Optimize canvas-app performance in Power Apps

Microsoft is working hard to improve the performance of all apps that run on the Power Apps platform. But you can follow the best practices in this topic to boost the performance of apps that you create.

When a user opens an app, it goes through these phases of execution before showing any user interface:

  1. Authenticates the user - Prompts the user, if that person has never opened the app before, to sign in with credentials for whatever connections the app needs. If the same user opens the app again, that person might be prompted again, depending on the organization’s security policies.
  2. Gets metadata - Retrieves metadata such as the version of the Power Apps platform on which the app runs and the sources from which it must retrieve data.
  3. Initializes the app - Performs any tasks specified in the OnStart property.
  4. Renders screens - Renders the first screen with controls that the app has populated with data. If the user opens other screens, the app renders them by using the same process.

Limit data connections

Don’t connect to more than 30 data sources from the same app. Apps prompt new users to sign in to each connector, so every additional connector increases the amount of time that the app needs to start. As an app runs, each connector requires CPU resources, memory, and network bandwidth when the app requests data from that source.

You can quickly measure your app’s performance by turning on Developer Tools in Microsoft Edge or Google Chrome while running the app. Your app is more likely to take longer than 15 seconds to return data if it frequently requests data from more than 30 data sources, such as Common Data Service, Azure SQL, SharePoint, and Excel on OneDrive.

Limit the number of controls

Don’t add more than 500 controls to the same app. Power Apps generates an HTML DOM to render each control. The more controls you add, the more generation time Power Apps needs.

You can, in some cases, achieve the same result and have the app start faster if you use a gallery instead of individual controls. In addition, you might want to reduce the number of control types on the same screen. Some controls (such as PDF viewer, data table, and combo box) pull in large execution scripts and take longer to render.

Optimize the OnStart function

Use the ClearCollect function to cache data locally if it doesn’t change during the user session. Also, use the Concurrent function to load data sources simultaneously.

As this reference topic demonstrates, you can use Concurrent to cut the amount of time an app needs to load data in half.

Without the Concurrent function, this formula loads each of four tables one at a time:

ClearCollect( Product, '[SalesLT].[Product]' );
ClearCollect( Customer, '[SalesLT].[Customer]' );
ClearCollect( SalesOrderDetail, '[SalesLT].[SalesOrderDetail]' );
ClearCollect( SalesOrderHeader, '[SalesLT].[SalesOrderHeader]' )

You can confirm this behavior in the Developer Tools for your browser:

Serial ClearCollect

You can enclose the same formula in the Concurrent function to reduce the overall time that the operation needs:

	ClearCollect( Product, '[SalesLT].[Product]' ),
	ClearCollect( Customer, '[SalesLT].[Customer]' ),
	ClearCollect( SalesOrderDetail, '[SalesLT].[SalesOrderDetail]' ),
	ClearCollect( SalesOrderHeader, '[SalesLT].[SalesOrderHeader]' ))

With this change, the app fetches the tables in parallel:

Parallel ClearCollect

Cache lookup data

Use the Set function to cache data from lookup tables locally to avoid repeatedly retrieving data from the source. This technique optimizes performance if the data probably won’t change during a session. As in this example, the data is retrieved from the source once and then referenced locally after that until the user closes the app.

Set(CustomerOrder, Lookup(Order, id = “123-45-6789”));
Set(CustomerName, CustomerOrder.Name);
Set(CustomerAddress, CustomerOrder.Address);
Set(CustomerEmail, CustomerOrder.Email);
Set(CustomerPhone, CustomerOrder.Phone);

Contact information doesn’t change frequently, and neither do default values and user information. So you can generally use this technique with the Defaults and User functions also.

Avoid controls dependency between screens

To improve performance, the screens of an app are loaded into memory only as they are needed. This optimization can be hampered if, for example, screen 1 is loaded and one of its formulas uses a property of a control from screen 2. Now screen 2 must be loaded to fulfill the dependency before screen 1 can be displayed. Imagine screen 2 has a dependency on screen 3, which has another dependency on screen 4, and so on. This dependency chain can cause many screens to be loaded.

For this reason avoid formula dependencies between screens. In some cases you can use a global variable or collection to share information between screens.

There is an exception. In the previous example imagine that the only way to display screen 1 is by navigating from screen 2. Then screen 2 would have already been loaded in memory when screen 1 was to be loaded. No additional work is needed to fulfill the dependency for screen 2 and therefore there's no performance impact.

Use delegation

Where possible, use functions that delegate data processing to the data source instead of retrieving data to the local device for processing. If an app must process data locally, the operation requires much more processing power, memory, and network bandwidth, especially if the data set is large.

As this list shows, different data sources support delegation from different functions:

Use delegation

For example, SharePoint lists support delegation from the Filter function but not the Search function. So you should use Filter instead of Search to find items in a gallery if the SharePoint list contains more than 500 items. For more tips, see Working with large SharePoint lists in Power Apps (blog post).

Use Delayed Load

Turn on the experimental feature for Delayed Load if your app has more than 10 screens, no rules, and many controls that are on multiple screens and that are directly bound to the data source. If you build this type of app and don’t enable this feature, app performance may suffer because the controls in all screens must be populated even on screens that aren’t open. Also, all screens of the app must be updated whenever the data source changes, such as when the user adds a record.

Working with large data sets

Use data sources and formulas that can be delegated to keep your apps performing well while users can access all the information they need, and avoid hitting the data row limit of 2000 for non-delegable queries. For data-record columns on which users can search, filter, or sort data, those indexes of columns are designed well as these docs describe for SQL Server and SharePoint.

Republish apps regularly

Republish your apps (blog post) to get performance improvements and additional features from the Power Apps platform.

Avoid repeating the same formula in multiple places

If multiple properties run the same formula (especially if it's complex), consider setting it once and then referencing the output of the first property in subsequent ones. For example, don't set the DisplayMode property of controls A, B, C, D and E to the same complex formula. Instead, set A's DisplayMode property to the complex formula, set B's DisplayMode property to the result of A's DisplayMode property, and so on for C, D, and E.

Enable DelayOutput on all Text input controls

If you have multiple formulas or rules that reference the value of a Text input control, set the DelayedOutput property of that control to true. The Text property of that control will be updated only after keystrokes entered in quick succession have ceased. The formulas or rules won't run as many times, and app performance will improve.

Avoid using Form.Updates in rules and formulas

If you reference a user-input value in a rule or a formula by using a Form.Updates variable, it iterates over all the form’s data cards and creates a record each time. To make your app more efficient, reference the value directly from the data card or the control value.

Next steps

Review the coding standards for maximizing app performance and keeping apps easier to maintain.