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. Hide the one-side column of relationships: The one-side column of a relationship should be hidden. But if the underlying source schema changes, the Power BI service doesn't automatically update the available fields list. For more information, see Relationships with a many-many cardinality in Power BI Desktop. That result usually prevents using any indexes, and leads to poor performance. The team usually consists of model developers and the source database administrators. Using DirectQuery means that opening or refreshing a report or dashboard always shows the latest data in the source. I see myself eventually . Design distributed tables: For Azure Synapse Analytics (formerly SQL Data Warehouse) sources, which leverage Massively Parallel Processing (MPP) architecture, consider configuring large fact-type tables as hash distributed, and dimension-type tables to replicate across all the compute nodes. Databases like SQL Server, Access, and Amazon Redshift. Each step of building a visual sends a query. Similarly, creating or editing a report requires queries to be sent for each step on the path to produce the final visual. Cross-filtering and cross-highlighting in DirectQuery require queries to be submitted to the underlying source. Click on " Storage Mode: DirectQuery (Click to change) " as shown below. When the source data lacks integrity, it's recommended that an "unknown" dimension record is added to effectively repair the data. You need to handle large data without having to pre-aggregate. For example, the Sales and Geography tables are related by two columns: CountryRegion and City. Once you provide the user credentials, Power BI uses those credentials for whoever opens the report, the same as for imported data. Using DirectQuery imposes some important limitations in some of the capabilities the Power BI service offers for published reports: Quick insights aren't supported: Power BI quick insights search different subsets of your dataset while applying a set of sophisticated algorithms to discover potentially interesting insights. For example, you can parse JSON documents, or pivot data from a column to a row form. Power BI uses the query as provided, without any attempt to rewrite it. However, it should be avoided as the calculation expression will be embedded into the source queries. You can get the actual SQL query for a set of steps by right-clicking the last step under Applied steps in Power Query Editor and choosing View Native Query. These details relate to using Power BI alone. I set up Dynamic Row Level Security for a report that uses a table from DataVerse as my security table (with email addresses). This article doesn't cover the wide range of database optimization recommendations across the full set of potential underlying sources. Immediately after you publish a DirectQuery report, you must configure the credentials of the user to use. The Power BI Desktop Performance analyzer is a useful tool for identifying issues. For some DirectQuery sources, this trace file includes all queries sent to the underlying data source. Did I answer your question ? The following limitations are common to all DirectQuery sources. DirectQuery opens a default maximum number of 10 concurrent connections. Whilst the user can select the next item prior to the query completing, it results in extra load on the underlying source. Launch PBD and navigate to File -> Options and Settings -> Preview features. Depending upon the location of the original data source, it might be necessary to configure an on-premises data gateway to get the data. That feature shares many details with Direct Query in Power BI, but there are also important differences. It may result in two queries being sent to the underlying source: It generally performs fine if there are hundreds or thousands of categories, as in this example. For example, when you use import to connect to SQL Server Analysis Services, you define a query against the external SQL Server Analysis Services source, and import the data. Thank you very much.If not, please upload some insensitive data samples and expected output. It describes DirectQuery use cases, limitations, and guidance. Managing this feature Any changes to the underlying data aren't immediately reflected in existing visuals. Click on the bottom query while holding down the Shift key; this will select all questions. The following screenshot highlights a group of events for a query. This data presents issues for solutions based on data import. The remainder of the article focuses on DirectQuery. Do not use Power Query relative date filtering: It's possible to define relative date filtering in a Power Query query. That column should be hidden, but if hidden, it doesn't appear in the field list and can't be used in visuals. Because quick insights require high-performance queries, this feature isn't available on datasets that use DirectQuery. Avoid bidirectional cross filtering on relationships. For example, rather than dragging in the CountryRegion and Sales measures, and then filtering by a particular year, apply the filter on the Year field first. For example, to display only the top five categories in the above visual. In particular, it's not possible to use a query with common table expressions, nor one that invokes stored procedures. Make a note of the location. For more information, see DirectQuery and SAP BW. Therefore, it's best to limit the number of visuals on a single page, and instead have more, simpler pages. If you use a transformation that's too complex, you get an error that either it must be deleted or the connection model switched to import. Even if there are no traces from the source, the trace file might contain useful details of how a query runs and how you can improve it. However, the first query will return all categories from the underlying source, and then the top N are determined based on the returned results. In the Power BI Desktop ribbon, click the small triangle at the bottom of the Get Data button. We understand that not all modelers have the permissions or skills to optimize a relational database. Now I added a custom column and want to see the result in the data view. 