Multi-Row Formula Group By & Sorting

[Bonediggler]

Experts - 

I am using the multi-row formula to partition data by 2 dimensions and then do a row count within each partition, i.e.:

IF ISNULL([Row-1:filter_partition]) 
THEN 1
ELSE [Row-1:filter_partition] + 1
ENDIF

I am grouping by the 2 dimensions in the multi-row formula.  Initially I put a sort tool before the multi-row to sort by those dimensions so "filter_partition" would calculate correctly, but I just noticed if I remove the sort tool it still calculates correctly.

I can only assume this is because the multi-row formula sorts the data as per the group by fields.  Can someone confirm?  It is not mentioned in the online documentation.

Thank you!

[JosephSerpis · Accepted solution]

Yes grouping data in the Multi Row sorts data during the caculation of the tool. Users typically use a sort tool beforehand as they can see what order their data is in before it goes into the multi-row tool. 

[Bonediggler]

Thanks Joseph - any idea why this isn't included in the documentation?  It seems like a pretty fundamental feature of the tool, and eliminating the unnecessary pre-sort can have a big effect on performance when chugging large data sets.