Overhead Costs of Referential Integrity
Overhead costs includes building the reference index subtables and inserting, updating, and deleting rows in the referencing and referenced tables. Overhead for inserting, updating, and deleting rows in the referencing table is similar to that of USI subtable row handling.
Teradata Database redistributes a row for each reference to the AMP containing the USI or reference index subtable entry. Processing differs after that, and most of the additional cost is in message handling.
When implementing tables with referential integrity, consider the following factors.