streamQuery method

Stream<ParsedRowBuffer> streamQuery(int connectionId, String sql, { int chunkSize = 1000, })

Executes a SQL query and returns results as a stream.

The connectionId must be a valid active connection. The sql should be a valid SQL SELECT statement.

The chunkSize specifies how many rows to fetch per chunk (default: 1000). Results are streamed as ParsedRowBuffer instances, allowing efficient processing of large result sets without loading everything into memory.

Example:

await for (final chunk in native.streamQuery(
  connId,
  'SELECT * FROM users',
)) {
  // Process chunk
}

Implementation

Stream<ParsedRowBuffer> streamQuery(
  int connectionId,
  String sql, {
  int chunkSize = 1000,
}) async* {
  final streamId =
      _native.streamStart(connectionId, sql, chunkSize: chunkSize);

  if (streamId == 0) {
    throw Exception('Failed to start stream: ${_native.getError()}');
  }

  final buffer = BytesBuilder(copy: false);
  try {
    while (true) {
      final result = _native.streamFetch(streamId);

      if (!result.success) {
        throw Exception('Stream fetch failed: ${_native.getError()}');
      }

      final data = result.data;
      if (data == null || data.isEmpty) {
        break;
      }
      buffer.add(data);

      if (!result.hasMore) {
        break;
      }
    }
    if (buffer.length > 0) {
      final parsed = BinaryProtocolParser.parse(buffer.toBytes());
      yield parsed;
    }
  } finally {
    _native.streamClose(streamId);
  }
}