다.다음 예:
@Override
public void testCache() {
// TODO Auto-generated method stub
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Query query = session.createQuery("select c.name from Course c");
List<String> names = query.list();
for(Iterator iter = names.iterator(); iter.hasNext();){
String name = (String) iter.next();
System.out.println(name);
}
System.out.println("----------");
query = session.createQuery("select c.name from Course c");
names = query.list();
for(Iterator iter = names.iterator(); iter.hasNext();){
String name = (String) iter.next();
System.out.println(name);
}
System.out.println("----------");
tx.commit();
session.close();
}
Hibernate:
select
course0_.NAME as col_0_0_
from
clas course0_
C
A
Java
Linux
----------
Hibernate:
select
course0_.NAME as col_0_0_
from
clas course0_
C
A
Java
Linux
----------3. 쿼리 캐시
2단계 캐시를 설정한 토대에서 검색 캐시를 설정할 수 있고 SessionFactory 설정에 한 줄을 추가할 수 있습니다.
<prop key="hibernate.cache.use_query_cache">true</prop>쿼리 캐시가 열립니다.쿼리 캐시도 SessionFactory 레벨의 캐시로 전체 SessionFactory에서 유효합니다.2단계 캐시를 닫고 다음 예를 실행하여Query 뒤에 setCacheable(true)를 추가하여 쿼리 캐시를 엽니다.
@Override
public void testCache() {
// TODO Auto-generated method stub
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Query query = session.createQuery("select c.name from Course c");
query.setCacheable(true);
List<String> names = query.list();
for(Iterator iter = names.iterator(); iter.hasNext();){
String name = (String) iter.next();
System.out.println(name);
}
System.out.println("----------");
query = session.createQuery("select c.name from Course c");
query.setCacheable(true);
names = query.list();
for(Iterator iter = names.iterator(); iter.hasNext();){
String name = (String) iter.next();
System.out.println(name);
}
System.out.println("----------");
tx.commit();
session.close();
}
Hibernate:
select
course0_.NAME as col_0_0_
from
clas course0_
C
A
Java
Linux
----------
C
A
Java
Linux
----------
System.out.println("----------");
query = session.createQuery("select c.name from Course c where c.id > 5");
query.setCacheable(true);
names = query.list();
for(Iterator iter = names.iterator(); iter.hasNext();){
String name = (String) iter.next();
System.out.println(name);
}
System.out.println("----------");
Hibernate:
select
course0_.NAME as col_0_0_
from
clas course0_
C
A
Java
Linux
----------
Hibernate:
select
course0_.NAME as col_0_0_
from
clas course0_
where
course0_.ID>5
A
Java
Linux
----------쿼리 캐시는 속성을 캐시할 수도 있고 객체를 캐시할 수도 있지만 객체를 캐시할 때 객체의 ID만 캐시되고 전체 객체는 캐시되지 않습니다.다음 예:
@Override
public void testCache() {
// TODO Auto-generated method stub
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Query query = session.createQuery("from Course");
query.setCacheable(true);
List<Course> list = query.list();
for (int i=0; i<list.size(); i++){
System.out.println(list.get(i).getName());
}
System.out.println("----------");
tx.commit();
session.close();
session = sessionFactory.openSession();
tx = session.beginTransaction();
query = session.createQuery("from Course");
query.setCacheable(true);
list = query.list();
for (int i=0; i<list.size(); i++){
System.out.println(list.get(i).getName());
}
System.out.println("----------");
tx.commit();
session.close();
}
Hibernate:
select
course0_.ID as ID0_,
course0_.NAME as NAME0_,
course0_.COMMENT as COMMENT0_
from
clas course0_
C
A
Java
Linux
----------
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
Hibernate:
select
course0_.ID as ID0_0_,
course0_.NAME as NAME0_0_,
course0_.COMMENT as COMMENT0_0_
from
clas course0_
where
course0_.ID=?
C
A
Java
Linux
----------쿼리 캐시와 L2 캐시를 동시에 열면 두 번째 세션에서는 ID에 따라 SQL 문구를 생성할 필요가 없습니다.
Hibernate:
select
course0_.ID as ID0_,
course0_.NAME as NAME0_,
course0_.COMMENT as COMMENT0_
from
clas course0_
C
A
Java
Linux
----------
C
A
Java
Linux
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