Report loading time is increased

[yogita_2025]

Hi, 

I have published my reports on client's workspace. The reports are using a semantic model in that workspace for as dataset. The semantic model is connected to databricks. I have noticed that for 2 hours in a day while we validate the reports take very long to get loaded. After some time the get back to their normal loading time. What can be reason for that.

[rohit1991]

Hi @yogita_2025 ,

The slow report loading you’re experiencing during specific hours is most likely due to high resource usage or workload spikes on the Databricks cluster your semantic model connects to. Since your Power BI reports rely on a live connection, any increase in concurrent jobs, user activity, or scheduled processes on Databricks during that time can delay query responses and impact report performance. To address this, it’s recommended to monitor Databricks cluster usage during the affected hours to identify bottlenecks, and consider enabling auto-scaling or increasing cluster size temporarily to handle peak loads.

On the Power BI side, using tools like Performance Analyzer can help pinpoint visuals or queries causing delays, while implementing optimizations such as aggregations, incremental refresh, or switching to import mode can significantly reduce query load and improve performance. If you are using Fabric (Premium) capacity, the Metrics app can also offer valuable insights into usage patterns and help diagnose service-level issues. Combining improvements in both your data source and report design should help stabilize and enhance the loading experience.

[v-pnaroju-msft]

Hi yogita_2025,

We are following up to see if your query has been resolved. Should you have identified a solution, we kindly request you to share it with the community to assist others facing similar issues.

If our response was helpful, please mark it as the accepted solution and provide kudos, as this helps the broader community.

Thank you.

[v-pnaroju-msft]

Hi yogita_2025,

We wanted to check in regarding your query, as we have not heard back from you. If you have resolved the issue, sharing the solution with the community would be greatly appreciated and could help others encountering similar challenges.

If you found our response useful, kindly mark it as the accepted solution and provide kudos to guide other members.

Thank you.

[v-pnaroju-msft]

Hi yogita_2025,

We have not received a response from you regarding the query and were following up to check if you have found a resolution. If you have identified a solution, we kindly request you to share it with the community, as it may be helpful to others facing a similar issue.

If you find the response helpful, please mark it as the accepted solution and provide kudos, as this will help other members with similar queries.

Thank you.

[v-pnaroju-msft]

Thankyou, @BhavinVyas3003, for your response.

Hi @yogita_2025,

We appreciate your inquiry on the Microsoft Fabric Community Forum.

Based on my understanding, the intermittent slowness experienced during specific time periods may be attributed to factors such as the data source, model design, or activities at the service level.

Kindly consider the following optimisation steps, which might help in resolving the issue:

1. Use the Performance Analyzer in Power BI Desktop to identify which visuals or queries contribute most to report slowness during the affected time frames.
2. Enable Query Diagnostics in Power BI Service to pinpoint delays in report queries and ascertain whether the bottleneck lies within Power BI or the data source (Databricks).
3. For large datasets, perform pre-aggregation at the model level to reduce the overhead of real-time queries.
4. Use Incremental Refresh for large tables to reduce data load times and significantly improve query performance.
5. If your workspace is hosted in a Fabric (Premium) capacity, utilise the Metrics app to monitor query duration and capacity usage during periods of slowness.
6. Optimise the model and relationships by removing unused columns and tables. Adopt a star schema design and minimise high-cardinality columns.

If you find this response helpful, kindly mark it as the accepted solution and provide kudos. This will assist other community members facing similar issues.

Should you have any further queries, please feel free to contact the Microsoft Fabric Community.

Thank you.

[BhavinVyas3003 · Accepted solution]

The reports work fine on some days because Databricks load and cluster performance can vary daily. If fewer jobs or users are active, the cluster handles queries faster. On busy days, it slows down.

Check Databricks job and user load during slow times
Enable auto-scaling or increase cluster size
Optimise model and use query caching in Power BI
Prefer scheduled refresh over live connection if delay is frequent