Use the following rules and guidelines when pushing functions to Vertica:
If you use the YYY, MON, MONTH, HH12, and HH24 formats as part of the DATE_DIFF() function, the PowerCenter Integration Service does not push the function to Vertica.
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. For example, if the first date is 2000-08-15 and the second date is 1997-08-16, Vertica rounds the date difference value to 3, but the PowerCenter Integration Service returns 2.99731182795699. 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.