Complexity RLS - Help please!

[PedroModa]

Hi everyone, good evening! I need some help.

Recently, a user reached out saying he couldn’t use one of our Power BI reports. At first, I found it strange because he was the only one reporting issues — everyone else has always used the report normally. It’s a clean, well-optimized report following best practices, so it didn’t make sense that only he was experiencing such extreme slowness.

I did a video call with him and confirmed the issue: the report was practically unusable, nothing would load — and again, this happened only for him. Even worse, his slowness was consuming a huge amount of my Fabric capacity (I’m using Embedded).

I started investigating and found that the problem was related to the RLS roles he is assigned to. He is a manager, so he belongs to 25 different RLS roles, each one associated with a cost center. Currently, all these roles share the same particularity: each RLS rule contains two cost center codes (an old one and a new one due to a recent incorporation). For example:

• Rule 1: Old Code 1 OR New Code 1
• …and so on, up to the 25th rule.

After digging deeper, I noticed that using OR inside RLS significantly hurts performance — and it seems this is exactly what is breaking the report for this specific user.

I tested replacing OR with IN, but the performance was exactly the same, with no improvement at all.

My question is: how can I solve this?

I thought about switching to dynamic RLS using USERNAME(). However, two problems came up:

1. Manual maintenance: I would constantly need to add and remove people from this table. And it would become a huge table, since we have almost 1,000 employees.
2. Limited flexibility: this approach works well if I only need to filter by cost center. But if I need to hide information from another table (like “section”), I don’t think it would solve that (at least as far as I understand).

Questions:

• Has anyone faced something similar?
• Is there a more efficient way to handle multiple complex RLS roles?
• Is there a modeling approach that avoids this performance drop, especially when a user belongs to many RLS roles?

Any help is greatly appreciated. Thank you!

[amitchandak]

@PedroModa , When you use more than one role, they are treated as OR conditions. Therefore, we need to merge those roles into a single role. This means you must combine the conditions into one role if you want them to function as an AND condition