progress-updater.cc

Go to the documentation of this file.

// Copyright 2012 Cloudera Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "util/progress-updater.h"

#include "common/logging.h"
#include <sstream>

#include "common/names.h"

using namespace impala;

ProgressUpdater::ProgressUpdater(const string& label, int64_t total, int period) :
  label_(label), logging_level_(2), total_(total), update_period_(period),
  num_complete_(0), last_output_percentage_(0) {
}

ProgressUpdater::ProgressUpdater() :
  logging_level_(2), total_(0), update_period_(0),
  num_complete_(0), last_output_percentage_(0) {
}

void ProgressUpdater::Update(int64_t delta) {
  DCHECK_GE(delta, 0);
  if (delta == 0) return;

  num_complete_ += delta;

  // Cache some shared variables to avoid locking.  It's possible the progress
  // update is out of order (e.g. prints 1 out of 10 after 2 out of 10)
  double old_percentage = last_output_percentage_;
  int64_t num_complete = num_complete_;

  if (num_complete >= total_) {
    // Always print the final 100% complete
    VLOG(logging_level_) << label_ << " 100\% Complete ("
                         << num_complete << " out of " << total_ << ")";
    return;
  }

  // Convert to percentage as int
  int new_percentage = (static_cast<double>(num_complete) / total_) * 100;
  if (new_percentage - old_percentage > update_period_) {
    // Only update shared variable if this guy was the latest.
    __sync_val_compare_and_swap(&last_output_percentage_, old_percentage, new_percentage);
    VLOG(logging_level_) << label_ << ": " << new_percentage << "\% Complete ("
                         << num_complete << " out of " << total_ << ")";
  }
}

string ProgressUpdater::ToString() const {
  stringstream ss;
  int64_t num_complete = num_complete_;
  if (num_complete >= total_) {
    // Always print the final 100% complete
    ss << label_ << " 100\% Complete (" << num_complete << " out of " << total_ << ")";
    return ss.str();
  }
  int percentage = (static_cast<double>(num_complete) / total_) * 100;
  ss << label_ << ": " << percentage << "\% Complete ("
     << num_complete << " out of " << total_ << ")";
  return ss.str();
}