刷新 Hibernate 会话需要很长时间

Question

我正在使用 Hibernate 5.2.8.Final 版本，我们需要从数据库中读取数百万数据并通过一些业务逻辑更新数据，因为我的数据库很大我想在之后提交数据我的批次大小已达到，所以我写了下面的代码

Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.getTransaction().begin();
Query<Object> query = session.createQuery(SQL, Object.class);
ScrollableResults scrollableResults = query.setCacheMode(CacheMode.IGNORE)
        .scroll(ScrollMode.FORWARD_ONLY);
int count = 0;
while (scrollableResults.next())
{
    Object object = (Object) scrollableResults.get(0);
    process(object)
    session.update(object);
    if (++count % batchSizeDeclare== 0)
    {
        session.flush();
        session.clear();
        LOGGER.info("Updated batch records");
    }
}
session.getTransaction().commit();
LOGGER.info("commited in Hibernate ");
}

下面是我的hibernate.cfg.xml文件

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <!-- Database connection settings -->
        <property name="connection.driver_class">com.microsoft.sqlserver.jdbc.SQLServerDriver</property>
        <property name="connection.url">jdbc:sqlserver://com;database=DEV</property>
        <property name="connection.username">user</property>
        <property name="connection.password">pass</property>

        <property name="hibernate.default_schema">schema</property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">5</property>

        <!-- SQL dialect -->
        <property name="dialect">org.hibernate.dialect.SQLServer2012Dialect</property>

        <!-- Disable the second-level cache -->
        <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <!-- <property name="show_sql">true</property> -->
        <!-- <property name="format_sql">true</property> -->

        <!-- Drop and re-create the database schema on startup -->
        <property name="hbm2ddl.auto">update</property>

        <!-- org.hibernate.HibernateException: No CurrentSessionContext configured! -->
        <property name="hibernate.current_session_context_class">thread</property>

        <property name="hibernate.jdbc.batch_size">100</property>

        <property name="hibernate.c3p0.min_size">5</property>
        <property name="hibernate.c3p0.max_size">20</property>
        <property name="hibernate.c3p0.timeout">300</property>
        <property name="hibernate.c3p0.max_statements">50</property>
        <property name="hibernate.c3p0.idle_test_period">3000</property>

        <mapping class="com.beans.Object" />

    </session-factory>
</hibernate-configuration>

下面是我的Object.java

 public class Object implements Serializable
    {
        private static final long serialVersionUID = 1L;

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        @Column(name = "ID", nullable = false, unique = true, updatable = false)
        private int id;
        private String filePath;

    private String fileName;
    private String mimeType;
    private double fileSize;
    // removed getters and setters

    }

一旦我的代码达到 session.flush()，它甚至在等待 30 分钟后也没有做任何事情。这是批量提交的正确方法吗？如何批量更新？

Answer 1

Once my code reached session.flush it is not doing anything even after waiting for 30 min.

相反，数据库似乎做得太多了。只是您看不到任何进展，因为数据库正在努力处理您提交的大量工作。

Is this the correct way to batch commit?

简短的回答是否。

您不必从数据库中获取数百万行。你有更好的选择：

您可以在数据库中进行处理，这样您就不用付出提取数据并通过网络发送的代价，只需在Java中进行处理。
如果您不能在数据库中处理它，那么您需要使用一次只能获取小块数据的批处理程序。这样，您甚至可以 parallelize the batch processing，这应该会减少整体处理时间。

刷新 Hibernate 会话需要很长时间

Flushing the Hibernate Session is taking a very long time

java

orm

hibernate

batch-processing

hibernate-batch-updates