Aggregator Transformation

Aggregator Transformation is connected and active transformation used to perform calculations. Aggregate calculations means sums, averages, counts and so on.

Points To Remember :-
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If group by is not checked, by default integration service returns last row as a result.

If group by is checked integration service returns all the rows from the table.
If the sorted input is not checked data will not be correct order.

If the sorted input is checked and sorter transformations or order by clause is not used in source qualifier then session would fail with error as 'expecting keys to be descending' 

Group by port and sorter transformation (or) order by clause in source qualifier should be on same port otherwise the session fails for the error as before.


Cache files created:-
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There are 2 different Cache files created with Aggregator transformation 

- Index Cache : Index Cache stores group values configured in group by ports.

- Data Cache : Data Cache stores calculations based on group by ports.

Steps to create an Aggregator transformation :-

- Go to the Mapping Designer, click on transformation in the toolbar and select create
- Select the Aggregator transformation, enter the name and click create. Then click Done. This will create an aggregator transformation without ports.
- To create ports, you can either drag the ports to the aggregator transformation or create in the ports tab of the aggregator.