Init supabase inside isolate throw error

[richard457]

loadSupabase() async {
  await Supabase.initialize(
    url: AppSecrets.superbaseurl,
    anonKey: AppSecrets.supabaseAnonKey,
  );
}

When Openning the above inside isolate throws error and when attempt to access Supabase.instance etc...

[dshukertjr]

Supabase uses isolates internally to efficiently parse JSON objects, but what is the reason why you want to initialize Supabase inside an isolate?

[richard457]

I am working on a bridge tool to migrate data from realm device sync, I am planning to use power sync and supabase to have the sync functionality and I will keep realm as cache layer on top, so I need to write a method that will keep listening change from supabse and mutate the local realm, for that reason, I can't spawn isolate and pass in Supabase. instance hence I need to init the supabase inside isolate. this code

Future<void> openDatabase() async {
  // Open the local database
  db = PowerSyncDatabase(
      schema: schema, path: await getDatabasePath(), logger: attachedLogger);
  await db.initialize();

  // await loadSupabase();
  await Supabase.initialize(
    url: AppSecrets.superbaseurl,
    anonKey: AppSecrets.supabaseAnonKey,
  );

  SupabaseConnector? currentConnector;

  if (isLoggedIn()) {
    // If the user is already logged in, connect immediately.
    // Otherwise, connect once logged in.
    print("connector");
    currentConnector = SupabaseConnector(db);
    db.connect(connector: currentConnector);
  }

  Supabase.instance.client.auth.onAuthStateChange.listen((data) async {
    final AuthChangeEvent event = data.event;
    if (event == AuthChangeEvent.signedIn) {
      // Connect to PowerSync when the user is signed in
      currentConnector = SupabaseConnector(db);
      db.connect(connector: currentConnector!);
    } else if (event == AuthChangeEvent.signedOut) {
      // Implicit sign out - disconnect, but don't delete data
      currentConnector = null;
      await db.disconnect();
    } else if (event == AuthChangeEvent.tokenRefreshed) {
      // Supabase token refreshed - trigger token refresh for PowerSync.
      currentConnector?.prefetchCredentials();
    }
  });


}

is supposed to run in isolate to avoid using more resources on root isolate.

[richard457]

cc @dshukertjr

[richard457]

I saw this #696 but I do not how it was resolved or any documentation of how to achieve the same.

[dshukertjr]

I still don't see why you would need to run the code in an isolate. I don't know about non-Supabase related code, but for all the supabase-flutter related code, don't worry about running them on an isolate and just call them from the main thread. Heavy json parsing and stuff will be handled in an isolate. If you are noticing any glitch on the UI, then it's most likely not coming from supabase-flutter, so optimize those non-Supabase related code by putting them in an isolate.

[richard457]

@dshukertjr I do not think you understand why I need to init the supabse inside isolate, first, it is not about optimization, it is about having access to the instance of supabse in isolate so closing this is not solving my use case.

[dshukertjr]

@richard457 Could you clarify why you need to initialize Supabase in an isolate?

[richard457]

For my use case, I want to use supabase to build sync layer on top of my local DB, I find it usable only if I can do this heavy process in isolation. cc @dshukertjr

[dshukertjr]

@richard457 You still shouldn't need to initialize Supabase in an isolate. You can just pass whatever you get from Supabase to the isolate to handle writing it to the local DB. Supabase itself has nothing to do with the local DB.

[richard457]

I understand that it is no go to initialize supabse in isolate and that is fine, is there a way to access data in supabase inside isolate then? @dshukertjr

[dshukertjr]

@richard457 Why don't you retrieve the data outside of the isolate and pass the data to the isolate where you do the sync to your local db?

[danyialkhan]

@dshukertjr I am facing similar issue as @richard457 but in a quite opposite way, here I am trying to upload the batches of data to the supabase in this upload function, the issue here is that it blocks the main tread. But it shouldn't as user will generate the data and app should be responsive all the time. Here is the upload function code.

  // Upload pending changes to Supabase.
  @override
  Future<void> uploadData(PowerSyncDatabase database) async {
    // This function is called whenever there is data to upload, whether the
    // device is online or offline.
    // If this call throws an error, it is retried periodically.
    final batch = await database.getCrudBatch(limit: 500);
    if (batch == null) {
      return;
    }

    final rest = Supabase.instance.client.rest;
    CrudEntry? lastOp;
    try {
      // Note: If transactional consistency is important, use database functions
      // or edge functions to process the entire batch in a single call.

      List<Future> futures = [];

      for (var op in batch.crud) {
        lastOp = op;

        final table = rest.from(op.table);
        if (op.op == UpdateType.put) {
          var data = Map<String, dynamic>.of(op.opData!);
          data['id'] = op.id;
          futures.add(table.upsert(data));
        } else if (op.op == UpdateType.patch) {
          futures.add(table.update(op.opData!).eq('id', op.id));
        } else if (op.op == UpdateType.delete) {
          futures.add(table.delete().eq('id', op.id));
        }
      }

      await Future.wait(futures);

      // All operations successful.
      await batch.complete();
    } on PostgrestException catch (e) {
      if (e.code != null && fatalResponseCodes.any((re) => re.hasMatch(e.code!))) {
        /// Instead of blocking the queue with these errors,
        /// discard the (rest of the) batch.
        ///
        /// Note that these errors typically indicate a bug in the application.
        /// If protecting against data loss is important, save the failing records
        /// elsewhere instead of discarding, and/or notify the user.s
        log.severe('Data upload error - discarding $lastOp', e);
        await batch.complete();
      } else {
        // Error may be retryable - e.g. network error or temporary server error.
        // Throwing an error here causes this call to be retried after a delay.
        rethrow;
      }
    }
  }

[Vinzent03]

@danyialkhan I'm not sure what your exact issue is. The only heavy computation beside the http connection itself (which is async) is json encoding and that's already handled by the isolate if the data is longer than 10.000 characters. So I'm unsure what else should be handled by another isolate. How do you come to the conclusion that the supabase library is causing performance issues here?