Srikanth

• Mar 9th, 2017

 

A rollup component cannot be used as Scan , but vice versa i.e.., a scan component can be able to achieve the utput of a rollup component, In case of Rollup the finalise function exec is once per group so only 1 record per group we will get, But in case of scan Finalise function will be executed for each and every record, hence along with the other ouputs per group we can get the rollup output included in same.

Speedy

• Sep 22nd, 2017

 

As per my understanding, we cannot use rollup component as a scan component. The reason for this is Scan gets the cumulative data and can process the same number of output records as the number of input records, but that cant be the case with a rollup. Rollup will always perform a group by on the key mentioned thus reducing the number of records as one record per key column mentioned.

Jatin

• Apr 30th, 2018

 

Rollup will produce same number of columns as scan only in case when all the columns are selected as rollup key