Transformations > Deduplicate transformation > Groups in duplicate analysis
  

Groups in duplicate analysis

A mapping that reads a Deduplication transformation may take a long time to run because of the number of data comparisons that the transformation must perform. The number of comparisons relates to the number of input fields that the transformation must analyze.
The following table shows the number of calculations that a mapping performs for different numbers of data values on a single field:
Number of data values
Number of comparisons
10,000
50 million
100,000
5,000 million
1 million
500,000 million
To reduce the time that the mapping takes to run, the transformation can organize the input records into groups. A group is a set of records that contain identical values on a field that you specify. When you perform duplicate analysis on grouped data, the transformation analyzes the field data on the records within each group. The transformation does not compare the records in one group with the records in another group. The groups reduce the overall number of comparisons that the transformation must perform without any meaningful loss of accuracy in the mapping analysis.
Consider the following rules and guidelines when you organize data into groups: