void Run()

in db/db_bench.cc [419:534]
109 lines of code
34 McCabe index (conditional complexity)

  void Run() {
    PrintHeader();
    Open();

    const char* benchmarks = FLAGS_benchmarks;
    while (benchmarks != NULL) {
      const char* sep = strchr(benchmarks, ',');
      Slice name;
      if (sep == NULL) {
        name = benchmarks;
        benchmarks = NULL;
      } else {
        name = Slice(benchmarks, sep - benchmarks);
        benchmarks = sep + 1;
      }

      // Reset parameters that may be overridden below
      num_ = FLAGS_num;
      reads_ = (FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads);
      value_size_ = FLAGS_value_size;
      entries_per_batch_ = 1;
      write_options_ = WriteOptions();

      void (Benchmark::*method)(ThreadState*) = NULL;
      bool fresh_db = false;
      int num_threads = FLAGS_threads;

      if (name == Slice("open")) {
        method = &Benchmark::OpenBench;
        num_ /= 10000;
        if (num_ < 1) num_ = 1;
      } else if (name == Slice("fillseq")) {
        fresh_db = true;
        method = &Benchmark::WriteSeq;
      } else if (name == Slice("fillbatch")) {
        fresh_db = true;
        entries_per_batch_ = 1000;
        method = &Benchmark::WriteSeq;
      } else if (name == Slice("fillrandom")) {
        fresh_db = true;
        method = &Benchmark::WriteRandom;
      } else if (name == Slice("overwrite")) {
        fresh_db = false;
        method = &Benchmark::WriteRandom;
      } else if (name == Slice("fillsync")) {
        fresh_db = true;
        num_ /= 1000;
        write_options_.sync = true;
        method = &Benchmark::WriteRandom;
      } else if (name == Slice("fill100K")) {
        fresh_db = true;
        num_ /= 1000;
        value_size_ = 100 * 1000;
        method = &Benchmark::WriteRandom;
      } else if (name == Slice("readseq")) {
        method = &Benchmark::ReadSequential;
      } else if (name == Slice("readreverse")) {
        method = &Benchmark::ReadReverse;
      } else if (name == Slice("readrandom")) {
        method = &Benchmark::ReadRandom;
      } else if (name == Slice("readmissing")) {
        method = &Benchmark::ReadMissing;
      } else if (name == Slice("seekrandom")) {
        method = &Benchmark::SeekRandom;
      } else if (name == Slice("readhot")) {
        method = &Benchmark::ReadHot;
      } else if (name == Slice("readrandomsmall")) {
        reads_ /= 1000;
        method = &Benchmark::ReadRandom;
      } else if (name == Slice("deleteseq")) {
        method = &Benchmark::DeleteSeq;
      } else if (name == Slice("deleterandom")) {
        method = &Benchmark::DeleteRandom;
      } else if (name == Slice("readwhilewriting")) {
        num_threads++;  // Add extra thread for writing
        method = &Benchmark::ReadWhileWriting;
      } else if (name == Slice("compact")) {
        method = &Benchmark::Compact;
      } else if (name == Slice("crc32c")) {
        method = &Benchmark::Crc32c;
      } else if (name == Slice("acquireload")) {
        method = &Benchmark::AcquireLoad;
      } else if (name == Slice("snappycomp")) {
        method = &Benchmark::SnappyCompress;
      } else if (name == Slice("snappyuncomp")) {
        method = &Benchmark::SnappyUncompress;
      } else if (name == Slice("heapprofile")) {
        HeapProfile();
      } else if (name == Slice("stats")) {
        PrintStats("leveldb.stats");
      } else if (name == Slice("sstables")) {
        PrintStats("leveldb.sstables");
      } else {
        if (name != Slice()) {  // No error message for empty name
          fprintf(stderr, "unknown benchmark '%s'\n", name.ToString().c_str());
        }
      }

      if (fresh_db) {
        if (FLAGS_use_existing_db) {
          fprintf(stdout, "%-12s : skipped (--use_existing_db is true)\n",
                  name.ToString().c_str());
          method = NULL;
        } else {
          delete db_;
          db_ = NULL;
          DestroyDB(FLAGS_db, Options());
          Open();
        }
      }

      if (method != NULL) {
        RunBenchmark(num_threads, name, method);
      }
    }
  }