diff --git a/cpp/src/io/orc/reader_impl_chunking.cu b/cpp/src/io/orc/reader_impl_chunking.cu index 01ee5ad177d..ecf319e75ab 100644 --- a/cpp/src/io/orc/reader_impl_chunking.cu +++ b/cpp/src/io/orc/reader_impl_chunking.cu @@ -500,6 +500,8 @@ void reader_impl::load_next_stripe_data(read_mode mode) auto const [read_begin, read_end] = merge_selected_ranges(_file_itm_data.stripe_data_read_ranges, load_stripe_range); + bool stream_synchronized{false}; + for (auto read_idx = read_begin; read_idx < read_end; ++read_idx) { auto const& read_info = _file_itm_data.data_read_info[read_idx]; auto const source_ptr = _metadata.per_file_metadata[read_info.source_idx].source; @@ -507,6 +509,13 @@ void reader_impl::load_next_stripe_data(read_mode mode) lvl_stripe_data[read_info.level][read_info.stripe_idx - stripe_start].data()); if (source_ptr->is_device_read_preferred(read_info.length)) { + // `device_read_async` may not use _stream at all. + // Instead, it may use some other stream(s) to sync the H->D memcpy. + // As such, we need to make sure the device buffers in `lvl_stripe_data` are ready first. + if (!stream_synchronized) { + _stream.synchronize(); + stream_synchronized = true; + } device_read_tasks.push_back( std::pair(source_ptr->device_read_async( read_info.offset, read_info.length, dst_base + read_info.dst_pos, _stream),