Pushdown optimization is a concept using which you can push the transformation logic at the source or target database side. When you have the database table as the source, you can make use of SQL override to remove the logic written in the transformation. When you use SQL override, session performance is enhanced as processing the data at the database level is faster compared to processing the data in Informatica. You cannot remove all the transformations from the mapping. The part of transformation logic that can be pushed at source or target level is referred to as pushdown optimization.
Consider that you have a mapping with a sequence indicated as follows:
Source - Source Qualifier - Filter - Sorter - Aggregator - Expression - Lookup - Rank - Target
In filter transformation, we are filtering the data on a particular location. In sorter transformation,...
