Question

我有我认为是一个非常标准的设置... spring，jpa（hibernate），我正在尝试添加ehcache。

我已全部配置并验证它正在工作...我正在记录hibernate sql语句和缓存语句，并且可以看到缓存被调用，并且一旦对象在缓存中，当我尝试再次加载，sql语句没有被写出（即，它没有到达数据库）。

然而，性能非常糟糕......如果我从缓存或数据库中获取对象，它的性能几乎相同。我怀疑问题可能与spring自动刷新hibernate会话有关，或者开销是由于事务（我试图关闭该方法），或者我使用c3p0的连接池运行不正常足够。无论如何，我有点亏......

我会发布我拥有的所有相关信息，希望这里的一些天才可以帮助我，否则我会陷入困境。

首先，我的春季配置：

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:hprof="http://www.nhprof.com/schema/hprof"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
http://www.nhprof.com/schema/hprof http://www.nhprof.com/schema/hprof/hprof.xsd">


<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

<bean id="systemPropertyManager" class="com.service.impl.SystemPropertyManagerImpl" />
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
     <property name="dataSource" ref="mysql" /> 
    <property name="jpaVendorAdapter">
        <bean
            class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
            <property name="database" value="MYSQL" />
            <property name="showSql" value="true" />
        </bean>
    </property>
    <property name="jpaProperties">
        <props>

           <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
           <!-- always puts logging out to the console...we want it in the log file -->
           <prop key="hibernate.connection.show_sql">false</prop>
           <prop key="hibernate.hbm2ddl.auto">update</prop>
       <prop key="hibernate.cache.provider_class">net.sf.ehcache.hibernate.SingletonEhCacheProvider</prop>
       <prop key="net.sf.ehcache.configurationResourceName">ehcache.xml</prop>
           <prop key="hibernate.cache.use_second_level_cache">true</prop>
           <prop key="hibernate.cache.use_structured_entries">true</prop>
           <prop key="hibernate.cache.use_query_cache">true</prop>
           <prop key="hibernate.generate_statistics">true</prop>
           <prop key="hibernate.default_batch_fetch_size">500</prop>
           <prop key="hibernate.max_fetch_depth">5</prop>
           <prop key="hibernate.jdbc.batch_size">1000</prop>
           <prop key="hibernate.use_outer_join">true</prop>
        </props>
    </property> 
 <!--   <hprof:profiler /> -->
</bean>


 <bean id="mysql" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
  <property name="driverClass" value="com.mysql.jdbc.Driver" />
    <property name="jdbcUrl" value="jdbc:mysql://localhost/daily?relaxAutoCommit=true&amp;useUnicode=true&amp;characterEncoding=UTF-8&amp;jdbcCompliantTruncation=false&amp;emulateLocators=true" />
    <property name="user" value="root" />
    <property name="password" value="" />
    <property name="initialPoolSize"><value>5</value></property>
    <property name="minPoolSize"><value>5</value></property>
    <property name="maxPoolSize"><value>50</value></property>
    <property name="idleConnectionTestPeriod"><value>200</value></property>
    <property name="acquireIncrement"><value>3</value></property>
    <property name="numHelperThreads"><value>3</value></property>
</bean>

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

<tx:annotation-driven transaction-manager="transactionManager" />

我的ehcache文件如下

<ehcache>
<diskStore path="c:/cache"/>

    <defaultCache eternal="false" 
            overflowToDisk="false"
            maxElementsInMemory="50000" 
            timeToIdleSeconds="30" 
            timeToLiveSeconds="6000"
            memoryStoreEvictionPolicy="LRU"
            />
    <cache name="com.model.SystemProperty"
            maxElementsInMemory="5000"
            eternal="true"
            overflowToDisk="false"
            memoryStoreEvictionPolicy="LFU" />

为了调用缓存而注释的我的缓存对象如下：

package com.model;

import javax.persistence.*;

import org.hibernate.annotations.Cache;
import org.hibernate.annotations.CacheConcurrencyStrategy;

@Entity
@Cache(usage = CacheConcurrencyStrategy.READ_ONLY, region="com.model.SystemProperty", include="non-lazy")
@EntityListeners(com.util.GenericEntityLogger.class)
public class SystemProperty extends BaseObject{

    private String name;
    private String value;

    // default constructor
    public SystemProperty(){

    }
    public SystemProperty(String name, String value){
        this.name = name;
        this.value = value;
    }

    @Id
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public String getValue() {
        return value;
    }
    public void setValue(String value) {
        this.value = value;
    }

