Is deltaQuery mandatory ?

Is deltaQuery mandatory in data-config.xml ?

I did it like this :
<entity name="residential" query="select * from tsunami.consumer_data_01 where state='MA' and  rownum <= 5000"
                deltaQuery="select  LEMSMATCHCODE, STREETNAME from residential where last_modified > '${dataimporter.last_index_time}'">
 
Then my manager come and said we don't need it, this is only for incremental.
I took off the line that start with deltaQuery, now in :

http://localhost:8983/solr/#/db/dataimport//dataimport


entity is empty, when I click the button Exwcute, nothing happened,

thanks.