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Hibernate : Bulk Insert/Batch Insert

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This tutorial contains description of Hibernate bulk insertion(Batch insertion)

Hibernate : Bulk Insert/Batch Insert

This tutorial contains description of Hibernate bulk insertion(Batch insertion)

Hibernate Batch Insertion :

In Hibernate Bulk Insertion concept came into existence when you need to insert large number of records into your database.
Here is simple code to insert large amount of records(suppose 100000 records)

 

Session session = SessionFactory.openSession();
Transaction tx = session.beginTransaction();
for ( int i=0; i<100000; i++ ) {
Student student= new Student (.....);
session.save(student);
}
tx.commit();
session.close();

By default, Hibernate will cache all the persisted objects in the session-level cache
so finally our application will show exception OutOfMemoryException around the 50,000th row.
This is big problem in insertion of bulk data. For solving this problem you can use batch insertion with Hibernate.

Batch Insertion is an important and powerful concept of Hibernate and very useful when you are inserting data in large amount
or importing data from other systems in batch.

For using batch processing feature, just set batch size as 20 or 50 depending on object size.This will tell to the hibernate container that every X rows to be inserted as batch.
You need to do bit changes in your code to implement this concept in your application.

ession session = SessionFactory.openSession();
Transaction tx = session.beginTransaction();
for ( int i=0; i<100000; i++ ) {
Student student = new Student (.....);
session.save(student);
if( i % 50 == 0 ) { // Same as the JDBC batch size
//flush a batch of inserts and release memory:
session.flush();
session.clear();
}
}
tx.commit();
session.close();

When you are making new objects persistent flush() and then clear() the session regularly in order to control the size of the first-level cache.

Example : In this example we are adding 100000 student records. It is an example of bulk insertion. we use batch insertion for inserting the records.

Hibernate.cfg.xml -

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate_examples</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<property name="hibernate.jdbc.batch_size">50</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">none</property>
<mapping class="net.roseindia.table.Student"/>
</session-factory>

</hibernate-configuration>

Main Class code HibernateBatchInsertion.java -

package net.roseindia.main;

import net.roseindia.table.Student;
import net.roseindia.util.HibernateUtil;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class HibernateBatchInsertion {
public static void main(String args[]) {
Session session = HibernateUtil.getSessionFactory().openSession();
Transaction transaction = null;
Integer roll = null;
try {
transaction = session.beginTransaction();
for (int i = 1; i < 100000; i++) {
roll = i;
String name = "Student" + i;
String course = "Course" + i;
Student student = new Student(roll, name, course);
session.save(student);
if (i % 50 == 0) {
session.flush();
session.clear();
}
}
transaction.commit();

session.close();
} catch (HibernateException e) {
e.printStackTrace();
}
}
}

Click here to download complete source code

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Posted on: August 18, 2012

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