Data Export not working on Sync-2

[esurface]

Current version: v3.17
Upgraded from:
Issue on tablet and/or server: tablets running either Android 7, 8 or 9

Exporting data from the tablet has the variable list but no information in the sql table and database.

org.test.zip

[chrisekelley]

Is this on an APK that is using the non-encrypted flag in app-config.json? We need to update the db dump code to look for that; right now it is assuming if isCordova, then dump from sqlite db.

Background from our chat:

[9:00 AM] Kelley, Chris
If the APK is running with turnOffAppLevelEncryption:true, then it is running indexedDB instead of sqlite. The app that does the db dump does not know about turnOffAppLevelEncryption:true - it only tests for isCordova - if it is running on an APK. The assumption back then is only apk's did the file-based db dumps.
​[9:01 AM] Kelley, Chris
So, it would be trying to copy over a file-based db, which would not exist in this case, or be sized 0.
​[9:02 AM] Kelley, Chris
indexedDB-based PWA's - and now APK's using turnOffAppLevelEncryption:true - would use a different method for dumping the db data.

[chrisekelley]

Check for turnOffAppLevelEncryption set to true in app-config.json

[esurface]

Confirmed - the site is using turnOffAppLevelEncryption:true

[rjcorwin]

This was fixed in v3.18.1. However, there are two problems with the backup feature. First is the backups may not be very useful because it's a list of documents as opposed to a changes feed so we can only find in the backup doc ids that don't exist in the target db as opposed to updates to documents. Second problem is if the database is large enough, it crashes the tablet when writing to disk so it needs to be batched. New ticket for v3.20.0 #2778