DataModel annotation and ajax refresh

[dxxvi]

I don't understand why the db was hit for every single ajax request.

This is my SFSB:

@Stateful
@Name("employees")
@Scope(ScopeType.CONVERSATION)         // cannot be page-scoped
public class EmployeesImpl implements Employees {
    @Logger private Log log;

    @PersistenceContext private EntityManager entityManager;

    @DataModel(value="allEmployees", scope=ScopeType.PAGE) protected List<Employee> allEmployees;

    private Employee selectedEmployee;

    public void findAllEmployees() {
        allEmployees = entityManager.createQuery("select e from Employee e").getResultList();
    }

    public void selectEmployee(Employee e) {
        selectedEmployee = e;
    }

    public void selectEmployee1() {
        log.debug("hic hic hic");
    }

My test.xhtml:

<a4j:form>
    <h:dataTable value="#{allEmployees}" var="employee" width="840">
        <h:column>
            <f:facet name="header">ID</f:facet>
            <a4j:commandLink value="#{employee.id}" action="#{employees.selectEmployee1}"/>
            <h:outputText value="&#160;(call a non-parameter method)" style="font-style: italic;"/>
        </h:column>
        <h:column>
            <f:facet name="header">First Name</f:facet>
            <a4j:commandLink value="#{employee.firstName}" action="#{employees.selectEmployee(employee)}"/>
        </h:column>
    </h:dataTable>
</a4j:form>

My pages.xml:

<page view-id="/test.xhtml" action="#{employees.findAllEmployees}" />

Clicking on both <a4j:commandLink> causes a hit to the db.

I think, those clicks create ajax requests only. So, why is the method findAllEmployees executed for every single request?