Hi

the diff between the select statment s this:
useing this:
"AND USER_DATA_FIELD_14 Like 'Y%"
has a complitly diff excution plan then the second option:
AND RTRIM(USER_DATA_FIELD_14,' ') = 'YES' .
in the last option you use index serch (if you have one) when you use like no index serch, more sorting to do (to make it simple). your problm is not size, but tunning of the where part in your select statment.