[Feature Request / Performance]DirectQuery table is extremely slow when just draggin

[ysc625298945]

Dear Power BI Team,

I’m facing a critical performance issue when using Power BI Desktop + DirectQuery (connected to Hologres/PostgreSQL-compatible) for ad-hoc analysis. The problem is NOT on the database side, but caused by Power BI auto-generated DAX and Formula Engine (FE).

Steps to Reproduce (No custom DAX at all)

1. Use DirectQuery over a data warehouse table.
2. Simply drag dimension fields into a Table visual: Date, Region, Warehouse, Delivery Method, Express, Province, City, etc.
3. No measures, no complex calculations – just viewing details.

Issue

• Refresh time: ~58 seconds
• UI freezes completely
• Database SQL execution time: only ~1 seconds (returns 130k rows)
• 99% time spent on Power BI FE, not query

Root Cause (Proven by DAX Studio & ServerTimings)

1. Power BI auto-generates heavy DAX:
   • SUMMARIZECOLUMNS + ROLLUPADDISSUBTOTAL (forced subtotals/grand total)
   • Full sorting across many fields + TOPN(1000001)
2. DirectQuery pushes data warehouse-level aggregation to the single-threaded frontend FE
3. Even with Totals turned off, the query remains too heavy for ad-hoc usage

User Impact (Common enterprise scenario)

• Business users drag fields flexibly for ad-hoc analysis
• No DAX, no modeling – just simple tables
• DirectQuery must support lightning-fast detail queries

Suggested Optimizations

1. Optimize auto-generated DAX for detail tables
   • Do NOT generate ROLLUP/ISSBTOTOTAL by default
   • Reduce unnecessary sorting & nesting
2. Lightweight DirectQuery for details
   • Push down simple SELECT instead of heavy grouping
   • Add pagination / row limit by default
3. Isolate performance
   • Separate detail table rendering from heavy FE computation

Please fix this issue so DirectQuery can support fast, ad-hoc, drag-and-drop analysis for real business users.Thank you!servertimingstable

[ysc625298945]

Hi Tom,

Thanks a lot for your help! I really appreciate you guiding me to the official Ideas platform. I’ll post my request there now and share the link if needed.

Have a great day! 😊

[v-ssriganesh]

Hello  @ysc625298945,
Thank you for the update.

Could you please confirm whether you have submitted this suggestion to the Ideas Forum? If so, we would appreciate it if you could share the link here. This may help other community members who have similar feedback discover and support the idea.

Thank you for being a part of the Microsoft Fabric Community, and we appreciate your continued engagement in the community forums.

Best regards,
Ganesh Singamshetty

[TomMartens]

Hey @ysc625298945 ,

you need to raise the feature request here: ideas.powerbi.com

Regards,
Tom