To eliminate mapping bottlenecks, optimize the mapping.
Mapping-level optimization may take time to implement, but it can significantly boost performance. Focus on mapping-level optimization after you optimize the targets and sources.
Generally, reduce the number of transformations in the mapping and delete unnecessary links between transformations to optimize the mapping. Configure the mapping with the least number of transformations and expressions to do the most amount of work possible. Delete unnecessary links between transformations to minimize the amount of data moved. Optimize the transformations that are in the mapping. Be sure to follow best practices for mapping design.