我正在尝试使用 EclipseLink 优化我的 JPA 实现。 我已经添加了批处理操作。但它仍然需要大量时间来进行 50 000 次插入。使用带 JDBC 的原始 SQL 执行完全相同的插入所花费的时间是其 10 倍以上。

为了确保批处理操作确实有效，我使用 Wireshark 检查我的数据包，它没有使用批处理插入。

这是插入数据包之一:

它没有做:

INSERT INTO ENTITYCLASSTEST (LASTNAME, NAME) VALUES ('sfirosijfhgdoi 0', 'dsufius0'), ('sfirosijfhgdoi 0', 'dsufius0'), ('sfirosijfhgdoi 0', 'dsufius0'), ('sfirosijfhgdoi 0', 'dsufius0')... and so on

我原以为它会像上面那样做，但它是为每个数据包插入一行而不是为每个数据包插入多行。

这是我的实体类:

@Entity
public class EntityClassTest implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;
    private String lastname;

    public EntityClassTest() {
    }

    public EntityClassTest(Long id, String name, String lastname) {
        this.id = id;
        this.name = name;
        this.lastname = lastname;
    }

    public EntityClassTest(String name, String lastname) {
        this.name = name;
        this.lastname = lastname;
    }

    public Long getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getLastName() {
        return lastname;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setLastName(String lastname) {
        this.lastname = lastname;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof EntityClassTest)) {
            return false;
        }
        EntityClassTest other = (EntityClassTest) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "database.EntityClassTest [id=" + id + " ]";
    }

}

这是我的持久化方法，它接收一个 List 并持久化其中的所有对象。

public void insertListToTable(final String persistenceUnit, final List list) throws SQLException {
        final EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory(persistenceUnit);
        final EntityManager entityManager = entityManagerFactory.createEntityManager();
        final EntityTransaction transaction = entityManager.getTransaction();

        try {            
            final int listSize = list.size();
            transaction.begin();

            for (int i = 0; i<listSize; i++) { //Object object : list) {
                final Object object = list.get(i);
                entityManager.persist(object);

                if ( i % 500 == 0 ) { //500, same as the JDBC batch size defined in the persistence.xml
                    //flush a batch of inserts and release memory:
                    entityManager.flush();
                    entityManager.clear();
                }
            }
            transaction.commit();
        }
        catch(Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            throw new SQLException(e.getMessage());
        } 
        finally {
            entityManager.close();
        }
    }

还有我的 persistence.xml，我将 500 设置为批处理值，文件是:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="ExternalServer" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <!-- List of Entity classes -->
    <class>model.EntityClassTest</class>
    <properties>
      <property name="javax.persistence.jdbc.url" value="jdbc:mysql://myServer:3306/testdb?zeroDateTimeBehavior=convertToNull"/>
      <property name="javax.persistence.jdbc.user" value="testdbuser"/>
      <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
      <property name="javax.persistence.jdbc.password" value="myPassword"/>
      <property name="javax.persistence.schema-generation.database.action" value="create"/>

      <!-- Weaving -->
      <property name="eclipselink.weaving" value="static"/>
      <!-- SQL dialect / Database type -->
      <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
      <property name="eclipselink.target-database" value="MySQL"/>
      <!-- Tell the JPA provider to, by default, create the table if it does not exist. -->
      <property name="javax.persistence.schema-generation.database.action" value="create"/>
      <!-- No logging (For development change the value to "FINE") -->
      <property name="eclipselink.logging.level" value="OFF"/>
      <!-- Enable batch writing -->
      <property name="eclipselink.jdbc.batch-writing" value="JDBC"/>
      <!-- Batch size -->
      <property name="eclipselink.jdbc.batch-writing.size" value="500"/>

    </properties>
  </persistence-unit>
</persistence>

所以我的问题是，为什么不批量插入呢？根据我在 EclipseLink 网站和此处阅读的内容，我相信我已经对 EclipseLink 进行了很好的配置。

//////////////////////////编辑//////////////////////////

正如 Chris 的回答所建议的，我在 EntityClassTest 中将此值 @GeneratedValue(strategy = GenerationType.IDENTITY) 更改为 @GeneratedValue(strategy = GenerationType. SEQUENCE) 并重新运行测试，数据包将像以前一样发送(如我在上面发布的图片)。恐怕它没有解决我的问题。

