我目前在 Hibernate 中遇到性能问题

对于执行 SQL 语句(例如 select * from table)，仅需要大约 90ms 来获取 10 条 12 列的记录

但是，为了使 hibernate 运行在 DAO 类中的 java 代码之后

List<T> afterGetAll = getSessionFactory().getCurrentSession().createCriteria(type).list();

执行上述语句 ONLY 大约需要 260~300 毫秒才能完成，更不用说调用该 DAO 的服务类中的额外执行时间了。总共会花费大约 600~1000 毫秒。我怀疑大部分时间都花在了事务管理上。

我不确定我的代码/配置哪里出错了，我也尝试了以下方法但没有太大帮助......

1. 在数据源设置中添加连接池
2. 在 DAO 类中使用 hibernate native SQL 方法代替 createCriteria
3. 启用延迟加载
4. 增加 tomcat 服务器的堆大小
5. 使用二级缓存提供者
6. @Transactional(readOnly = true) 用于只读查询

一些加速操作的解决方法:

1. 通过配置EhCacheRegionFactory开启hibernate缓存，同时开启二级缓存。然后在服务器启动时，我的 Web 应用程序通过手动触发服务调用来初始化缓存。这可以成功地将 Hibernate 获取 sql 查询后的数据绑定(bind)过程从 300~400ms 减少到 1~3ms。然而，瓶颈在提交交易的时候......(见下面的Update#2)

这是我的配置和代码

hibernate 配置

<bean id="jdbcTemplate" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <property name="driverClass" value="com.mysql.jdbc.Driver" />
    <property name="jdbcUrl" value="jdbc:mysql://test />
    <property name="user" value="test" />
    <property name="password" value="test" />
    <property name="maxPoolSize" value="20" />
    <property name="minPoolSize" value="5" />
    <property name="maxStatements" value="5" />
</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="jdbcTemplate"></property>
    <property name="mappingResources">
        <list>
            <value>orm/UserModel.hbm.xml</value>
            <value>orm/UserToken.hbm.xml</value>
            <value>orm/RoleModel.hbm.xml</value>
        </list>
    </property>
    <property name="hibernateProperties">
      <props>
        <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
        <prop key="hibernate.show_sql">true</prop>
        <prop key="hibernate.format_sql">true</prop>
        <prop key="hibernate.use_sql_comments">true</prop>
        <prop key="hibernate.enable_lazy_load_no_trans">true</prop>
        <prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</prop>  
        <prop key="hibernate.cache.use_second_level_cache">true</prop>   
        <prop key="hibernate.c3p0.minPoolSize">5</prop>
        <prop key="hibernate.c3p0.maxPoolSize">20</prop>
      </props>
    </property>
</bean>

<bean id="baseDao" abstract="true" class="com.test.app.project.dao.BaseDAOImpl">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

<bean id="userDao" parent="baseDao" class="com.test.app.project.dao.UserDAOImpl">
</bean>

<bean id="userService" class="com.test.app.project.services.UserServiceImpl">
    <property name="userDao" ref="userDao" />
</bean>

<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

DAO 类中的 getAll 方法

public <T> List<T> getAll(final Class<T> type) {
        long startTime = System.nanoTime();
        List<T> afterGetAll = getSessionFactory().getCurrentSession().createSQLQuery("SELECT user_id,username,email,is_active FROM app_users")
                .addScalar("user_id", LongType.INSTANCE)
                .addScalar("username", StringType.INSTANCE)
                .addScalar("email", StringType.INSTANCE)
                .addScalar("is_active", IntegerType.INSTANCE)
                .setResultTransformer(Transformers.aliasToBean(UserModel.class)).list();
        //List<T> afterGetAll = getSessionFactory().getCurrentSession().createCriteria(type).list();
        long endTime = System.nanoTime();
        long duration = (endTime - startTime); 
        logger.info("============getAll=============== Execution Timestamp: " + duration/1000000 + "milliseconds");
        return afterGetAll;
    }

服务类调用上面的dao

@Transactional(propagation=Propagation.REQUIRES_NEW,isolation = Isolation.READ_COMMITTED)
@Service
public class UserServiceImpl implements UserService{
...
    @Override
    public <T> List<T> getAll(Class<T> type) {
        List<T> userList = userDao.getAll(type);
        return userList;
    }
...
}

也欢迎在配置/代码中提出任何可以提高性能的建议。先谢过

更新#1: 启用hibernate statistics后，我可以推断，由于以下统计，大部分时间都没有花在执行语句上。

2015-10-14 10:45:46 INFO  StatisticalLoggingSessionEventListener:275 - Session M
etrics {
    298847 nanoseconds spent acquiring 1 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    914957 nanoseconds spent preparing 1 JDBC statements;
    335661830 nanoseconds spent executing 1 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    0 nanoseconds spent performing 0 L2C puts;
    0 nanoseconds spent performing 0 L2C hits;
    0 nanoseconds spent performing 0 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and
0 collections);
    5735 nanoseconds spent executing 1 partial-flushes (flushing a total of 0 en
tities and 0 collections)
}

