Forum Discussion
Row Level Security with Partitions
Hi, gabriel23
In Power BI's import mode, when a user queries a specific partition data and applies row-level security (RLS), the Power BI engine applies partition filtering (such as Date = '2024-04') before applying RLS's CompanyID filtering. The engine directly targets the 202404's partition and scans only the data for that partition. RLS filtering to further filter CompanyID = 1 in the partition data.
Because partitions have physically split the data over time, the engine doesn't need to scan the entire table, only a subset of the target partitions, and performance is still efficient even if RLS is present.
If you want to use DAX Studio to analyze queries and observe the number of rows and partition filters for VERTIPAQ SCAN, you can capture queries in DAX Studio. Run the following DAX query:EVALUATE SUMMARIZE( FILTER(FactUsers, FactUsers[Date] >= "2024-04-01" && FactUsers[Date] <= "2024-04-30"), FactUsers[CompanyID], "TotalGrossCash", [TotalGrossCash] )
You can check the number of rows in VERTIPAQ SCAN in DAX Studio to see if only the rows of the target partition are scanned. Check the WHERE condition to confirm that the partition filtering (Date) and RLS filtering (CompanyID) are in effect at the same time. Check the SE CPU Time in Server Timings to check whether the scan time meets the partition data volume expectations.Alternatively, you can use DAX Studio's View AS function to simulate RLS to observe the situation. You can check the following link:
How to Get Your Question Answered Quickly
Best Regards
Yongkang Hua
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
Hi, gabriel23
In Power BI's import mode, when a user queries a specific partition data and applies row-level security (RLS), the Power BI engine applies partition filtering (such as Date = '2024-04') before applying RLS's CompanyID filtering. The engine directly targets the 202404's partition and scans only the data for that partition. RLS filtering to further filter CompanyID = 1 in the partition data.
Because partitions have physically split the data over time, the engine doesn't need to scan the entire table, only a subset of the target partitions, and performance is still efficient even if RLS is present.
If you want to use DAX Studio to analyze queries and observe the number of rows and partition filters for VERTIPAQ SCAN, you can capture queries in DAX Studio. Run the following DAX query:
EVALUATE
SUMMARIZE(
FILTER(FactUsers, FactUsers[Date] >= "2024-04-01" && FactUsers[Date] <= "2024-04-30"),
FactUsers[CompanyID],
"TotalGrossCash", [TotalGrossCash]
)
You can check the number of rows in VERTIPAQ SCAN in DAX Studio to see if only the rows of the target partition are scanned. Check the WHERE condition to confirm that the partition filtering (Date) and RLS filtering (CompanyID) are in effect at the same time. Check the SE CPU Time in Server Timings to check whether the scan time meets the partition data volume expectations.
Alternatively, you can use DAX Studio's View AS function to simulate RLS to observe the situation. You can check the following link:
How to Get Your Question Answered Quickly
Best Regards
Yongkang Hua
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
where can i see how many rows or segments or bytes it scanned? I only see the number of rows returned which doesn't tell me if it scanned the entire table or not.
