I have three fields badge number, termination date and status to update to Salesforce based on badge number.im using update strategy in mapping and on session level -upsert with external lookup field as badge_number_c and treat source rows as data driven(session properties). However we get only 50 records updated and 20000 records rejected as badge numbers not present in target and those 20 k records trying to insert and hence rejected(since we did not map all fields to form record in Salesforce as we only update).. for this error log it consuming lot of time and wf run time is high.
I tried to remove upsert and external lookup field but it throws error as I'd field missing.. 