Optimized tactical queries need indexed access paths, such as UPI, NUPI, NUSI, USI, or a single row partition. The main goal is to have an execution plan with each step only delivering one or a few rows. We have to optimize the joins, i.e. minimize the number of AMPs involved in the join operations.
Tactical query performance does not improve with the number of Teradata nodes. Adding more nodes to your Teradata system will not have any impact on the performance of your single tactical query. Nevertheless, adding nodes to your system allows more tactical queries to be executed at the same time.