15.00 - Row Partition Elimination - Teradata Database

Teradata Database Design

Teradata Database
User Guide

Row Partition Elimination

Row partition elimination is a method for enhancing query performance against row partitioned tables by skipping row partitions that do not contain rows that meet the search conditions of a query. Row partition elimination is an automatic optimization in which the Optimizer (or, in the case of dynamic row partition elimination, the AMP software) determines, based on query conditions and a row partitioning expression, that some partitions for that partitioning expression cannot contain qualifying rows; therefore, those row partitions can be skipped during a file scan.

Note that the Optimizer cannot exert all of the optimizations that are possible for each of the individual types of row partition elimination.

Partitions that are skipped for a particular query are called eliminated row partitions.

When there are multiple partitioning expressions, Teradata Database combines row partition elimination at each of the levels to further reduce the number of data subsets that need to be scanned. For most applications, the greatest benefit of row partitioning is obtained from row partition elimination.