2015-10-14 10:45:46 INFO  AdminOperationController:51 - =======/admin/operation/
UserManagement Execution Timestamp:====== 3051milliseconds

事实证明，执行仅调用调用 DAO 的服务的 Controller 类与通过 hibernate 执行语句之间的执行时间几乎相差 10 倍

更新#2

我尝试添加一些毫秒时间戳来追踪哪个进程花费了大部分时间。后来发现大部分时间花在了将hibernate事务暴露为jdbc事务，每次服务操作后提交事务。统计发现日志如下所示

2015-10-15 18:00:13,768 DEBUG HibernateTransactionManager:448 - Preparing JDBC Connection of Hibernate Session [SessionImpl(PersistenceContext[entityKeys=[],collectionKeys=[]];ActionQueue[insertions=org.hibernate.engine.spi.ExecutableList@2b237512 updates=org.hibernate.engine.spi.ExecutableList@24db06de deletions=org.hibernate.engine.spi.ExecutableList@279febb9 orphanRemovals=org.hibernate.engine.spi.ExecutableList@742cd301 collectionCreations=org.hibernate.engine.spi.ExecutableList@2ad1223d collectionRemovals=org.hibernate.engine.spi.ExecutableList@81ee8c1 collectionUpdates=org.hibernate.engine.spi.ExecutableList@2542db11 collectionQueuedOps=org.hibernate.engine.spi.ExecutableList@483c4c33 unresolvedInsertDependencies=UnresolvedEntityInsertActions[]])]
2015-10-15 18:00:13,847 DEBUG HibernateTransactionManager:516 - Exposing Hibernate transaction as JDBC transaction [ConnectionHandle{url=jdbc:mysql://test, user=test, debugHandle=null, lastResetAgoInSec=18, lastUsedAgoInSec=18, creationTimeAgoInSec=18}]
2015-10-15 18:00:13,924 DEBUG SQL:109 - 
    /* dynamic native SQL query */ SELECT
        user_id,
        username,
        email,
        is_active 
    FROM
        app_users
2015-10-15 18:00:14,018 TRACE BasicExtractor:78 - extracted value ([user_id] : [BIGINT]) - [43]
...
...
2015-10-15 18:00:14,177 TRACE BasicExtractor:78 - extracted value ([username] : [VARCHAR]) - [username33]
2015-10-15 18:00:14,178 TRACE BasicExtractor:78 - extracted value ([email] : [VARCHAR]) - [ss@ss.com]
2015-10-15 18:00:14,178 TRACE BasicExtractor:78 - extracted value ([is_active] : [INTEGER]) - [0]
2015-10-15 18:00:14,178 TRACE BasicExtractor:78 - extracted value ([user_id] : [BIGINT]) - [136]
2015-10-15 18:00:14,179 TRACE BasicExtractor:78 - extracted value ([username] : [VARCHAR]) - [username34]
2015-10-15 18:00:14,179 TRACE BasicExtractor:78 - extracted value ([email] : [VARCHAR]) - [ss2@ss.com]
2015-10-15 18:00:14,180 TRACE BasicExtractor:78 - extracted value ([is_active] : [INTEGER]) - [0]
2015-10-15 18:00:14,283 INFO  BaseDAOImpl:117 - ============getAll=============== Execution Timestamp: 433milliseconds
2015-10-15 18:00:14,284 DEBUG HibernateTransactionManager:759 - Initiating transaction commit
2015-10-15 18:00:14,286 DEBUG HibernateTransactionManager:580 - Committing Hibernate transaction on Session [SessionImpl(PersistenceContext[entityKeys=[],collectionKeys=[]];ActionQueue[insertions=org.hibernate.engine.spi.ExecutableList@2b237512 updates=org.hibernate.engine.spi.ExecutableList@24db06de deletions=org.hibernate.engine.spi.ExecutableList@279febb9 orphanRemovals=org.hibernate.engine.spi.ExecutableList@742cd301 collectionCreations=org.hibernate.engine.spi.ExecutableList@2ad1223d collectionRemovals=org.hibernate.engine.spi.ExecutableList@81ee8c1 collectionUpdates=org.hibernate.engine.spi.ExecutableList@2542db11 collectionQueuedOps=org.hibernate.engine.spi.ExecutableList@483c4c33 unresolvedInsertDependencies=UnresolvedEntityInsertActions[]])]
2015-10-15 18:00:14,496 DEBUG HibernateTransactionManager:669 - Closing Hibernate Session [SessionImpl(PersistenceContext[entityKeys=[],collectionKeys=[]];ActionQueue[insertions=org.hibernate.engine.spi.ExecutableList@2b237512 updates=org.hibernate.engine.spi.ExecutableList@24db06de deletions=org.hibernate.engine.spi.ExecutableList@279febb9 orphanRemovals=org.hibernate.engine.spi.ExecutableList@742cd301 collectionCreations=org.hibernate.engine.spi.ExecutableList@2ad1223d collectionRemovals=org.hibernate.engine.spi.ExecutableList@81ee8c1 collectionUpdates=org.hibernate.engine.spi.ExecutableList@2542db11 collectionQueuedOps=org.hibernate.engine.spi.ExecutableList@483c4c33 unresolvedInsertDependencies=UnresolvedEntityInsertActions[]])] after transaction
2015-10-15 18:00:14,499 INFO  StatisticalLoggingSessionEventListener:275 - Session Metrics {
    21735 nanoseconds spent acquiring 1 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    10155810 nanoseconds spent preparing 1 JDBC statements;
    69653167 nanoseconds spent executing 1 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    11795265 nanoseconds spent performing 1 L2C puts;
    0 nanoseconds spent performing 0 L2C hits;
    69732 nanoseconds spent performing 1 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
    31394 nanoseconds spent executing 1 partial-flushes (flushing a total of 0 entities and 0 collections)
}
2015-10-15 18:00:14,639 INFO  AdminOperationController:49 - =======/admin/operation/UserManagement Execution Timestamp:====== 924milliseconds

