The Aggregator transformation requires all rows for a particular group to be processed within the same partition to ensure accurate calculations. The default partition type, Hash auto-keys, accomplishes this by using the defined group-by ports as the key for a hash function. The Data Integration Service then distributes rows to different partitions based on the resulting hash values. This guarantees that all records belonging to the same group are sent to the same partition. The fact that the input is sorted is a performance optimization that allows the transformation to use less memory, but it does not change the fundamental partitioning requirement for grouping.

A. Pass-through: This option does not redistribute data between partitions. It would lead to incorrect aggregate results unless the upstream transformation had already partitioned the data by the same group-by keys.

C. Not a valid partition points: The Aggregator is an active transformation and is one of the most common and valid points in a mapping to introduce a partition.

D. Based on the transformation scope: This is not a valid or recognized partition type within the Informatica PowerCenter platform. Partition types are specific algorithms like Hash, Key Range, or Round-Robin.

1. Informatica PowerCenter 10.5

Transformation Guide

Chapter 3: "Aggregator Transformation"

Section: "Partitioning the Aggregator Transformation"

p. 65.

Quote/Paraphrase: "When you add a partition point at the Aggregator transformation

the Workflow Manager sets the partition type to Hash Auto-Keys. The Data Integration Service uses the group by ports as the key to group data among partitions."

2. Informatica PowerCenter 10.5

Advanced Workflow Guide

Chapter 2: "Working with Partitions"

Section: "Hash Auto-Keys Partitioning"

p. 42.

Quote/Paraphrase: "The Data Integration Service uses hash auto-keys partitioning as the default for transformations with group-by ports

such as the Aggregator

Rank

and Sorter transformations. It groups data based on the ports that define the key."