[ARROW-7522] [C++][Plasma] Broken Record Batch returned from a function call

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 0.15.1
• Component/s: C++, C++ - Plasma
• Environment: macOS
• External issue URL: https://github.com/apache/arrow/issues/23786
• Assignee: Unassigned
• Reporter: Chengxin Ma
• Created: 08/Jan/20 21:54
• Updated: 11/Jan/23 07:54

Description

Scenario: retrieving Record Batch from Plasma with known Object ID.

The following code snippet works well:

int main(int argc, char **argv)
{
    plasma::ObjectID object_id = plasma::ObjectID::from_binary("0FF1CE00C0FFEE00BEEF");

    // Start up and connect a Plasma client.
    plasma::PlasmaClient client;
    ARROW_CHECK_OK(client.Connect("/tmp/store"));

    plasma::ObjectBuffer object_buffer;
    ARROW_CHECK_OK(client.Get(&object_id, 1, -1, &object_buffer));

    // Retrieve object data.
    auto buffer = object_buffer.data;

    arrow::io::BufferReader buffer_reader(buffer); 
    std::shared_ptr<arrow::ipc::RecordBatchReader> record_batch_stream_reader;
    ARROW_CHECK_OK(arrow::ipc::RecordBatchStreamReader::Open(&buffer_reader, &record_batch_stream_reader));

    std::shared_ptr<arrow::RecordBatch> record_batch;
    arrow::Status status = record_batch_stream_reader->ReadNext(&record_batch);

    std::cout << "record_batch->column_name(0): " << record_batch->column_name(0) << std::endl;
    std::cout << "record_batch->num_columns(): " << record_batch->num_columns() << std::endl;
    std::cout << "record_batch->num_rows(): " << record_batch->num_rows() << std::endl;
    std::cout << "record_batch->column(0)->length(): "
              << record_batch->column(0)->length() << std::endl;
    std::cout << "record_batch->column(0)->ToString(): "
              << record_batch->column(0)->ToString() << std::endl;
}

record_batch->column(0)->ToString() would incur a segmentation fault if retrieving Record Batch is wrapped in a function:

std::shared_ptr<arrow::RecordBatch> GetRecordBatchFromPlasma(plasma::ObjectID object_id)
{
    // Start up and connect a Plasma client.
    plasma::PlasmaClient client;
    ARROW_CHECK_OK(client.Connect("/tmp/store"));

    plasma::ObjectBuffer object_buffer;
    ARROW_CHECK_OK(client.Get(&object_id, 1, -1, &object_buffer));

    // Retrieve object data.
    auto buffer = object_buffer.data;

    arrow::io::BufferReader buffer_reader(buffer);
    std::shared_ptr<arrow::ipc::RecordBatchReader> record_batch_stream_reader;
    ARROW_CHECK_OK(arrow::ipc::RecordBatchStreamReader::Open(&buffer_reader, &record_batch_stream_reader));

    std::shared_ptr<arrow::RecordBatch> record_batch;
    arrow::Status status = record_batch_stream_reader->ReadNext(&record_batch);

    // Disconnect the client.
    ARROW_CHECK_OK(client.Disconnect());

    return record_batch;
}

int main(int argc, char **argv)
{
    plasma::ObjectID object_id = plasma::ObjectID::from_binary("0FF1CE00C0FFEE00BEEF");

    std::shared_ptr<arrow::RecordBatch> record_batch = GetRecordBatchFromPlasma(object_id);

    std::cout << "record_batch->column_name(0): " << record_batch->column_name(0) << std::endl;
    std::cout << "record_batch->num_columns(): " << record_batch->num_columns() << std::endl;
    std::cout << "record_batch->num_rows(): " << record_batch->num_rows() << std::endl;
    std::cout << "record_batch->column(0)->length(): "
              << record_batch->column(0)->length() << std::endl;
    std::cout << "record_batch->column(0)->ToString(): "
              << record_batch->column(0)->ToString() << std::endl;
}

The meta info of the Record Batch such as number of columns and rows is still available, but I can't see the content of the columns.

lldb says that the stop reason is EXC_BAD_ACCESS, so I think the Record Batch is destroyed after GetRecordBatchFromPlasma finishes. But why can I still see the meta info of this Record Batch?
What is the proper way to get the Record Batch if we insist using a function?