JDBCBatchItemWriter not receiving the List for batch update - spring

Question

I'm a new bee to spring batch. My requirement is to fetch records from a DB table, process them(each record can be processed independently so i'm partitioning and using a task executor) and then update the status column in the same table based on processing status.
Simplified version of my code is below.
Item Reader (My custom column partitioner will decide the min & max value below):
<bean name="databaseReader" class="org.springframework.batch.item.database.JdbcCursorItemReader" scope="step">
<property name="dataSource" ref="dataSource"/>
<property name="sql">
<value>
<![CDATA[
select id,user_login,user_pass,age from users where id >= #{stepExecutionContext['minValue']} and id <= #{stepExecutionContext['maxValue']}
]]>
</value>
</property>
<property name="rowMapper">
<bean class="com.springapp.batch.UserRowMapper" />
</property>
<property name="verifyCursorPosition" value="false"/>
</bean>
Item Processor:
<bean id="itemProcessor" class="com.springapp.batch.UserItemProcessor" scope="step"/>
....
public class UserItemProcessor implements ItemProcessor<Users, Users>
{
#Override
public Users process(Users users) throws Exception {
// do some processing here..
//update users status
//users.setStatus(users.getId() + ": Processed by :" + Thread.currentThread().getName() + ": Processed at :" + new GregorianCalendar().getTime().toString());
//System.out.println("Processing user :" + users + " :" +Thread.currentThread().getName());
return users;
}
}
Item Writer:
<bean id="databaseWriter" class="org.springframework.batch.item.database.JdbcBatchItemWriter">
<property name="dataSource" ref="dataSource" />
<property name="sql">
<value>
<![CDATA[
update users set status = :status where id= :id
]]>
</value>
</property>
<property name="itemSqlParameterSourceProvider">
<bean class="org.springframework.batch.item.database.BeanPropertyItemSqlParameterSourceProvider" />
</property>
</bean>
Step configuration:
<batch:job id="usersJob">
<batch:step id="stepOne">
<batch:partition step="worker" partitioner="myColumnRangepartitioner" handler="partitionHandler" />
</batch:step>
</batch:job>
<batch:step id="worker" >
<batch:tasklet transaction-manager="transactionManager">
<batch:chunk reader="databaseReader" writer="databaseWriter" commit-interval="5" processor="itemProcessor" />
</batch:tasklet>
</batch:step>
<bean id="asyncTaskExecutor" class="org.springframework.core.task.SimpleAsyncTaskExecutor" />
<bean id="partitionHandler" class="org.springframework.batch.core.partition.support.TaskExecutorPartitionHandler" scope="step">
<property name="taskExecutor" ref="asyncTaskExecutor"/>
<property name="step" ref="worker" />
<property name="gridSize" value="3" />
</bean>
Since i have specified the commit interval as 5 my understanding is that when 5 items are processed by a partition, it will call JDBCItemWriter with a List of 5 Users object to perform a batch JDBC update. However with the current setup, i'm receiving 1 User object at a time during batch update.
Is my understanding above correct or am i missing any step/configuration ?
Note: I'm using HSQL file based database for testing.
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="org.hsqldb.jdbc.JDBCDriver"/>
<property name="url" value="jdbc:hsqldb:file:C://users.txt"/>
<property name="username" value="sa"/>
<property name="password" value=""/>
</bean>