    @Override
    public boolean equals(Object o) {
        // TODO Auto-generated method stub
        return false;
    }
    @Override
    public int hashCode() {
        // TODO Auto-generated method stub
        return 0;
    }
    @Override
    public String toString() {
        // TODO Auto-generated method stub
        return null;
    }


}

我的接口用于保存并使用spring @Transactional方法获取SystemProperty对象，我的实现如下：

package com.service.impl;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.transaction.annotation.Transactional;

import com.model.SystemProperty;
import com.service.SystemPropertyManager;


public class SystemPropertyManagerImpl extends BaseManagerImpl implements SystemPropertyManager {

    // logging
    protected final Log log = LogFactory.getLog(getClass());

    public SystemProperty find(String name){
        return (SystemProperty) super.entityManager.find(SystemProperty.class, name);
    }

    @Transactional
    public SystemProperty save(SystemProperty prop){
        return (SystemProperty) super.save(prop);
    }

}

请注意@Transactional仅适用于save方法。最后，我用3000个系统属性对象填充了mysql数据库，然后编写了一个测试文件，将它们加载两次。

第一次加载它们时，我可以看到生成的sql并且缓存没有被命中。第二次，缓存确实被命中，并且没有生成sql。

单元测试：

    @Test
public void testGetCachedUser1(){
    log.debug("starting testGetCachedUser");
    SystemPropertyManager mgr = ManagerFactory.getSystemPropertyManager();
    EntityManager em = mgr.getEntityManager();

    log.debug("start timing 1");
    for(int i = 0; i<3000; i ++){
        mgr.find("name_"+i);
    }
    log.debug("end timing 1");
    log.debug("start timing 2");
    for(int i = 0; i<3000; i ++){
        mgr.find("name_"+i);
    }
    log.debug("end timing 2");
}

