There is a very simple import where the end-user checks a boolean for the items they want to keep in a subset and then runs an action that takes the boolean value to the list and updates the subset. Clean and straight.
However, user is not getting a peculiar error. Can you help me understand the reason behind this error:
Just to be clear, the user was adding only 3 items in the subset and not the cell count value being shown in the error.
Usually that happens when the cell count of any particular line item crosses 2.1-2.2 billion mark. Can you please check if the activation of three list items in a subset makes any line item (which is dimensioned by that subset) go beyond that mark.
@Misbah Thank you! that is new information for me. However, all the modules have a cell count of less than 2.2 billion so there cannot be a line item that heavy. Could there be any other reason that I can check?
As @Misbah stated, your line item is too big with dimensionality which causes the cell count of that line item to be greater than 2^31-1 (roughly 2.177 billion cells). Anaplan stores data (at the most detailed level) in blocks and we have 3 types of blocks: Time, Version, and Custom Lists. That block can't be bigger than the above threshold for a particular line item.
In the above picture, the data that is stored is in green (SKU by City by Channel).
Now, you may have seen cell calculations larger than 2.177 billion cells which can be explained in a couple different ways:
that cell count is aggregation of data, so if you turn Summaries off, that cell count will go down (remember, the threshold is at the most detailed or detailed "block" of data)
if the line item is using Time, again, the cell count is the aggregation of all time and that threshold is at the most granular level of time (be it at day, week, month, etc.). What this means, is the cell count of the most granular time period (day, week, month) has a limit of 2.177 billion cells, and since it is Time, the threshold resets for every granular "block", And since Versions are similar to Time, the same thresholds apply (Actual, Plan, Budget).
The above bullet also helps understand why using "Real" time is so important and beneficial.
So, to solve your issue, the cell count for that line item is too big and you need to remove dimensionality from it.
Honestly, I don't know the "why" and how Michael came up with that exact threshold, there has to be some kind math behind it. And yes, it is at the block level. So remember, you have blocks for Time, Version, and Custom Lists. I say this because I can get more cells using real time and real versions than using "fake" versions or "fake" time because the fake time and fake versions go into the Custom List block.