When I use below query with 'EXCEPT' clause it the "OLD DB Source control" in "Data Flow" task it is not getting invoked. But it shows the DFT as successful.
--To extract the new records; Compare the Staging table with main table
SELECT GlobalServerID, Account, ArchiveName, Size, VolumeID FROM dbo.FactStaging
EXCEPT
SELECT GlobalServerID, Account, ArchiveName, Size, VolumeID FROM dbo.Fact
Krishna