日志文件包含大量信息。我将在“开始时间1”区域中发布日志文件中的部分。这对应于仅当它不在缓存中时加载的第一个对象发生的事情：

DEBUG 2010-10-22 11:57:49,533 [main][] org.springframework.transaction.annotation.AnnotationTransactionAttributeSource - Adding transactional method [find] with attribute [PROPAGATION_REQUIRED,ISOLATION_DEFAULT]
DEBUG 2010-10-22 11:57:49,533 [main][] org.hibernate.impl.SessionImpl - opened session at timestamp: 5274603804807168
DEBUG 2010-10-22 11:57:49,533 [main][] org.hibernate.transaction.JDBCTransaction - begin
DEBUG 2010-10-22 11:57:49,533 [main][] org.hibernate.jdbc.ConnectionManager - opening JDBC connection
DEBUG 2010-10-22 11:57:49,533 [main][] com.mchange.v2.resourcepool.BasicResourcePool - trace com.mchange.v2.resourcepool.BasicResourcePool@4e2f0a [managed: 5, unused: 4, excluded: 0] (e.g. com.mchange.v2.c3p0.impl.NewPooledConnection@1631573)
DEBUG 2010-10-22 11:57:49,533 [main][] org.hibernate.transaction.JDBCTransaction - current autocommit status: true
DEBUG 2010-10-22 11:57:49,533 [main][] org.hibernate.transaction.JDBCTransaction - disabling autocommit
DEBUG 2010-10-22 11:57:49,533 [main][] org.hibernate.jdbc.JDBCContext - after transaction begin
DEBUG 2010-10-22 11:57:49,549 [main][] org.springframework.transaction.support.TransactionSynchronizationManager - Bound value [org.springframework.jdbc.datasource.ConnectionHolder@5fbbf3] for key [com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 31ghzi8b1mphf1c19l14qo|149105b, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.p6spy.engine.spy.P6SpyDriver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 31ghzi8b1mphf1c19l14qo|149105b, idleConnectionTestPeriod -> 200, initialPoolSize -> 5, jdbcUrl -> jdbc:mysql://localhost/daily?relaxAutoCommit=true&useUnicode=true&characterEncoding=UTF-8&jdbcCompliantTruncation=false&emulateLocators=true, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 50, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 5, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]] to thread [main]
DEBUG 2010-10-22 11:57:49,549 [main][] org.springframework.transaction.support.TransactionSynchronizationManager - Bound value [org.springframework.orm.jpa.EntityManagerHolder@1bb03ee] for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean@11b99c4] to thread [main]
DEBUG 2010-10-22 11:57:49,549 [main][] org.springframework.transaction.support.TransactionSynchronizationManager - Initializing transaction synchronization
DEBUG 2010-10-22 11:57:49,549 [main][] org.springframework.transaction.interceptor.TransactionInterceptor - Getting transaction for [com.service.SystemPropertyManager.find]
DEBUG 2010-10-22 11:57:49,549 [main][] org.springframework.transaction.support.TransactionSynchronizationManager - Retrieved value [org.springframework.orm.jpa.EntityManagerHolder@1bb03ee] for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean@11b99c4] bound to thread [main]
DEBUG 2010-10-22 11:57:49,549 [main][] org.hibernate.event.def.DefaultLoadEventListener - loading entity: [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,549 [main][] org.hibernate.event.def.DefaultLoadEventListener - attempting to resolve: [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,549 [main][] org.hibernate.event.def.DefaultLoadEventListener - object not resolved in any cache: [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,549 [main][] org.hibernate.persister.entity.AbstractEntityPersister - Fetching entity: [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,549 [main][] org.hibernate.loader.Loader - loading entity: [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,549 [main][] org.hibernate.jdbc.AbstractBatcher - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
DEBUG 2010-10-22 11:57:49,549 [main][] org.hibernate.SQL - select systemprop0_.name as name11_0_, systemprop0_.value as value11_0_ from SystemProperty systemprop0_ where systemprop0_.name=?
DEBUG 2010-10-22 11:57:49,549 [main][] org.hibernate.jdbc.AbstractBatcher - preparing statement
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.type.StringType - binding 'name_0' to parameter: 1
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.jdbc.AbstractBatcher - about to open ResultSet (open ResultSets: 0, globally: 0)
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.loader.Loader - processing result set
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.loader.Loader - result set row: 0
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.loader.Loader - result row: EntityKey[com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.loader.Loader - Initializing object from ResultSet: [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.persister.entity.AbstractEntityPersister - Hydrating entity: [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.type.StringType - returning 'value_0' as column: value11_0_
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.loader.Loader - done processing result set (1 rows)
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.jdbc.AbstractBatcher - about to close ResultSet (open ResultSets: 1, globally: 1)
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.jdbc.AbstractBatcher - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.jdbc.AbstractBatcher - closing statement
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.loader.Loader - total objects hydrated: 1
DEBUG 2010-10-22 11:57:49,580 [main][] org.hibernate.engine.TwoPhaseLoad - resolving associations for [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.engine.TwoPhaseLoad - adding entity to second-level cache: [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.cache.ReadOnlyCache - Caching: com.model.SystemProperty#name_0
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.engine.TwoPhaseLoad - done materializing entity [com.model.SystemProperty#name_0]
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.engine.StatefulPersistenceContext - initializing non-lazy collections
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.loader.Loader - done entity load
DEBUG 2010-10-22 11:57:49,596 [main][] org.springframework.transaction.interceptor.TransactionInterceptor - Completing transaction for [com.service.SystemPropertyManager.find]
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.transaction.JDBCTransaction - commit
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.impl.SessionImpl - automatically flushing session
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - flushing session
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - processing flush-time cascades
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.engine.Cascade - processing cascade ACTION_PERSIST_ON_FLUSH for: com.model.SystemProperty
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.engine.Cascade - done processing cascade ACTION_PERSIST_ON_FLUSH for: com.model.SystemProperty
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - dirty checking collections
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - Flushing entities and processing referenced collections
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - Processing unreferenced collections
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - Scheduling collection removes/(re)creates/updates
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - Flushed: 0 insertions, 0 updates, 0 deletions to 1 objects
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.pretty.Printer - listing entities:
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.pretty.Printer - com.model.SystemProperty{name=name_0, value=value_0}
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - executing flush
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.jdbc.ConnectionManager - registering flush begin
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.jdbc.ConnectionManager - registering flush end
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.event.def.AbstractFlushingEventListener - post flush
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.jdbc.JDBCContext - before transaction completion
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.impl.SessionImpl - before transaction completion
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.transaction.JDBCTransaction - re-enabling autocommit
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.transaction.JDBCTransaction - committed JDBC Connection
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.jdbc.JDBCContext - after transaction completion
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.jdbc.ConnectionManager - releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
DEBUG 2010-10-22 11:57:49,596 [main][] com.mchange.v2.resourcepool.BasicResourcePool - trace com.mchange.v2.resourcepool.BasicResourcePool@4e2f0a [managed: 5, unused: 4, excluded: 0] (e.g. com.mchange.v2.c3p0.impl.NewPooledConnection@1631573)
DEBUG 2010-10-22 11:57:49,596 [main][] org.hibernate.impl.SessionImpl - after transaction completion
DEBUG 2010-10-22 11:57:49,596 [main][] org.springframework.transaction.support.TransactionSynchronizationManager - Clearing transaction synchronization
DEBUG 2010-10-22 11:57:49,596 [main][] org.springframework.transaction.support.TransactionSynchronizationManager - Removed value [org.springframework.orm.jpa.EntityManagerHolder@1bb03ee] for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean@11b99c4] from thread [main]
DEBUG 2010-10-22 11:57:49,612 [main][] org.springframework.transaction.support.TransactionSynchronizationManager - Removed value [org.springframework.jdbc.datasource.ConnectionHolder@5fbbf3] for key [com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 31ghzi8b1mphf1c19l14qo|149105b, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.p6spy.engine.spy.P6SpyDriver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 31ghzi8b1mphf1c19l14qo|149105b, idleConnectionTestPeriod -> 200, initialPoolSize -> 5, jdbcUrl -> jdbc:mysql://localhost/daily?relaxAutoCommit=true&useUnicode=true&characterEncoding=UTF-8&jdbcCompliantTruncation=false&emulateLocators=true, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 50, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 5, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]] from thread [main]
DEBUG 2010-10-22 11:57:49,612 [main][] org.hibernate.impl.SessionImpl - closing session
DEBUG 2010-10-22 11:57:49,612 [main][] org.hibernate.jdbc.ConnectionManager - connection already null in cleanup : no action

