ReadOnly Annotation

The @ReadOnly annotation allows you to perform less restrictive queries against the Lightning Platform database by increasing the limit of the number of returned rows for a request to 1,000,000. All other limits still apply. The annotation blocks the following operations within the request: DML operations, calls to System.schedule, and enqueued asynchronous Apex jobs.

The @ReadOnly annotation is available for REST and SOAP Web services and the Schedulable interface. To use the @ReadOnly annotation, the top-level request must be in the schedule execution or the Web service invocation. For example, if a Visualforce page calls a Web service that contains the @ReadOnly annotation, the request fails because Visualforce is the top-level request, not the Web service.

Visualforce pages can call controller methods with the @ReadOnly annotation, and those methods run with the same relaxed restrictions. To increase other Visualforce-specific limits, such as the size of a collection that can be used by an iteration component like <apex:pageBlockTable>, you can set the readonly attribute on the <apex:page> tag to true. For more information, see Working with Large Sets of Data in the Visualforce Developer's Guide.