I started experiencing slow notifications with the SmartThing Classic app; usually 10-20 minutes late. I noticed that it was after an Android OS update. So, I did some digging and found that in the latest versions of Android 8(oreo)/9(pie) Google has really been changing the power optimization and started really using the Android Doze (https://developer.android.com/training/monitoring-device-state/doze-standby) feature (though available since Android 6).
I found some articles (https://forums.androidcentral.com/android-pie/904647-notifications-delayed-stopped.html) with people complaining about slow notifications after Oreo and Pie updates and that Doze was the problem and stated that if you disable Doze, your notifications will work correctly again (near instant). I tried this and can confirm that all my notifications (including SmartThings) are working correctly now.
Now for the PITA; the only way to disable Doze is by using ADB.
- Download ADB here: https://developer.android.com/studio/releases/platform-tools
- Turn on Android Developer Options and enable ADB debugging: https://developer.android.com/studio/debug/dev-options
- Navigate to the platform-tools folder and open a command prompt (this is where ADB is).
- Run the following commands:
- adb devices
- adb shell dumpsys deviceidle disable
"adb devices" will show your android device that is connected via USB with ADB debugging enabled.
"adb shell dumpsys deviceidle disable" will disable Doze.
Please note that the above will only disable Doze until you reboot your phone. If you want to have it disabled all the time, then you need to root your phone and set a script that runs the “adb shell dumpsys deviceidle disable” command on startup. I personally do not reboot my phone often, so I will just run the command when required. I am also hoping that google will fix the notification delays caused by Doze with updates.