Excessive Wakeups

Wakeups are a mechanism in the AlarmManager API that lets developers set an alarm to wake up a device at a specified time. You app sets a wakeup alarm by calling one of the set() methods in AlarmManager with either the RTC_WAKEUP or ELAPSED_REALTIME_WAKEUP flag. When a wakeup alarm is triggered, the device comes out of low-power mode and holds a partial wake lock while executing the alarm's onReceive() or onAlarm() method. If wakeup alarms are triggered excessively, they can drain a device's battery.

To help you improve app quality, Android automatically monitors apps for excessive wakeup alarms and displays the information in Android Vitals. For information on how the data is collected, see Play Console docs.

If your app is waking up the device excessively, you can use the guidance in this page to diagnose and fix the problem.

Fix the problem

The AlarmManager was introduced in early versions of the Android platform, but over time, many use cases that previously required AlarmManager are now better served by newer features like JobScheduler and Firebase JobDispatcher. This section contains tips for reducing wake up alarms, but in the long term, consider migrating your app to follow the recommendations in the best practices section.

Identify the places in your app where you schedule wakeup alarms and reduce the frequency that those alarms are triggered. Here are some tips:

• Look for calls to the various set() methods in AlarmManager that include either the RTC_WAKEUP or ELAPSED_REALTIME_WAKEUP flag.

• We recommend including your package, class, or method name in your alarm's tag name so that you can easily identify the location in your source where the alarm was set. Here are some additional tips:

  • Leave out any personally identifying information (PII) in the name, such as an email address. Otherwise, the device logs _UNKNOWN instead of the alarm name.
  • Don't get the class or method name programmatically, for example by calling getName(), because it could get obfuscated by Proguard. Instead use a hard-coded string.
  • Don't add a counter or unique identifiers to alarm tags. The system will not be able to aggregate alarms that are set that way because they all have unique identifiers.

After fixing the problem, verify that your wakeup alarms are working as expected by running the following ADB command:

adb shell dumpsys alarm

This command provides information about the status of the alarm system service on the device. For more information, see dumpsys.

Best Practices

Use wakeup alarms only if your app needs to perform an user facing operation (such as posting a notification or alerting the user). For a list of AlarmManager best practices, see Scheduling Repeating Alarms.

Don't use AlarmManager to schedule background tasks, especially repeating or network background tasks. Use JobScheduler or Firebase JobDispatcher to schedule background tasks because they offer the following benefits:

• batching - jobs are combined so that battery consumption is reduced
• persistence - jobs that are marked persistent will continue to run even after the device is rebooted
• criteria - jobs can run based on conditions, such as whether or not the device is charging or WiFi is available

For more information, see Intelligent Job-Scheduling.

Don't use AlarmManager to schedule timing operations that are valid only while the app is running (in other words, the timing operation should be canceled when the user exits the app). In those situations, use the Handler class because it is easier to use and much more efficient.