Function ExecStatsToJsonHelper

be/src/service/impala-http-handler.cc:1143–1177

namespace {

void ExecStatsToJsonHelper(
    const TPlanNodeExecSummary& summary, rapidjson::Document* document, Value* value) {
  int64_t cardinality = 0;
  int64_t max_time = 0;
  int64_t total_time = 0;
  for (const TExecStats& stat : summary.exec_stats) {
    if (summary.is_broadcast) {
      // Avoid multiple-counting for recipients of broadcasts.
      cardinality = ::max(cardinality, stat.cardinality);
    } else {
      cardinality += stat.cardinality;
    }
    total_time += stat.latency_ns;
    max_time = ::max(max_time, stat.latency_ns);
  }
  value->AddMember("output_card", cardinality, document->GetAllocator());
  value->AddMember("num_instances", static_cast<uint64_t>(summary.exec_stats.size()),
      document->GetAllocator());
  if (summary.is_broadcast) {
    value->AddMember("is_broadcast", true, document->GetAllocator());
  }

  const string& max_time_str = PrettyPrinter::Print(max_time, TUnit::TIME_NS);
  Value max_time_str_json(max_time_str, document->GetAllocator());
  value->AddMember("max_time", max_time_str_json, document->GetAllocator());
  value->AddMember("max_time_val", max_time, document->GetAllocator());

  // Round to the nearest ns, to workaround a bug in pretty-printing a fraction of a
  // ns. See IMPALA-1800.
  const string& avg_time_str = PrettyPrinter::Print(
      // A bug may occasionally cause 1-instance nodes to appear to have 0 instances.
      total_time / ::max(static_cast<int>(summary.exec_stats.size()), 1), TUnit::TIME_NS);
  Value avg_time_str_json(avg_time_str, document->GetAllocator());
  value->AddMember("avg_time", avg_time_str_json, document->GetAllocator());
}

// Helper for PlanToJson(), processes a single list of plan nodes which are the
// DFS-flattened representation of a single plan fragment. Called recursively, the