Microsoft has made strides in enhancing the communication performance of XMLA-based tools. The company has introduced improvements to the XMLA endpoint in Power BI Premium and Power BI Premium Per User (PPU). XML for Analysis (XMLA) is an industry standard for data access in analytical systems, such as online analytical processing (OLAP) and data mining. The improvements aim to optimize the performance of client tools that use the XMLA protocol to communicate with Power BI datasets.
Open-Platform Connectivity with XMLA Endpoints
Power BI Premium, Premium Per User, and Power BI Embedded workspaces utilize an XMLA endpoint to facilitate open-platform connectivity. This allows both Microsoft and third-party client applications and tools to connect seamlessly. The XMLA protocol is the primary communication method between client applications and the engine that oversees Power BI workspaces and datasets. All data transmitted via the XMLA protocol is encrypted to ensure security.
Read-Only vs. Read-Write Operations
By default, the XMLA endpoint is set to read-only, enabling data visualization applications and tools to query dataset model data, metadata, events, and schema. However, users have the option to enable read-write operations. This provides enhanced dataset management, governance, advanced semantic modeling, debugging, and monitoring capabilities. When activated, datasets achieve greater parity with Azure Analysis Services and SQL Server Analysis Services enterprise-grade tabular modeling tools and processes.
Client Applications and Tools Compatibility
Several client applications and tools that were previously compatible with Azure Analysis Services and SQL Server Analysis Services are now supported by Power BI Premium datasets. Some of these tools include Microsoft Excel, Visual Studio with Analysis Services projects, SQL Server Management Studio (SSMS), SQL Server Profiler, and Power BI Report Builder, among others.
Enhancing Dataset Operations
For those using the XMLA endpoint for dataset management with write operations, Microsoft recommends enabling the dataset for large models. This action reduces the overhead of write operations, potentially speeding up the process significantly, especially for datasets larger than 1 GB after compression.
Security and Access Control
Access through the XMLA endpoint respects security group memberships set at the workspace/app level. Workspace contributors have permissions akin to Analysis Services database admins, allowing them to deploy new datasets from Visual Studio and execute TMSL scripts in SSMS. On the other hand, users with Build dataset permissions are equivalent to Analysis Services database readers. They can connect to and browse datasets for data consumption and visualization while adhering to row-level security (RLS) rules.
The XMLA endpoint supports user impersonation using the EffectiveUserName connection string property when connecting to Premium workspace datasets. This feature ensures that the specified account in EffectiveUserName is present in the tenant's Azure Active Directory and possesses both Read and Build permissions for the dataset being accessed.