When you push the DATE_DIFF function to Vertica, Vertica rounds the date difference value to the nearest integer. However, the PowerCenter Integration Service returns a float value. If you want the date difference to be treated as a float value in the Vertica database, you can disable pushdown optimization.
When you specify the format as Y and push the DATE_DIFF function to Vertica, Vertica calculates the difference in the dates in terms of number of days. However, the PowerCenter Integration Service calculates the difference in terms of number of years. If you want the difference value to be treated in terms of number of years, you can disable pushdown optimization.