Lazy DataTable rendering is very slow - performance

Question

Environment:
PrimeFaces 5.1
Mojarra 2.2.2
Spring 4.0.2
Problem:
I use a p:dataTable with lazy=true and I have implemented a LazyDataModel.
All works perfectly well (pagination, filtering, etc.), but it is very slow...
The load method is called, it performes the call to the DB and returns in 3sec max. But after that, it takes up to 20sec for the page to load (render?)...
For information, the page loads through ajax: a listener give informations to the LazyModel (setters), then change the page to insert (ui:insert, value stored in the controller), and finally update the form (update=":form").
After debugging it seems that I have no control on this...
Code:
<p:dataTable id="storeTable"
value="#{dashboard.stores}"
var="store"
lazy="true"
paginator="true" rows="30"
paginatorTemplate="{FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink}"
paginatorPosition="bottom">
...
<!-- Columns -->
...
<c:forEach var="date" items="#{dashboard.days}">
<c:set var="day" value="#{store.getDay(date)}"/>
<p:column styleClass="store-day open-#{store.isAmOpen(date.date)} store-day-available-#{store.isAvailable(date.date)} #{store.storeKey} #{day.date.time} am"
width="30">
<h:outputText value=" " title="#{day.amComment}" />
<h:outputText styleClass="store" value="#{store.storeKey}" style="display: none" />
<h:outputText styleClass="date" value="#{day.date.time}" style="display: none" />
<h:outputText styleClass="am_pm" value="am" style="display: none" />
</p:column>
<p:column styleClass="store-day open-#{store.isPmOpen(date.date)} store-day-available-#{store.isAvailable(date.date)} #{store.storeKey} #{day.date.time} pm"
width="30">
<h:outputText value=" " title="#{day.pmComment}" />
<h:outputText styleClass="store" value="#{store.storeKey}" style="display: none" />
<h:outputText styleClass="date" value="#{day.date.time}" style="display: none" />
<h:outputText styleClass="am_pm" value="pm" style="display: none" />
</p:column>
</c:forEach>
</p:dataTable>
Relevant code of the controller:
#Controller("dashboard")
#Scope("session")
public class DashboardController implements Serializable {
private static final long serialVersionUID = 1971543164359627877L;
private LazyStoreWebModel stores;
// Some more attributes
#PostConstruct
public void postCtr() {
stores = new LazyStoreWebModel(restit);
update();
}
private void updateGroupList() {
groupList.clear();
groupList.addAll(groupDao.findByCountry(countryFilter));
}
public void updateStoreChainTypeList() {
storeChainTypeList.clear();
storeChainTypeList.addAll(storeTypeDao.findByCountry(countryFilter));
}
public void updateStoreZoneList() {
storeZoneList.clear();
storeZoneList.addAll(storeZoneDao.findByCountryAndChainType(
countryFilter, chainTypeFilter));
}
public void updateStoreRegionList() {
storeRegionList.clear();
if (storeZoneFilter != null) {
storeRegionList.addAll(storeRegionDao.findByCountryAndZone(
countryFilter, storeZoneFilter));
}
}
public void updateDays() {
days.clear();
days.addAll(calendar.generateListDateFromMonthAndYear(
yearFilter, monthFilter.getCode()));
stores.setYear(yearFilter);
stores.setMonth(monthFilter.getCode());
Collections.sort(days);
}
public void update() {
updateGroupList();
updateStoreChainTypeList();
updateStoreZoneList();
updateStoreRegionList();
updateDays();
stores.setCountry(countryFilter);
stores.setChainType(chainTypeFilter);
stores.setRegion(storeRegionFilter);
stores.setZone(storeZoneFilter);
}
public LazyDataModel<StoreWeb> getStores() {
return stores;
}
}
The LazyDataModel
public class LazyStoreWebModel extends LazyDataModel<StoreWeb> {
private static final long serialVersionUID = -4318420518897167924L;
private RestitService restit;
private Country country;
private StoreChainType chainType;
private StoreZone zone;
private StoreRegion region;
private Integer storeIntFlagFilter;
private Integer year;
private Integer month;
public LazyStoreWebModel(RestitService restit) {
this.restit = restit;
}
#Override
public StoreWeb getRowData(String key) {
try {
return restit.visualisationStoreById(key, year, month);
} catch (CalendarException e) {
e.printStackTrace();
} catch (NotExistStoreException e) {
e.printStackTrace();
}
StoreWeb sto = new StoreWeb();
sto.setStoreDesc("Should be null");
sto.setStoreKey("NULL:" + key);
return sto;
}
#Override
public Object getRowKey(StoreWeb sto) {
return sto.getStoreKey();
}
#Override
public List<StoreWeb> load(int first, int pageSize, String sortField,
SortOrder sortOrder, Map<String, Object> fieldFilters) {
List<StoreWeb> result = new ArrayList<StoreWeb>();
Map<String, Object> mainFilters = new HashMap<String, Object>();
mainFilters.put(RestitService.COUNTRY_KEY, country);
mainFilters.put(RestitService.CHAIN_TYPE_KEY, chainType);
mainFilters.put(RestitService.ZONE_KEY, zone);
mainFilters.put(RestitService.REGION_KEY, region);
mainFilters.put(RestitService.INT_FLAG_KEY, storeIntFlagFilter);
mainFilters.put(RestitService.YEAR_KEY, year);
mainFilters.put(RestitService.MONTH_KEY, month);
try {
result.addAll(restit.load(first, pageSize, sortField, sortOrder,
mainFilters, fieldFilters));
} catch (CalendarException e) {
e.printStackTrace();
} catch (NotExistStoreException e) {
e.printStackTrace();
}
setRowCount(restit.count(mainFilters, fieldFilters));
return result;
}
}
The restit attribute do the calls to the DB.
Any idea?
Thanks.
Edits:
Added relevant code of the controller
Added code of the LazyDataModel
Added code inside the HTML: Problem seems to come from the amount of columns (60+), more precisely from the quantity of attribute access done to build those.