streamQueryBuffer method

Stream<ParsedRowBuffer> streamQueryBuffer(int connectionId, String sql, { int chunkSize = 1000, int? maxBufferBytes, bool lazyStrings = false, })

Legacy buffer-mode streaming via odbc_stream_start. Materialises the full result in the worker before yielding a single parsed chunk.

Implementation

Stream<ParsedRowBuffer> streamQueryBuffer(
  int connectionId,
  String sql, {
  int chunkSize = 1000,
  int? maxBufferBytes,
  bool lazyStrings = false,
}) async* {
  final streamId = await _streamStart(
    connectionId,
    sql,
    chunkSize: chunkSize,
  );
  if (streamId == 0) {
    final workerError = await _safeGetWorkerError();
    throw AsyncError(
      code: AsyncErrorCode.queryFailed,
      message: workerError ?? 'Failed to start stream',
    );
  }

  final buffer = BytesBuilder(copy: false);
  final limit = maxBufferBytes;
  var completed = false;
  OdbcError? primary;
  Object? thrown;
  StackTrace? thrownStack;
  try {
    while (true) {
      final fetched = await _streamFetch(streamId);
      if (!fetched.success) {
        final workerError = fetched.error ?? await _safeGetWorkerError();
        throw AsyncError(
          code: AsyncErrorCode.queryFailed,
          message: workerError ?? 'Stream fetch failed',
        );
      }

      final data = fetched.data;
      if (data != null && data.isNotEmpty) {
        buffer.add(data);
        if (limit != null && buffer.length > limit) {
          throw const AsyncError(
            code: AsyncErrorCode.resourceExhausted,
            message: 'Streaming buffer exceeded maxBufferBytes',
          );
        }
      }

      if (!fetched.hasMore) {
        break;
      }
    }

    if (buffer.length > 0) {
      yield decodeBatchedStreamFrame(
        buffer.toBytes(),
        lazyStrings: lazyStrings,
      );
    }
    completed = true;
  } on Object catch (error, stack) {
    thrown = error;
    thrownStack = stack;
    primary = translateOdbcError(
      error,
      operation: 'streamQuery',
      stackTrace: stack,
    );
  } finally {
    final failure = await cleanupNativeResources(
      [
        if (!completed)
          (operation: 'streamCancel', action: () => streamCancel(streamId)),
        (operation: 'streamClose', action: () => _streamClose(streamId)),
      ],
      primary: primary,
    );
    if (failure != null) {
      if (identical(failure, primary) && thrown != null) {
        NativeCallContext.record(failure);
        Error.throwWithStackTrace(thrown, thrownStack!);
      }
      Error.throwWithStackTrace(
        failure,
        failure.details.stackTrace ?? StackTrace.current,
      );
    }
  }
}