Question

I’m using the latest EclipseLink version with MySQL 5.5 (table type InnoDB). I’m inserting about 30900 records (which could be also more) at a time.
The problem is, that the insert performance is pretty poor: it takes about 22 seconds to insert all records (compared with JDBC: 7 seconds). I’ve read that using batch writing should help – but doesn’t!?

@Entity
public class TestRecord {

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

    public int test;
}

The code to insert the records:

factory = Persistence.createEntityManagerFactory("xx_test");
EntityManager em = factory.createEntityManager();

em.getTransaction().begin();

for(int i = 0; i < 30900; i++) {
    TestRecord record = new TestRecord();
    record.test = 21;
    em.persist(record);
}

em.getTransaction().commit();
em.close();

And finally my EclipseLink configuration:

<persistence-unit name="xx_test" transaction-type="RESOURCE_LOCAL">
    <class>com.test.TestRecord</class>

    <properties>
        <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
        <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/xx_test" />
        <property name="javax.persistence.jdbc.user" value="root" />
        <property name="javax.persistence.jdbc.password" value="test" />

        <property name="eclipselink.jdbc.batch-writing" value="JDBC" />
        <property name="eclipselink.jdbc.cache-statements" value="true"/>   

        <property name="eclipselink.ddl-generation.output-mode" value="both" />
        <property name="eclipselink.ddl-generation" value="drop-and-create-tables" />

        <property name="eclipselink.logging.level" value="INFO" />
    </properties>
</persistence-unit>

What I’m doing wrong? I’ve tried several setting, but nothing seems the help.
Thanks in advance for helping me! 🙂

-Stefan

---

Another thing is to add ?rewriteBatchedStatements=true to the data URL used by the connector.

This caused executing about 120300 inserts down to about 30s which was about 60s before.

Answer 1

@GeneratedValue(strategy = GenerationType.IDENTITY)

Switch to TABLE sequencing, IDENTITY is never recommended and a major performance issue.

See,
http://java-persistence-performance.blogspot.com/2011/06/how-to-improve-jpa-performance-by-1825.html

I seem to remember that MySQL may not support batch writing without some database config as well, there was another post on this, I forget the url but you could probably search for it.