In publishing and sharing reports that have imported data, you must be careful to share only with users allowed to see the data, or you must define row-level security as part of the dataset. DirectQuery limits the data transformations you can apply within Power Query Editor. 0. Keep measures simple. That's the thing I'm not sure if I have used M expressions as I am not aware of the language. Attend online or watch the recordings of this Power BI specific conference, which includes 130+ sessions, 130+ speakers, product managers, MVPs, and experts. The performance of a DirectQuery report in the Power BI service depends on the degree of load placed on the underlying data source. Not only is it inefficient, it commonly prevents the use of indexes. In many cases, getting the values for such totals requires sending separate queries to the underlying source. For more information about DirectQuery, check out the following resources: More info about Internet Explorer and Microsoft Edge, DirectQuery in SQL Server 2016 Analysis Services, Power BI modeling guidance for Power Platform, SQL Server Index Architecture and Design Guide, Get started with Columnstore for real-time operational analytics, Guidance for designing distributed tables in Azure Synapse Analytics (formerly SQL Data Warehouse), Assume referential integrity settings in Power BI Desktop, Relationships with a many-many cardinality in Power BI Desktop, Deploying and Managing Power BI Premium Capacities, How visuals cross-filter each other in a Power BI report, DirectQuery model troubleshooting in Power BI Desktop, The first query will retrieve the categories meeting the condition (Sales > $15 million), The second query will then retrieve the necessary data for the visual, adding the categories that met the condition to the WHERE clause. 1) Sales Must be Refreshed in Near real time so "Direct Query" 2) Sales Aggregate is once per week so "Import" (performance also required) 3) Both Date and Customer has relationship with both Sales and SalesAggregate tables so "Dual" because to support performance for DirectQuery (Sales) and Import (SalesAggregate) You have a project management The setting is only enabled when there's at least one DirectQuery source in the model. When you import data, Power BI connects to the data source by using the current user's Power BI Desktop credentials, or the credentials configured for scheduled refresh from the Power BI service. The value applies to all DirectQuery sources, and to any new DirectQuery sources added to that report. There can be a large multiplier effect. This limit is intended to prevent issues caused by overly long execution times. You can find the trace file for the current session in the AppData folder for the current user, at \AppData\Local\Microsoft\Power BI Desktop\AnalysisServicesWorkspaces. You can use calculated tables when you use DirectQuery with composite models. For more information, see Aggregations in Power BI Desktop. Whether the report defines row-level security. Navigate to or enter the path to the trace file for the current Power BI session, and open FlightRecorderCurrent.trc. Depending on the cardinality of the column involved, this approach can lead to performance issues or query failures because of the one-million row limit on query results. This button lets you make several slicer and filter selections before you apply them. When a model contains tables with different storage modes, it is known as a Composite model. The following screenshot highlights a group of events for a query. These interactions can be switched off, either for the entire report (as described above for Query Reduction options), or on a case-by-case basis. This article doesn't cover the wide range of database optimization recommendations across the full set of potential underlying sources. Cross-filtering and cross-highlighting in DirectQuery require queries to be submitted to the underlying source. No support for parent-child DAX functions: When in DirectQuery mode, it's not possible to use the family of DAX PATH() functions that usually handle parent-child structures, such as charts of accounts or employee hierarchies. Create the appropriate indexes. For example, to retrieve to the sales orders that were created in the last year (relative to today's date). Aggregation tables can be added to DirectQuery tables to import a summarized representation of the table. Power BI Desktop Dynamic security cheat sheet. We understand that not all modelers have the permissions or skills to optimize a relational database. If your using another connector that supports folding (e.g. Start diagnosing performance issues in Power BI Desktop, rather than in the Power BI service. In databases where you need to do multi-column joins, Power BI doesn't allow basing relationships on multiple columns as the primary key or foreign key. If you determine that DirectQuery is the appropriate design approach, we recommend that you engage the right people on the project. Every user sees the same data, unless row-level security is defined as part of the report. Currently DirectQuery over SAP HANA treats data the same as a relational source, and produces behavior similar to import. To do so, in Power BI Desktop go to File > Options and settings > Options, and in the Preview features section, select the DirectQuery for Power BI datasets and Analysis Services checkbox to enable this preview feature. Creating a table in DirectQuery Mode The first thing is to ensure that my table is in DirectQuery mode is to follow the steps below. Using Explore in Excel results in poor performance: You can explore a dataset by using the Explore in Excel capability, which lets you create pivot tables and pivot charts in Excel. Select tables in DirectQuery mode After selecting tables, click on Load. Include a few more actions, to ensure that the events of interest flush into the trace file. Ensure data integrity is complete: It is especially important that dimension-type tables contain a column of unique values (dimension key) that maps to the fact-type table(s). I recently created this simple Power BI desktop file that allows you to try out dynamic security with the new security relationship feature as described in this