How to filter date range with primefaces calendar? - jsf

Question

I filter columns in data table with prime faces dataTable showcase example
<p:column id="logStatus" filterBy="#{log.status}" headerText="status">
<h:outputText value="#{log.status}" />
</p:column>
<p:column filterBy="#{log.mbr}" headerText="mbr">
<h:outputText value="#{log.mbr}" />
</p:column>
Everything works fine when the key is released filters are sent to my DAO where I do some logic.
I don't know how to implement this with <p:calendar>
I want to pick dates from calendar and sand it to DAO in the same way as it works with filters I provided above
A column with calendar, I need two calendars in one column
<p:column filterBy="#{log.datumOd}" headerText="datumupisa od">
<f:facet name="filter">
<p:calendar id="datumOd" pattern="dd/MM/yyyy">
<p:ajax event="dateSelect" />
</p:calendar>
</f:facet>
<f:facet name="filter">
<p:calendar id="datumDo" pattern="dd/MM/yyyy">
<p:ajax event="dateSelect" />
</p:calendar>
</f:facet>
<h:outputText value="#{log.datumUpisa}" />
</p:column>
I need explanation how filterBy works? Should i use update, on complete and event ? I tried to use two columns and filterby dateFrom and dateTo, but events not working. It works if i pick dates and then filter by other filters ( from above ).
I will proivde more info and code if needed.