你可以看到它被加载到缓存中，hibernate会话被打开，关闭和刷新。

我会在下面的评论中发布我的第二个日志文件，因为我已经达到了这个问题的最大长度。重点是，一切看起来都不错，唯一真正的问题是它太慢了。

当我第一次加载3000个对象（即击中数据库）时，它与第二次（即击中缓存）几乎完全相同。就像我说的那样，开销和关闭连接，刷新会话，处理交易是否成本？我不确定。但无论如何它都是非常残酷的。帮我stackoverflow ...你是我唯一的希望:)。

Answer 1

我建议尝试用普通的应用程序缓存替换第二级缓存使用。当我在过去测试Hibernate的二级缓存性能时，我注意到它不是很有效。这是由于缓存数据的结构方式 - 类似于结果集 - 表格数据是存储的，而不是对象。这意味着许多缓存请求，结果证明是昂贵的。

为了将缓存代码与持久性逻辑分开，我使用AOP。既然你使用Spring就应该很容易。

Answer 2

重点是，一切看起来都不错，唯一真正的问题是它太慢了。

该死的是一个主观的测量单位：）

当我第一次加载3000个对象（即击中数据库）时，它与第二次完全相同（即，点击缓存）。

使用System.nanoTime()

显示指标，没有所有日志记录开销（也没有P6Spy）

long startTime = System.nanoTime();
// ... the code being measured ...
long estimatedTime = System.nanoTime() - startTime;

也许还尝试使用单个EntityManager在单个事务中执行测试，只是为了查看在这些条件下的行为。

就像我说的那样，开销和关闭连接，刷新会话，处理交易是否成本？我不确定。但无论如何，它都是非常残酷的。

不能说，您应该分析您的代码以查看花费的时间（并监控GC活动）。

但理论上：

connection中的Session是懒惰的（仅在需要时才会被获取）
从C3P0获取connection应该非常快（可以忽略不计）
由于您的实体以只读方式缓存，flush应该非常快

换句话说，我不希望上述操作很昂贵（所以我会专注于周围的部分）。但正如我所说，配置文件（并监控GC活动）。

Answer 3

你确定你没有在缓存通话中击中数据库吗？启用hibernate sql debug logger以查看它是否正在做正确的事情。我之前从未使用过实体经理。我总是使用hibernate会话。如果启用查询缓存，则仍需要在hibernate查询中执行setCache（true）。否则，它仍然会击中db。实体中的@Cache注释仅在ehcache中通过id缓存它。当您将查询设置为可缓存时，缓存键是您的查询，结果是实体ID，然后它将尝试通过id解析ehcache中的实体。

Answer 4

您的测试在没有事务的情况下直接使用EntityManager。 EntityManager的范围限定为单个工作单元，通常是单个事务。你可能正在强迫新的交易包括。每次查找调用在数据库连接池中查找。

以下是我的建议：

对非保存方法使用只读事务而不是无TX划分
将您的DataSource bean包装在LazyConnectionDataSourceProxy中，以避免在您实际上不需要与数据库通信时获取连接（即在高速缓存命中的情况下）
更新您的测试以与您的服务bean通信，而不是直接使用EntityManager。

Spring，JPA（Hibernate）＆amp; Ehcache表现不佳

4 个答案: