Forum Discussion
Dynamic RLS and LOOKUPVALUE vs Many to Many Join
Hi user131313 ,
Thank you for reaching out to Microsoft Fabric Community Forum.
Below are key points to help guide your decision :
1)LOOKUPVALUE() can slow down on large fact tables, especially in calculated columns.
2)LOOKUPVALUE Can cause performance issues on large datasets (especially in calculated columns)
3)Many to Many relationships can be faster, but only if the bridge table and related logic are clean and non-redundant.
4)In large models, prefer using measures instead of calculated columns, and test using Performance Analyzer.
5)Since you’ve already found a M:M solution that avoids LOOKUPVALUE():
6)Go with the Many to Many approach if It aligns with your data model structure.
7)Use LOOKUPVALUE() if the relationships aren’t easily modelled.8)test both approaches using DAX Studio or the Performance Analyzer in Power BI to see what works best in your scenario.
Regards,
Chaithanya.
Hi user131313 ,
As we haven’t heard back from you, we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?
If our response addressed, please mark it as Accept as solution and click Yes if you found it helpful.
Regards,
Chaithanya.
Hi, whilst I'm grateful for the response received. I was looking for some more clear guidance/decision making on which option to follow and which is recommended? But it is possible that there's no answer to this? I did find a resolution to using Many-to-Many in my scenario without LOOKUPVALUE() so my plan is to test out both approaches on a big data model and see which is faster.
Hi user131313 ,
Thank you for reaching out to Microsoft Fabric Community Forum.
Below are key points to help guide your decision :
1)LOOKUPVALUE() can slow down on large fact tables, especially in calculated columns.
2)LOOKUPVALUE Can cause performance issues on large datasets (especially in calculated columns)
3)Many to Many relationships can be faster, but only if the bridge table and related logic are clean and non-redundant.
4)In large models, prefer using measures instead of calculated columns, and test using Performance Analyzer.
5)Since you’ve already found a M:M solution that avoids LOOKUPVALUE():
6)Go with the Many to Many approach if It aligns with your data model structure.
7)Use LOOKUPVALUE() if the relationships aren’t easily modelled.8)test both approaches using DAX Studio or the Performance Analyzer in Power BI to see what works best in your scenario.
Regards,
Chaithanya.
