Using a DB2 for z/OS source database, a 200 million row source table with 30 million distinct
values must be aggregated to calculate the average value of two column attributes. What would
provide optimal performance while satisfying the business requirements?
A.
Select all source rows using a DB2 API stage. Aggregate using a Sort Aggregator.
B.
Using custom SQL with AVG functions and a DISTINCT clause,select all source rows using a
DB2 Enterprise stage.
C.
Using custom SQL with an ORDER BY clause based on key columns,select all source rows
using the DB2 API stage. Aggregate using a Hash Aggregator.
D.
Select all source rows using a DB2 Enterprise stage,use a parallel Sort stage with the specified
sort keys,calculate the average values using a parallel Transformer with stage variables and
output link constraints.
Explanation: