• Why do I see stale data in my data page after I update it?
• Why don't I see data page errors in my form?
• Why is my data page loading more often or less often than I expect?
• How do I see what data pages are currently in use?
• How can I trace data pages?
• How do I reduce the overhead involved in creating data pages?

Why do I see stale data in my data page after I update it?

After you make changes to a data page rule, you might see stale data in your case. Once a data page loads, the system caches it. If you update the data page in the meantime, and try to access it again in the case, you see the cached version of the data page.

For more information about how to clear instances of stale data, see Removing a data page.

Why don't I see data page errors in my form?

You configured a case to require certain data and to display errors if the user does not enter the required data. You tested the case by running it without the required data, but the errors did not display.

You configure errors for a data page as page messages, which are on a separate page. By default, forms only show page messages for the page that the user is currently viewing. The form does not display the error messages because they are on a separate page, and not part of the case.

As a best practice, access the required data by using autopopulated properties. Autopopulated properties are useful for accessing data that is closely related to a case. When you reference a data page from an autopopulated property, Pega Platform considers the data part of the case even though the data is not stored directly in the case. For more information, see Data page reference and Passing parameters to data pages from autopopulated properties.

Why is my data page loading more often or less often than expected?

If your data page is loading too frequently or infrequently, check the following configurations:

• Check whether the Reload if older than field on the Load Management tab is set to the appropriate time interval. For example, if this field is set to 5 minutes, the data page reloads when the page is 5 minutes old. The timer for this field starts when the data page is first loaded.
• Make sure that the Do not reload when field on the Load Management tab is configured with the correct when rule condition.
• Check whether the Reload once per interaction check box on the Load Management tab is selected.
• Confirm whether the Clear pages after non-use check box on the Load Management tab is selected. Do not clear this check box if it is already selected.

How do I see what data pages are currently in use?

You can see which data pages are in use in your application by using the following options:

• To see which data pages make up your UI, and to understand where the data originated, use the Live Data tool. For more information, see Identifying data pages with the Live Data tool.
• To understand how the system loaded data on a screen in a particular step in a case, use the Clipboard tool. For more information, see Clipboard tool.

How can I trace data pages?

To test data page loads and debug data pages as needed, use the Tracer tool. There is an event type for data pages that shows data page loads and data page access as tracer events. For more information, see Application debugging by using the Tracer tool.

How do I reduce the overhead involved in creating data pages?

Copying all of the content on a page or page list adds overhead and degrades performance. As a best practice, only copy the fields that you need. The optimal way to copy pages and page lists into your application depends on your use case.

• If you are bringing data into Pega Platform from a REST API, use the visual data mapper in App Studio.

  For more information, see Mapping fields for data pages.

• For all other use cases, use the Set option in a data transform to map the data that you need.

  For more information, see Data Transform form - Set action.