If you filter rows from the mapping, you can improve efficiency by filtering early in the data flow. Use a filter in a customized data object to remove the rows at the source. The customized data object limits the row set extracted from a relational source.

To improve mapping performance, you can also use a Filter transformation to drop rejected rows from an Update Strategy transformation if you do not need to keep rejected rows.

Avoid using complex expressions in filter conditions. To optimize Filter transformations, use simple integer or true/false expressions in the filter condition.