初始化缓存

2015-10-15 18:00:22,410 DEBUG HibernateTransactionManager:516 - Exposing Hibernate transaction as JDBC transaction [ConnectionHandle{url=jdbc:mysql://test, user=test, debugHandle=null, lastResetAgoInSec=22, lastUsedAgoInSec=22, creationTimeAgoInSec=22}]
2015-10-15 18:00:22,417 INFO  BaseDAOImpl:117 - ============getAll=============== Execution Timestamp: 4milliseconds
2015-10-15 18:00:22,418 DEBUG HibernateTransactionManager:759 - Initiating transaction commit
2015-10-15 18:00:22,419 DEBUG HibernateTransactionManager:580 - Committing Hibernate transaction on Session [SessionImpl(PersistenceContext[entityKeys=[],collectionKeys=[]];ActionQueue[insertions=org.hibernate.engine.spi.ExecutableList@19acc826 updates=org.hibernate.engine.spi.ExecutableList@1e8843f5 deletions=org.hibernate.engine.spi.ExecutableList@425997c orphanRemovals=org.hibernate.engine.spi.ExecutableList@407f9e04 collectionCreations=org.hibernate.engine.spi.ExecutableList@7a5f39b0 collectionRemovals=org.hibernate.engine.spi.ExecutableList@1c49094 collectionUpdates=org.hibernate.engine.spi.ExecutableList@fefe574 collectionQueuedOps=org.hibernate.engine.spi.ExecutableList@4ec12ad8 unresolvedInsertDependencies=UnresolvedEntityInsertActions[]])]
2015-10-15 18:00:22,625 DEBUG HibernateTransactionManager:669 - Closing Hibernate Session [SessionImpl(PersistenceContext[entityKeys=[],collectionKeys=[]];ActionQueue[insertions=org.hibernate.engine.spi.ExecutableList@19acc826 updates=org.hibernate.engine.spi.ExecutableList@1e8843f5 deletions=org.hibernate.engine.spi.ExecutableList@425997c orphanRemovals=org.hibernate.engine.spi.ExecutableList@407f9e04 collectionCreations=org.hibernate.engine.spi.ExecutableList@7a5f39b0 collectionRemovals=org.hibernate.engine.spi.ExecutableList@1c49094 collectionUpdates=org.hibernate.engine.spi.ExecutableList@fefe574 collectionQueuedOps=org.hibernate.engine.spi.ExecutableList@4ec12ad8 unresolvedInsertDependencies=UnresolvedEntityInsertActions[]])] after transaction
2015-10-15 18:00:22,627 INFO  StatisticalLoggingSessionEventListener:275 - Session Metrics {
    19621 nanoseconds spent acquiring 1 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    0 nanoseconds spent preparing 0 JDBC statements;
    0 nanoseconds spent executing 0 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    0 nanoseconds spent performing 0 L2C puts;
    2170444 nanoseconds spent performing 1 L2C hits;
    0 nanoseconds spent performing 0 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
    19018 nanoseconds spent executing 1 partial-flushes (flushing a total of 0 entities and 0 collections)
}
2015-10-15 18:00:22,766 INFO  AdminOperationController:49 - =======/admin/operation/UserManagement Execution Timestamp:====== 425milliseconds

有没有人可以建议我应该如何改善这种情况？

最佳答案

请找到一些建议:

1. 将 hibernate.show_sql 设置为“false”，并确保 Hibernate 日志记录以尽可能低的日志级别运行。
2. 将延迟加载定义为首选关联加载策略。
3. 在查询和条件上设置@Transactional(readOnly = true)，返回的对象永远不会被修改。
4. 大多数查询都无法从缓存中获益，因此默认情况下，查询不会被缓存。要启用缓存，请调用 Query.setCacheable(true)。
5. 您可以激活 Hibernate Statistics 来分析性能问题(属性 hibernate.generate_statistics 设置为 true)。
6. 验证您在表格上有索引。

关于java - Hibernate 事务管理器性能问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33108413/