Firebase Analytics events from iOS not showing up
I am testing the new Google-powered Firebase, and have implemented remote notifications and crash reporting. I am, however, having massive problems with getting Analytics to work.
I track events with FIRAnalytics.logEventWithName(...) and save user pproperties with FIRAnalytics.setUserPropertyString(...). However, no matter what I do, no data shows up in the Firebase Analytics Console.
Well, I do receive some events, but those are not sent by me (like first_open and session_start). Also, this data seems to drop in after a very long time.
Furthermore, when I track events and save user data, I receive the following:
Upload task scheduled to be executed in approx. (s): 3102.294599890709
This seems really strange - Firebase waiting almost an hour before trying to send the next batch of data must be a bug, or is it configurable? When I waited that extremely long delay out, data was sent...but does not show up.
Answer
Firebase events are batched together and uploaded once every hour in order to prevent excessive battery drain on the devices. On iOS when you background the app before the 1h upload target the events will be dispatched at this time in the background.
You can enable debug logging for iOS (https://firebase.google.com/docs/analytics/ios/events#view_events_in_the_xcode_debug_console) to see when events are uploaded in debug console.
Once the events are uploaded there is delay at about 3h before the data will show up in the Firebase Analytics dashboard. Also the default day range excludes "today" so you only see events from yesterday. You can switch the date picker to include Today if you like to see the latest events.
The main reason to delay/batch data uploading is to save battery. Each time the network is used the device mobile network modem is put in hi power mode and stay in this mode for a while. If network is used regularly it has sever impact on the battery life. By batching the uploads together and delaying the upload the impact on the battery is significantly reduced.