Method LoadBalance

src/master/master_impl.cc:1698–1760

}

void MasterImpl::LoadBalance() {
  {
    MutexLock locker(&mutex_);
    if (!load_balance_enabled_) {
      load_balance_scheduled_ = false;
      return;
    }
  }

  LOG(INFO) << "LoadBalance start";
  int64_t start_time = get_micros();

  std::vector<TablePtr> all_table_list;
  std::vector<TabletPtr> all_tablet_list;
  tablet_manager_->ShowTable(&all_table_list, &all_tablet_list);

  std::vector<TabletNodePtr> all_node_list;
  tabletnode_manager_->GetAllTabletNodeInfo(&all_node_list);

  // Make a constant copy of tablet nodes to make sure that the returned value
  // of GetSize, GetQps, ... remain unchanged every time they are called during
  // the load balance process so as not to cause exceptions of std::sort().
  std::vector<TabletNodePtr> all_node_list_copy;
  for (size_t i = 0; i < all_node_list.size(); i++) {
    TabletNodePtr node_copy(new TabletNode(*all_node_list[i]));
    all_node_list_copy.push_back(node_copy);
  }

  uint32_t max_move_num = FLAGS_tera_master_max_move_concurrency;

  // Run qps-based-sheduler first, then size-based-scheduler
  // If read_pending occured, process it first
  max_move_num -=
      LoadBalance(load_scheduler_.get(), max_move_num, 1, all_node_list_copy, all_tablet_list);

  if (FLAGS_tera_master_load_balance_table_grained) {
    for (size_t i = 0; i < all_table_list.size(); ++i) {
      TablePtr table = all_table_list[i];
      if (table->GetStatus() != kTableEnable) {
        continue;
      }
      if (table->GetTableName() == FLAGS_tera_master_meta_table_name) {
        continue;
      }

      std::vector<TabletPtr> tablet_list;
      table->GetTablet(&tablet_list);
      max_move_num -= LoadBalance(size_scheduler_.get(), max_move_num, 3, all_node_list_copy,
                                  tablet_list, table->GetTableName());
    }
  } else {
    max_move_num -=
        LoadBalance(size_scheduler_.get(), max_move_num, 3, all_node_list_copy, all_tablet_list);
  }

  int64_t cost_time = get_micros() - start_time;
  LOG(INFO) << "LoadBalance finish, cost " << cost_time / 1000000.0 << "s";