How do you handle background notifications to avoid database lock?

[GP4cK]

I'm trying to troubleshoot a database lock issue. One potential cause that I've identified is that when the app receives a notification while it's in the background or terminated, we call the same init() function as in our main() to fetch some more data about the notification. The init method looks like this:

  return LazyDatabase(() async {
    final dbFolder = await AppDatabase.getDatabasesPath();
    final password = await _getDatabasePassword(...);

    return NativeDatabase.createInBackground(
      dbFile,
      isolateSetup: () async {
        open.overrideFor(OperatingSystem.android, openCipherOnAndroid);
      },
      setup: (db) {
        // Check that we're actually running with SQLCipher by querying the
        // cipher_version pragma.
        final result = db.select('pragma cipher_version');
        if (result.isEmpty) throw UnsupportedError('SQLCipher unavailable');

        db
          ..execute("pragma key = '$password'")
          ..execute('pragma busy_timeout = 1000')
          // Tests that the key is correct by selecting from a table.
          ..execute('select count(*) from sqlite_master');
      },
    );
  });

We use FirebaseMessaging for notifications so the onBackgroundMessage will create a new isolate and if the user taps on the notification, I believe the main() function will be called so that will create another isolate with potentially concurrent writes to the database.
Is this correct?

What's the best way to handle this?

[simolus3]

With the busy timeout already there, I think the chance for locks shouldn't be that high.

Do you know if FCM only starts a new isolate or launches an independent Flutter engine / isolate group? If it's in the same isolate group, you could potentially use the drift_flutter package with the shareAcrossIsolates: true option set to make drift share the connection across isolates.

[GP4cK]

Thanks for your guidance. Here's the doc I found about onBackgroundMessage.
So regarding the isolate, I suppose that it depends. I guess the key thing is to make sure all the db queries are fast :).