Nice article.

Consider adding the checksum column as an INCLUDE column to the PK index on the table. Your milage may vary because:

1) The lookup transformation component only needs to read the PK index, not the actual data rows. [good for this process.]

2) The PK index is larger because of the checksum values. [a minus--hurts storage and any access using the PK.]

3) The PK index entry must be updated with a new checksum value whenever the data gets updated. Since the checksum value is always the same size, this will not fragment the index pages unless you use the "update trigger sets checksum column to null" idea. [a minus for any process that updates the data.]