Method ReadDone

be/src/runtime/io/request-context.cc:204–230

};

void RequestContext::ReadDone(int disk_id, ReadOutcome outcome, ScanRange* range) {
  // TODO: IMPALA-4249: it is safe to touch 'range' until DecrementDiskThread() is
  // called because all clients of DiskIoMgr keep ScanRange objects alive until they
  // unregister their RequestContext.
  unique_lock<mutex> lock(lock_);
  RequestContext::PerDiskState* disk_state = &disk_states_[disk_id];
  DCHECK_GT(disk_state->num_threads_in_op(), 0);
  if (outcome == ReadOutcome::SUCCESS_EOSR) {
    // No more reads to do.
    --disk_state->num_remaining_ranges();
  } else if (outcome == ReadOutcome::SUCCESS_NO_EOSR) {
    // Schedule the next read.
    if (state_ != RequestContext::Cancelled) {
      ScheduleScanRange(lock, range);
    }
  } else if (outcome == ReadOutcome::BLOCKED_ON_BUFFER) {
    // Do nothing - the caller must add a buffer to the range or cancel it.
  } else {
    DCHECK(outcome == ReadOutcome::CANCELLED) << static_cast<int>(outcome);
    // No more reads - clean up the scan range.
    --disk_state->num_remaining_ranges();
    RemoveActiveScanRangeLocked(lock, range);
  }
  // Release refcount that was taken in IncrementDiskThreadAfterDequeue().
  disk_state->DecrementDiskThread(lock, this);
  DCHECK(Validate()) << endl << DebugString();
}

void RequestContext::OperDone(RequestRange* range, const Status& status) {
  DCHECK(range != nullptr);