Method Cancel

be/src/exec/buffered-plan-root-sink.cc:143–161

}

void BufferedPlanRootSink::Cancel(RuntimeState* state) {
  DCHECK(state->is_cancelled());
  // Get the lock_ to synchronize with FlushFinal(). Either FlushFinal() will be waiting
  // on the consumer_eos_ condition variable and get signalled below, or it will see
  // that is_cancelled() is true after it gets the lock. Drop the the lock before
  // signalling the CV so that a blocked thread can immediately acquire the mutex when
  // it wakes up.
  {
    unique_lock<mutex> l(lock_);
  }
  // Wake up all sleeping threads so they can check the cancellation state.
  // While it should be safe to call NotifyOne() here, prefer to use NotifyAll() to
  // ensure that all sleeping threads are awoken. The calls to NotifyAll() are not on the
  // fast path so any overhead from calling it should be negligible.
  rows_available_.NotifyAll();
  consumer_eos_.NotifyAll();
  batch_queue_has_capacity_.NotifyAll();
  discard_result(all_results_spooled_.Set(false));
}

Status BufferedPlanRootSink::GetNext(RuntimeState* state, QueryResultSet* results,
    int num_results, bool* eos, int64_t timeout_us) {