Does Firebase Analytics Work Offline?

Question

I know Firebase in general works offline, and syncs whenever an opportunity. Does the same thing apply to Firebase-Analytics for mobile (Android, iOS) apps?

If yes (

Answer 1

Sept 2019 source: Firebase offline: What works, what doesn't, and what you need to know (Firebase Summit 2019)

Performance Monitoring & Firebase Analytics discards data that is generally >72 hours old

Measurement tools (Perf, Analytics, Crashlytics) are suspicious of data that looks too old - Todd Kerpelman @ Firebase Summit 2019

Notably, this 72hr limit is not a hard limit like the cache size and event limits are, so there are times where more than 72hrs can be cached offline and reported back to the servers though this is not guaranteed.

Summary of Perf, Analytics, Crashlytics in above video:

• Performance Monitoring
  • Android: 10MB cache across all apps
  • iOS: 10MB cache across each app
  • oldest data is purged if limit is reached
  • discards data that is generally >72 hours old
• Analytics:
  • 100,000 events
  • most recent data gets eliminated
  • discards data that is generally >72 hours old if event limit is reached
• Crashlytics:
  • 9 crashed (up to 150K each)
  • re-writes timestamp of older data that it doesn't recognize to today as you generally want crash data

All subject to change - Todd Kerpelman @ Firebase Summit 2019

Other information:

• Data is uploaded using exponential backoff and retry methods
• Android uploads data via Google Play Services and so can send the data even when the app is not running (data is uploaded on crash) vs iOS where data is uploaded on next app start

I still cannot find a source for this information in the official Firebase documentation.