Wakelock and doze mode

Question

According to Android Marshmallow documentation when the system is in doze mode, any wakelock is ignored. However it\'s not clear to me if a wakelock prevent doze mode or not

Answer 1

In response to the comment discussion above, this is not an answer to the question. It's meant to clarify app behaviour in Doze mode in general. In my testing app, I tried to get a GPS position every 2 minutes, GPS signal strength was sufficient at all times.

Testing conditions:

• Nexus 9, Android M Preview, Build MPA44I
• "ignore optimizations" ON
• setExactAndAllowWhileIdle() with 2 minute interval
• each operation has a 1 minute timeout for getting a GPS fix and is surrounded by a partial wakelock
• logs were written to SQLiteOpenHelper.getWritableDatabase()

GPS test log for Doze mode:

1   2015-09-04 - 12:14  GPS ok (device left stationary unplugged)
2   2015-09-04 - 12:16  GPS ok
3   2015-09-04 - 12:18  GPS ok
4   2015-09-04 - 12:20  GPS ok
5   2015-09-04 - 12:22  GPS ok
6   2015-09-04 - 12:24  GPS ok
7   2015-09-04 - 12:26  GPS ok
8   2015-09-04 - 12:28  GPS ok
9   2015-09-04 - 12:30  GPS ok
10  2015-09-04 - 12:32  GPS ok
11  2015-09-04 - 12:34  GPS ok
...
31  2015-09-04 - 13:14  GPS ok
32  2015-09-04 - 13:16  GPS ok
33  2015-09-04 - 13:18  GPS ok
34  2015-09-04 - 13:20  GPS ok
35  2015-09-04 - 13:22  GPS ok
36  2015-09-04 - 13:24  GPS ok
37  2015-09-04 - 13:26  GPS ok (entering Doze mode some time after)
38  2015-09-04 - 13:42  GPS failed, active millis: 60174 (idle)
39  2015-09-04 - 13:57  GPS failed, active millis: 60128 (idle)
40  2015-09-04 - 14:12  GPS failed, active millis: 60122 (idle)
41  2015-09-04 - 14:16  GPS ok (idle maintenance)
42  2015-09-04 - 14:18  GPS ok (idle maintenance)
43  2015-09-04 - 14:20  GPS ok (idle maintenance)
44  2015-09-04 - 14:22  GPS ok (idle maintenance)
45  2015-09-04 - 14:38  GPS failed, active millis: 60143 (idle)
46  2015-09-04 - 14:53  GPS failed, active millis: 60122 (idle)
47  2015-09-04 - 15:08  GPS failed, active millis: 60068 (idle)
48  2015-09-04 - 15:23  GPS failed, active millis: 60138 (idle)
49  2015-09-04 - 15:38  GPS failed, active millis: 60140 (idle)
50  2015-09-04 - 15:53  GPS failed, active millis: 60131 (idle)
51  2015-09-04 - 16:08  GPS failed, active millis: 60185 (idle)
52  2015-09-04 - 16:12  GPS ok (ending Doze mode - power button on)

Now that I looked at my logs again, I noticed a very strange behavior: The same test with "ignore optimizations" OFF showed basically identical results (like it should), BUT most of the times the timeout did not work as expected, I got 'active millis' in the range of either ~330000 (~5 times timeout time) or even ~580000 (~10 times timeout time) while idle. This weird behavior I can not explain, but it seems to show that there actually IS some effect of the setting of "ignore optimizations" on Doze mode.

Edit: The 'strange' behavior described above is just now documented: Only with "ignore optimizations" ON, you may hold a partial wakelock in Doze idle mode.