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. Importing takes advantage of the high-performance query engine of Power BI, and provides a highly interactive, fully featured experience. 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. This approach is useful when many visuals are on a single page, or many users access a report at the same time. Using a live connection is similar to DirectQuery. Opening an existing report or authoring a new report in the Power BI service queries the imported data again, ensuring interactivity. Tiles that are based on DirectQuery datasets refresh automatically by sending queries to the underlying data sources on a schedule. Double-check that the top query is selected. It's still best to hide such columns. We recommend that you educate your report consumers about your reports that are based on DirectQuery datasets. For example, a visual might show transactions in the past day. When you define the model, follow this guidance: Avoid complex queries in Power Query Editor. You can preview a representation of the actual SQL query statement for a Power Query applied step, by selecting the View Native Query option. It's not possible to switch back to DirectQuery mode, primarily because of the feature set that DirectQuery mode doesn't support. Keep measures simple: At least initially, it's recommended to limit measures to simple aggregates. Power BI connects to a large number of varied data sources, such as: You can import data from these sources into Power BI. Often, optimizations need to be applied directly to the data source to achieve good performance results. Failing to apply filters early can result in hitting the one-million row limit. For SQL Server or Azure SQL Database volatile sources, see Get started with Columnstore for real-time operational analytics. Look at the status bar on the right side. Every user sees the same data, unless row-level security is defined as part of the report. Whether the report defines row-level security. The article focuses on the DirectQuery workflow when you create a report in Power BI Desktop, but also covers connecting through DirectQuery in the Power BI service. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. Apply filters first: When first designing reports, we recommend that you apply any applicable filtersat report, page, or visual levelbefore mapping fields to the visual fields. The data changes frequently, and you need near real-time reporting. 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. Could you tell me if your problem has been solved? Power BI uses the query as provided, without an attempt to rewrite it. When you connect to SQL Server Analysis Services, you can choose to import the data or use a live connection to the selected data model. These columns are based on an expression, like Quantity multiplied by UnitPrice. Also, further actions in Power BI Desktop don't immediately appear. This section provides high-level guidance on how to successfully use DirectQuery, given its implications. If your using another connector that supports folding (e.g. When delivering reports on volatile data sources, be sure to educate report users on the use of the Refresh button. It is important to understand that DirectQuery models impose a different workload on the Power BI environment (Power BI service or Power BI Report Server) and also on the underlying data sources. Let them know to expect that refresh responses and interactive filtering may at times be slow. The table is around 20 million rows and 25 columns and it take around 15 mins to be totally loaded into Power BI The query finished executing on Snowflake in less that 2 mins and the remaining time was spent on transferring the data to Power BI We tried loading the same table from SQL Server it was ~7x faster One reason Power BI uses this pattern is so you can define a Power Query query to use a specific query statement. Each visual requires at least one query to the underlying data source. Cross-filtering two tables in a DirectQuery source by filtering them with a table outside of the source is a bad design and is not supported. When you connect to SAP BW, choosing DirectQuery allows this treatment of measures. If rows in the Sales table contain a missing product key value, substitute them with -1. Using bidirectional cross filtering can lead to query statements that don't perform well. First of all, instead of keeping the whole "500 million rows" table in DirectQuery mode, only the "hottest" data stays in the partition that will be served using DirectQuery mode. The purpose of this function is to support multi-column model relationships. The underlying source defines and applies security rules. While the CALCULATE DAX function can be used to produce sophisticated measure expressions that manipulate filter context, they can generate expensive native queries that do not perform well. Different environments (such as Power BI, Power BI Premium, or Power BI Report Server) each can impose different throughput constraints. But returning the slicer to its original value could result in it again showing the cached previous value. To avoid this, try adding the custom column in power query instead (the query editor). This folder disappears when the associated Power BI Desktop session ends. A filter that is applied from a data source to a table from another DirectQuery source can only be set on a single column. 