Edição em DataTable PrimeFaces.

Olá, estou tentando utilizar o datatables do Primefaces, mas tenho dificuldades em entender porque ocorre várias chamadas no get que constrói a tabela e como corrigir isso.

view:

<h:form>
           <p:panel>     
                <p:dataTable value="#{datasbean.todasasdatas}" var="d"  editable="true" id="tabeladatas" 
                    emptyMessage="Não há datas Cadastradas">
                    <f:facet name="header">  
                        Lista de Datas 
                    </f:facet>

                    <p:ajax event="rowEditInit" listener="#{datasbean.iniciaredicao}"/>
                    <p:ajax event="rowEdit" listener="#{datasbean.alterar}" update=":form1:messages" />                     
                    <p:ajax event="rowEditCancel" listener="#{datasbean.cancelar}" update=":form1:messages" /> 

                    <p:column>
                        <f:facet name="header">  
                            <h:outputText value="Ano" />  
                        </f:facet>
                        <p:cellEditor>  
                            <f:facet name="output">  
                                <h:outputText value="#{d.tbano.ano}" />  
                            </f:facet>  
                            <f:facet name="input">  
                                <p:inputText value="#{datasbean.tbano.ano}" style="width:100%"/>
                            </f:facet>  
                        </p:cellEditor> 
                    </p:column>

                    <p:column>
                        <f:facet name="header">  
                            <h:outputText value="Descrição" />  
                        </f:facet>
                        <p:cellEditor>  
                            <f:facet name="output">  
                                <h:outputText value="#{d.descricao}" />  
                            </f:facet>  
                            <f:facet name="input">  
                                <p:inputText value="#{datasbean.dtdescricao}" style="width:100%"/>  
                            </f:facet>  
                        </p:cellEditor> 
                    </p:column>

                    <p:column>
                        <f:facet name="header">  
                            <h:outputText value="Inicio" />  
                        </f:facet>
                        <p:cellEditor>  
                            <f:facet name="output">  
                                <h:outputText value="#{d.datainicio.time}">
                                    <f:convertDateTime pattern="dd/MM/yyyy HH:mm:ss" timeZone="GMT-03:00"/> 
                                </h:outputText>  
                            </f:facet>  
                            <f:facet name="input">  
                                    <p:calendar id="datainicio" value="#{datasbean.datainicio}" pattern="dd/MM/yyyy HH:mm:ss" timeZone="GMT-03:00"/> 
                            </f:facet>  
                        </p:cellEditor>
                    </p:column>

                    <p:column>
                        <f:facet name="header">  
                            <h:outputText value="Termino" />  
                        </f:facet>
                        <p:cellEditor>  
                            <f:facet name="output">  
                                <h:outputText value="#{d.datafim.time}">
                                    <f:convertDateTime pattern="dd/MM/yyyy HH:mm:ss" timeZone="GMT-03:00"/> 
                                </h:outputText>  
                            </f:facet>  
                            <f:facet name="input">  
                                    <p:calendar id="datafim" value="#{datasbean.datafim}" pattern="dd/MM/yyyy HH:mm:ss" timeZone="GMT-03:00"/>

                            </f:facet>  
                        </p:cellEditor>
                    </p:column>
                    <p:column>
                        <f:facet name="header">  
                            <h:outputText value="Tipo" />  
                        </f:facet>
                        <p:cellEditor>
                            <f:facet name="output"><h:outputText value="#{d.tbtipo.descricao}" /></f:facet>
                            <f:facet name="input">
                               <h:selectOneMenu value="#{datasbean.tbtipo.id}" style="width:100%">
                                   <f:selectItems value="#{datasbean.listatipos}" var="tipo" itemLabel="#{tipo.descricao}" itemValue="#{tipo.id}" />
                               </h:selectOneMenu>
                           </f:facet>
                        </p:cellEditor>   
                    </p:column>


                    <p:column headerText="Editar" style="width:70px">  

                        <p:rowEditor/>

                    </p:column>

                    <p:column headerText="Remover" style="width:70px">
                     <p:commandLink styleClass="ui-icon ui-icon-trash" action="#{datasbean.remover}" value="Remover" update="tabeladatas">                           
                                <f:setPropertyActionListener target="#{datasbean.tbdata}" value="#{d}" /> 
                     </p:commandLink>                              
                   </p:column> 

                </p:dataTable>
            </p:panel>
             </h:form>

MB:

@ManagedBean(name="datasbean")
@ViewScoped
public class CalendarioBean implements Serializable{
/** omitido **/
private List<Tbdata> todasasdatas;

/** omitido **/

public List<Tbdata> getTodasasdatas() {
        return new TbdataDaoImpl().listarDatas();
    }

    public void setTodasasdatas(List<Tbdata> todasasdatas) {
        this.todasasdatas = todasasdatas;
    }
/** omitido **/

Quando aciono a edição de uma linha da tabela o método "getTodasasdatas "que constrói a tabela é chamado diversas vezes . Isso é normal ? Ou existe alguma configuração que falta adicionar?

Obrigado.