///////////////////////////编辑 2///////////////////////

我已将 persistence.xml 文件中的日志记录级别更改为 FINEST，如下所示。

<property name="eclipselink.logging.level" value="FINEST"/>

这是生成的日志。我把它放在一个 pastebin 里，因为它很长。

http://pastebin.com/rKihCKMW

它似乎调用了很多次 Execute query InsertObjectQuery。

///////////////////////////编辑 3///////////////////////

这是我使用的每个组件的版本。

+-------------------------+------------------------------+
| Variable_name           | Value                        |
+-------------------------+------------------------------+
| innodb_version          | 5.6.12                       |
| protocol_version        | 10                           |
| slave_type_conversions  |                              |
| version                 | 5.6.12-log                   |
| version_comment         | MySQL Community Server (GPL) |
| version_compile_machine | x86_64                       |
| version_compile_os      | Win64                        |
+-------------------------+------------------------------+

Netbeans 8.0

EclipseLink (JPA 2.1)

mysql-connector-java-5.1.24.jar

///////////////////////////编辑 4///////////////////////

根据 CuriousMind 的回答，我将我的 EntityClassTest id 注释编辑为:

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator="id-seq-gen")
    @SequenceGenerator( name="id-seq-gen", sequenceName="ID_SEQ_GEN", allocationSize=500 )
    private Long id;

但这并没有解决我的问题，我仍然在每个数据包中插入一个(如上图所述)并且在 EclipseLink 日志中我得到:

[EL Fine]: sql: 2014-10-19 06:44:02.608--ClientSession(824177287)--Connection(1674390738)--Thread(Thread[main,5,main])--SELECT LAST_INSERT_ID()
[EL Finest]: sequencing: 2014-10-19 06:44:02.608--UnitOfWork(1985011414)--Thread(Thread[main,5,main])--assign sequence to the object (1.251 -> database.EntityClassTest [id=null ])
[EL Finest]: query: 2014-10-19 06:44:02.608--UnitOfWork(1985011414)--Thread(Thread[main,5,main])--Execute query InsertObjectQuery(database.EntityClassTest [id=null ])
[EL Finest]: query: 2014-10-19 06:44:02.608--ClientSession(824177287)--Thread(Thread[main,5,main])--Execute query ValueReadQuery(name="ID_SEQ_GEN" sql="SELECT LAST_INSERT_ID()")
[EL Fine]: sql: 2014-10-19 06:44:02.608--ClientSession(824177287)--Connection(1674390738)--Thread(Thread[main,5,main])--INSERT INTO ENTITYCLASSTEST (LASTNAME, NAME) VALUES (?, ?)
    bind => [sfirosijfhgdoi 2068, dsufius1034]
[EL Fine]: sql: 2014-10-19 06:44:02.608--ClientSession(824177287)--Connection(1674390738)--Thread(Thread[main,5,main])--SELECT LAST_INSERT_ID()
[EL Finest]: sequencing: 2014-10-19 06:44:02.608--UnitOfWork(1985011414)--Thread(Thread[main,5,main])--assign sequence to the object (1.252 -> database.EntityClassTest [id=null ])
[EL Finest]: query: 2014-10-19 06:44:02.608--UnitOfWork(1985011414)--Thread(Thread[main,5,main])--Execute query InsertObjectQuery(database.EntityClassTest [id=null ])
[EL Finest]: query: 2014-10-19 06:44:02.608--ClientSession(824177287)--Thread(Thread[main,5,main])--Execute query ValueReadQuery(name="ID_SEQ_GEN" sql="SELECT LAST_INSERT_ID()")
[EL Fine]: sql: 2014-10-19 06:44:02.608--ClientSession(824177287)--Connection(1674390738)--Thread(Thread[main,5,main])--INSERT INTO ENTITYCLASSTEST (LASTNAME, NAME) VALUES (?, ?)
    bind => [sfirosijfhgdoi 2244, dsufius1122]

等等……

最佳答案

您正在使用 GenerationType.IDENTITY 进行排序，这需要从每个插入语句中逐一检索 ID。尝试允许以 500 个为一组进行预分配的排序方案，您将看到改进: http://en.wikibooks.org/wiki/Java_Persistence/Identity_and_Sequencing#Identity_sequencing

关于java - EclipseLink 批量插入非常非常慢，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26416847/