Do's and Dont's while using Sorted Input in Aggregator transformation

In general, follow this check list to ensure that you are handling aggregator with sorted inputs correctly:
1. Do not use sorted input if any of the following conditions are true:

a.The aggregate expression uses nested aggregate functions.
b.The session uses incremental aggregation.
c. Input data is data driven.
You select data driven for the Treat Source Rows as Session Property, or the Update Strategy transformation appears before the Aggregator transformation in the mapping.
If you use sorted input under these circumstances, the Informatica Server reverts to default aggregate behavior, reading all values before performing aggregate calculations.

Remember, when you are using sorted inputs, you pass sorted data through the Aggregator.
Data must be sorted as follows:
1. By the Aggregator group by ports, in the order they appear in the Aggregator transformation.
2. Using the same sort order configured for the session.
If data is not in strict ascending or descending order based on the session sort order, the Informatica Server fails the session.