DIMENSION INDEXING in POLARIS
If you had already attended an event on 4th Aug 22 by "Modelers Forum India" you would be knowing by now that there is a concept called "Dimension Indexing" in Polaris Engine. In this article we will try to explain what do we mean by Dimension Indexing
If you remember, that in Hyperblock any dimension (apart from Anaplan TIME and Anaplan VERSION) constitutes one BLOCK meaning every item of the dimension is within the same block where you can perform all the functions like SELECT, SUM, LOOKUP, FINDITEM etc. while that still holds good in Polaris but there is an additional concept that was born with Polaris and that is Dimension Indexing. It means that every member/item of the dimension is being indexed but the catch is that this indexing happens in groups (Power of 2) and not at an individual member/item level.Let's try to understand with this example.
If the list/dimension has one item in it that means Polaris would need 1 index for it, if there are 2 list items then Polaris would still need 1 because the grouping of items at indices is capped at 2 (Power of 2 to 1) at entry level. When the list items go from 3 to 4 (Power of 2 to 2) then the indices required are 2 . Moving on, if the list items go from 5 to 8 (Power of 2 to 3) then the indices required are 3 and if the list items range from 9 to 16(Power of 2 to 4)then the indices required, yes you guessed it right, are 4. So how do you know how many indices are required by Polaris to hold all these members/items of the list/dimension. Just apply the LOGARITHM function to the base of 2 and ROUNDUP to its highest integer or in other words it is the POWER of 2 which should be greater than the number of items/members in the list. I am attaching a sheet where I have tried to break it down for you - Please go through it and let me know if you have any questions.
So in order for us to work with Polaris it is absolutely necessary that the calculations stay under these two thresholds.
1.The maximum number of indices is 64 at each line item level.
2. The maximum number of cells is (2^64)-1 at each line item level and that is equal to 18,446,744,073,709,600,000 i.e., 18 Quintrillion 446 Quadrillion 744 Trillion 73 Billion 709 Million and 600 Thousand cells.