Method GetNextScanRange

be/src/exec/hdfs-scan-node-base.cc:1392–1412

}

Status ScanRangeSharedState::GetNextScanRange(
    RuntimeState* state, ScanRange** scan_range) {
  DCHECK(use_mt_scan_node_) << "Should only be called by MT scan nodes";
  while (true) {
    *scan_range = scan_range_queue_.Dequeue();
    if (*scan_range != nullptr) return Status::OK();
    {
      unique_lock<mutex> l(scan_range_submission_lock_);
      while (scan_range_queue_.Empty() && remaining_scan_range_submissions_.Load() > 0
          && !state->is_cancelled()) {
        range_submission_cv_.Wait(l);
      }
    }
    // No more work to do.
    if (scan_range_queue_.Empty() && remaining_scan_range_submissions_.Load() == 0) {
      break;
    }
    if (state->is_cancelled()) return Status::CANCELLED;
  }
  return Status::OK();
}

void ScanRangeSharedState::AddCancellationHook(RuntimeState* state) {
  DCHECK(use_mt_scan_node_) << "Should only be called by MT scan nodes";