Partial wake locks are a mechanism in the[`PowerManager`](https://developer.android.com/reference/android/os/PowerManager)API that lets developers keep the CPU running after a device's display turns off (whether due to system timeout or the user pressing the power button). Your app acquires a partial wake lock by calling[`acquire()`](https://developer.android.com/reference/android/os/PowerManager.WakeLock#acquire())with the[`PARTIAL_WAKE_LOCK`](https://developer.android.com/reference/android/os/PowerManager#PARTIAL_WAKE_LOCK)flag, or by using[other APIs that acquire wake locks](https://developer.android.com/develop/background-work/background-tasks/awake/wakelock/identify-wls). A partial wake lock becomes*stuck*if it is held for a long time while your app is running in the background (no part of your app is visible to the user). This condition drains the device's battery because it prevents the device from entering lower power states. Partial wake locks should be used only when necessary and released as soon as no longer needed.

If your app has a stuck partial wake lock, you can use the guidance in this page to diagnose and fix the problem.

## Detect the problem

You may not always know that your app's partial wake locks are stuck. If you have already published your app, Android vitals can help make you aware of the problem.

### Android vitals

Android vitals can help improve your app's performance by alerting you via the[Play Console](https://play.google.com/console/)when your app is exhibiting stuck partial wake locks. Android vitals reports partial wake locks as stuck when at least one, hour-long, while in the background, partial wake lock occurs in a 24-hour period.

The number of battery sessions displayed is an aggregate for all measured users of the app. For information on how Google Play collects Android vitals data, see the[Play Console](https://support.google.com/googleplay/android-developer/answer/7385505)documentation.

Once you're aware that your app has stuck partial wake locks, your next step is to address the issue.

## Fix the problem

Because wake locks can drain the device battery, you shouldn't use wake locks if there's an alternative. The[Choose the right API to keep the device awake](https://developer.android.com/develop/background-work/background-tasks/awake)documentation can help you find the best solution for your app.

If you do need to use a wake lock,[follow wake lock best practices](https://developer.android.com/develop/background-work/background-tasks/awake/wakelock/best-practices)to make sure your wake locks don't hurt device efficiency. In particular, make sure every device you acquire is released, and release the lock as quickly as possible.

After fixing the problem in code, you can verify your fixes by using[local wake lock debugging tools](https://developer.android.com/develop/background-work/background-tasks/awake/wakelock/debug-locally).

## See also

- [Excessive partial wake locks](https://developer.android.com/topic/performance/vitals/excessive-wakelock)
- [Wake lock documentation](https://developer.android.com/develop/background-work/background-tasks/awake/wakelock)

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- Note: link text is displayed when JavaScript is off
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- [Create and measure Baseline Profiles without Macrobenchmark](https://developer.android.com/topic/performance/baselineprofiles/manually-create-measure)