Setting defaultRowPrefetch has no effect on query - spring

Question

I've got a weird issue with using Spring JDBC + Oracle 10g. Here's my dataSource config:
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="oracle.jdbc.OracleDriver" />
<property name="url" value="jdbc:oracle:thin:#localhost:1521:XE" />
<property name="username" value="admin" />
<property name="password" value="admin" />
<property name="validationQuery" value="SELECT 1 FROM DUAL"/>
<property name="testOnBorrow" value="true"/>
<property name="connectionProperties" value="defaultRowPrefetch=1000" />
</bean>
At first, I thought the connectionProperties value was being set but as I fine-tuned the query in SQL Developer (cost went from 3670 to 285 and plan explain went from :45 to :03), the time in the application never fluctuated from the original 15 seconds. Removing the connectionProperties setting had no effect. So, what I did was this:
DAO class
private List<Activity> getAllActivitiesJustJDBC() {
String query = "select * " + "from activity a, work_order w "
+ "where a.ac_customer = 'CSC' "
+ "and w.wo_customer = a.ac_customer "
+ "and a.ac_workorder = w.wo_workorder ";
long startTime = System.currentTimeMillis();
List<Activity> activities = new ArrayList<Activity>();
try {
Connection conn = jdbcTemplate.getDataSource().getConnection();
PreparedStatement st = conn.prepareStatement(query);
st.setFetchSize(1000);
ResultSet rs = st.executeQuery();
ActivityMapper mapper = new ActivityMapper();
while (rs.next()) {
Activity activity = mapper.mapRow(rs, 1);
activities.add(activity);
}
} catch (Exception ex) {
ex.printStackTrace();
}
System.out.println("Time it took...."
+ (System.currentTimeMillis() - startTime));
System.out.println("Number of activities = " + activities.size());
return activities;
}
This time, the time it took to fetch 11,115 rows took on average 2 seconds. The key statement is the setFetchSize(1000). So....I like option #2 but do I need to close the connection or is Spring handling this for me? In option #1, I would use the jdbcTemplate to call the query method, passing in the parameterized query and the BeanPropertyRowMapper instance using my data object and then returning the List.

Answer 1

Ok from looking at other questions similar to this one, I do need to close out the connection starting with the result set, then statement, and then the connection using a finally. I also remembered (from the days before Spring) I needed to wrap all that around a try/catch and then not really do anything if an exception occurs closing a connection.
FYI, I wonder if there's a way to set the fetch size when defining the datasource using Spring.
Here's the final method:
private List<Activity> getAllActivitiesJustJDBC() {
String query = "select * " + "from activity a, work_order w "
+ "where a.ac_customer = 'CSC' "
+ "and w.wo_customer = a.ac_customer "
+ "and a.ac_workorder = w.wo_workorder ";
long startTime = System.currentTimeMillis();
List<Activity> activities = new ArrayList<Activity>();
Connection conn = null;
PreparedStatement st = null;
ResultSet rs = null;
try {
conn = jdbcTemplate.getDataSource().getConnection();
st = conn.prepareStatement(query);
st.setFetchSize(1000);
rs = st.executeQuery();
while (rs.next()) {
activities.add(ActivityMapper.mapRow(rs));
}
} catch (Exception ex) {
ex.printStackTrace();
}
finally {
try {
rs.close();
st.close();
conn.close();
}
catch (Exception ex){
//Not much we can do here
}
}
System.out.println("Time it took...."
+ (System.currentTimeMillis() - startTime));
System.out.println("Number of activities = " + activities.size());
return activities;
}