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. Include a few more actions, to ensure that the events of interest are flushed into the trace file. DirectQuery lets a report viewer's credentials pass through to the underlying source, which applies security rules. For example, assume you have the following TPC-DS tables in SQL Server: Results in the following visual in Power BI: Refreshing that visual produces the SQL query in the following image. Select tables in DirectQuery mode After selecting tables, click on Load. You can import data to Power BI, which is the most common way to get data. For long sessions, there's a chance of early events being dropped. You can also consider adding surrogate key columns to dimension-type tables, which is a common practice in relational data warehouse designs. For example, the following graphic shows SalesAmount by Category, but only for categories with more than 20M of sales. Instead, add materialized columns in the relational database source, and consider indexing them. While DirectQuery is the simplest approach to large data, importing aggregate data might offer a solution if the underlying data source is too slow for DirectQuery. I have a similar problem. As you create or interact with a visualization, Power BI Desktop uses the imported data. Publishing the report to the Power BI service creates and uploads a dataset, the same as for import. There are, arguably, three key benefits to using DirectQuery as a source of data: Nonetheless, there are a few drawbacks to using DirectQuery. [DateCol]) AS [a0] FROM ( (SELECT * FROM table)) AS [t0] If you need the value to be in a column, then it is impossible to use MAXA () in direct query mode (at the moment) so I suggest you modify the table to use a query as source instead of a direct table reference. While it is the preferred layer to prepare the data for a DirectQuery model, some optimizations can also be achieved in the model design, without modifying the source database. Queries that take longer than four minutes fail. This button lets you make several slicer and filter selections before you apply them. Specifically, focused on manufacturing, product, or technology companies. When you create a report that uses a DirectQuery connection, follow this guidance: Consider using query reduction options: Power BI provides report options to send fewer queries, and to disable certain interactions that cause a poor experience if the resulting queries take a long time to run. No data is imported, and the underlying data source is queried to refresh visuals. You can open the trace files by using the SQL Server Profiler tool, which you can get as part of the free SQL Server Management Studio (SSMS) download. Why now? Much of the content, however, is still applicable to Power BI DirectQuery models. You can set the maximum number of connections DirectQuery opens for each underlying data source, which controls the number of queries concurrently sent to each data source. However, the limit can occur in cases where Power BI doesn't fully optimize the queries sent, and requests some intermediate result that exceeds the limit. 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. Gateway performance For information about troubleshooting gateway performance, see Troubleshoot gateways - Power BI. Power BI uses the query as provided, without an attempt to rewrite it. This article applies to DirectQuery models hosted in the Power BI service or Power BI Report Server. The ability to add custom columns in a direct query depends on the ability for the query to fold. In many cases, getting the values for such totals requires sending separate queries to the underlying source. The to column on relationships is commonly the primary key on the to table. For more information about using DirectQuery with SQL Server Analysis Services, see Use DirectQuery for Power BI datasets and Analysis Services (preview). The slicer or filter options will not be applied until the report user clicks the button. 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. When hidden, it is not available in the Fields pane and so cannot be used to configure a visual. The Assume referential integrity setting on relationships enables queries to use INNER JOIN rather than OUTER JOIN statements. DirectQuery requires no large transfer of data, because it queries data in place. 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. If you can't meet your goals by importing data, for example if the data changes frequently and reports must reflect the latest data, consider using DirectQuery. The term modeling in this context means the act of refining and enriching raw data as part of authoring a report using the data. https://www.gigxp.com/power-bi-import-vs-direct-query/, https://www.pbiusergroup.com/communities/community-home/digestviewer/viewthread?MessageKey=db1475c8-5c72-48b4-89c3-08d7b2bdaa0c&CommunityKey=b35c8468-2fd8-4e1a-8429-322c39fe7110&tab=digestviewer. Computed columns can be persisted (materialized) and, like regular columns, sometimes they can be indexed. You should start any diagnosis of performance issues in Power BI Desktop, rather than in the Power BI service or Power BI Report Server. Navigate to or enter the path to the trace file for the current Power BI session, such as
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