blog post. Measures mean that imported data is already at a certain level of aggregation, as defined by the query. This approach initially eliminates certain components, such as the Power BI gateway. In addition to the above list of optimization techniques, each of the following reporting capabilities can contribute to performance issues: Measure filters: Visuals containing measures (or aggregates of columns) can have filters applied to those measures. Then, if the measures are sufficiently responsive, you can experiment with more complex measures, but paying attention to the performance for each. For example, if the Sales table stores data at order line level, you could create a view to summarize this data. Switch off interaction between visuals: Cross-highlighting and cross-filtering interactions require queries be submitted to the underlying source. These shaded subqueries are the exact definition of the Power Query queries. For example, selecting a different value on a slicer requires sending a new set of queries to refresh all of the affected visuals. By default, datasets refresh every hour, but you can configure refresh between weekly and every 15 minutes as part of dataset settings. DirectQuery to Power BI Datasets In the composite model, you cannot only use DirectQuery to SQL Server, Oracle, and some other DirectQuery sources, But you can also create a DirectQuery connection to a Power BI Dataset. A filter can only touch a table once. It is also possible to show an Apply button on slicers and filters. The DirectQuery table is correctly folded (check bothValue.Metadata and the native query). If the measures operate in a satisfactory manner, you can define more complex measures, but pay attention to performance. A business user can use Power BI to connect to their data in Salesforce, for example, and immediately get a dashboard, without using Power BI Desktop. When you use multiple data sources, it's important to understand the security implications of how data moves back and forth between the underlying data sources. Also, further actions in Power BI Desktop don't immediately appear. To ensure the filter is applied based on the date at the time the report runs, apply the date filter in the report. This might be supported in the future. The data remains in SQL Server. Consider also indexed views that can pre-aggregate fact table data at a higher grain. Historical data is not of particular interest, and it is just occasionally needed. Such totals should be switched off (by using the Format pane) if not necessary. Each query group has the following events: A Query Begin and Query End event, which represent the start and end of a DAX query generated by changing a visual or filter in the Power BI UI, or from filtering or transforming data in the Power Query Editor. Only the following two DirectQuery-enabled sources are available directly in the Power BI service: Even for these two sources, it's still best to start DirectQuery use within Power BI Desktop. The to column on relationships is commonly the primary key on the to table. When you use DirectQuery to connect to a data source in Power BI Desktop, the following results occur: You use Get Data to select the source. Specifically, the guidance is designed to help you determine whether DirectQuery is the appropriate mode for your model, and to improve the performance of your reports based on DirectQuery models. The view could be based on a SELECT statement that groups the Sales table data by date (at month level), customer, product, and summarizes measure values like sales, quantity, etc. Upon load, no data is imported into the Power BI store. Again, this approach commonly leads to poor performance. This use of subselect queries hasn't been shown to affect performance for the data sources DirectQuery supports. For relational sources, you can still select a set of tables that define a query that logically returns a set of data. In particular, don't use the default contains filter if you need an exact match. The earliest known humans arrived in these lands around 900,000 years ago. The combined column can be created with either a Power Query custom column, or in the model as a calculated column. In PowerBI desktop I "connected" a table with directquery. When you publish SQL Server Analysis Services reports that use live connections, the behavior in the Power BI service is similar to DirectQuery reports in the following ways: Opening an existing report or authoring a new report in the Power BI service queries the underlying SQL Server Analysis Services source, possibly requiring an on-premises data gateway. Renaming and hiding columns and measures. The only workaround is to materialize columns of an alternative type in the underlying data source. Each step of building a visual sends a query. Let them know also that it may be possible to see inconsistent results, and that a refresh of the report can resolve any inconsistencies on the report page. Power Query Editor defines the exact subselect queries. Limitations in calculated columns: Calculated columns can only be intra-row, that is they can refer only to values of other columns of the same table, without using any aggregate functions. This pattern restricts using query statements that use Common Table Expressions (CTEs) and stored procedures. The load depends on: When you open a report in the Power BI service, all the visuals on the currently visible page refresh. The following sections list general implications of using DirectQuery, and limitations related to performance, security, transformations, modeling, and reporting. When hidden, it is not available in the Fields pane and so cannot be used to configure a visual. The report pages are taking too long to load, and the tables aren't updating rapidly enough when changes are made. The query fails if there are more than a million categories. Set relationships to enforce integrity: The Assume Referential Integrity property of DirectQuery relationships determines whether Power BI will generate source queries using an inner join rather than an outer join. Median: Any aggregation, such as Sum or Count Distinct, is pushed to the underlying source.
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