Import LevelDB 1.5, it will be used for the transaction database.

1 files changed, 978 insertions, 0 deletions

diff --git a/src/leveldb/db/db_bench.cc b/src/leveldb/db/db_bench.cc
new file mode 100644
index 0000000000..21d3e25f31
--- /dev/null
+++ b/src/leveldb/db/db_bench.cc
@@ -0,0 +1,978 @@
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "db/db_impl.h"
+#include "db/version_set.h"
+#include "leveldb/cache.h"
+#include "leveldb/db.h"
+#include "leveldb/env.h"
+#include "leveldb/write_batch.h"
+#include "port/port.h"
+#include "util/crc32c.h"
+#include "util/histogram.h"
+#include "util/mutexlock.h"
+#include "util/random.h"
+#include "util/testutil.h"
+
+// Comma-separated list of operations to run in the specified order
+//   Actual benchmarks:
+//      fillseq       -- write N values in sequential key order in async mode
+//      fillrandom    -- write N values in random key order in async mode
+//      overwrite     -- overwrite N values in random key order in async mode
+//      fillsync      -- write N/100 values in random key order in sync mode
+//      fill100K      -- write N/1000 100K values in random order in async mode
+//      deleteseq     -- delete N keys in sequential order
+//      deleterandom  -- delete N keys in random order
+//      readseq       -- read N times sequentially
+//      readreverse   -- read N times in reverse order
+//      readrandom    -- read N times in random order
+//      readmissing   -- read N missing keys in random order
+//      readhot       -- read N times in random order from 1% section of DB
+//      seekrandom    -- N random seeks
+//      crc32c        -- repeated crc32c of 4K of data
+//      acquireload   -- load N*1000 times
+//   Meta operations:
+//      compact     -- Compact the entire DB
+//      stats       -- Print DB stats
+//      sstables    -- Print sstable info
+//      heapprofile -- Dump a heap profile (if supported by this port)
+static const char* FLAGS_benchmarks =
+    "fillseq,"
+    "fillsync,"
+    "fillrandom,"
+    "overwrite,"
+    "readrandom,"
+    "readrandom,"  // Extra run to allow previous compactions to quiesce
+    "readseq,"
+    "readreverse,"
+    "compact,"
+    "readrandom,"
+    "readseq,"
+    "readreverse,"
+    "fill100K,"
+    "crc32c,"
+    "snappycomp,"
+    "snappyuncomp,"
+    "acquireload,"
+    ;
+
+// Number of key/values to place in database
+static int FLAGS_num = 1000000;
+
+// Number of read operations to do.  If negative, do FLAGS_num reads.
+static int FLAGS_reads = -1;
+
+// Number of concurrent threads to run.
+static int FLAGS_threads = 1;
+
+// Size of each value
+static int FLAGS_value_size = 100;
+
+// Arrange to generate values that shrink to this fraction of
+// their original size after compression
+static double FLAGS_compression_ratio = 0.5;
+
+// Print histogram of operation timings
+static bool FLAGS_histogram = false;
+
+// Number of bytes to buffer in memtable before compacting
+// (initialized to default value by "main")
+static int FLAGS_write_buffer_size = 0;
+
+// Number of bytes to use as a cache of uncompressed data.
+// Negative means use default settings.
+static int FLAGS_cache_size = -1;
+
+// Maximum number of files to keep open at the same time (use default if == 0)
+static int FLAGS_open_files = 0;
+
+// Bloom filter bits per key.
+// Negative means use default settings.
+static int FLAGS_bloom_bits = -1;
+
+// If true, do not destroy the existing database.  If you set this
+// flag and also specify a benchmark that wants a fresh database, that
+// benchmark will fail.
+static bool FLAGS_use_existing_db = false;
+
+// Use the db with the following name.
+static const char* FLAGS_db = NULL;
+
+namespace leveldb {
+
+namespace {
+
+// Helper for quickly generating random data.
+class RandomGenerator {
+ private:
+  std::string data_;
+  int pos_;
+
+ public:
+  RandomGenerator() {
+    // We use a limited amount of data over and over again and ensure
+    // that it is larger than the compression window (32KB), and also
+    // large enough to serve all typical value sizes we want to write.
+    Random rnd(301);
+    std::string piece;
+    while (data_.size() < 1048576) {
+      // Add a short fragment that is as compressible as specified
+      // by FLAGS_compression_ratio.
+      test::CompressibleString(&rnd, FLAGS_compression_ratio, 100, &piece);
+      data_.append(piece);
+    }
+    pos_ = 0;
+  }
+
+  Slice Generate(int len) {
+    if (pos_ + len > data_.size()) {
+      pos_ = 0;
+      assert(len < data_.size());
+    }
+    pos_ += len;
+    return Slice(data_.data() + pos_ - len, len);
+  }
+};
+
+static Slice TrimSpace(Slice s) {
+  int start = 0;
+  while (start < s.size() && isspace(s[start])) {
+    start++;
+  }
+  int limit = s.size();
+  while (limit > start && isspace(s[limit-1])) {
+    limit--;
+  }
+  return Slice(s.data() + start, limit - start);
+}
+
+static void AppendWithSpace(std::string* str, Slice msg) {
+  if (msg.empty()) return;
+  if (!str->empty()) {
+    str->push_back(' ');
+  }
+  str->append(msg.data(), msg.size());
+}
+
+class Stats {
+ private:
+  double start_;
+  double finish_;
+  double seconds_;
+  int done_;
+  int next_report_;
+  int64_t bytes_;
+  double last_op_finish_;
+  Histogram hist_;
+  std::string message_;
+
+ public:
+  Stats() { Start(); }
+
+  void Start() {
+    next_report_ = 100;
+    last_op_finish_ = start_;
+    hist_.Clear();
+    done_ = 0;
+    bytes_ = 0;
+    seconds_ = 0;
+    start_ = Env::Default()->NowMicros();
+    finish_ = start_;
+    message_.clear();
+  }
+
+  void Merge(const Stats& other) {
+    hist_.Merge(other.hist_);
+    done_ += other.done_;
+    bytes_ += other.bytes_;
+    seconds_ += other.seconds_;
+    if (other.start_ < start_) start_ = other.start_;
+    if (other.finish_ > finish_) finish_ = other.finish_;
+
+    // Just keep the messages from one thread
+    if (message_.empty()) message_ = other.message_;
+  }
+
+  void Stop() {
+    finish_ = Env::Default()->NowMicros();
+    seconds_ = (finish_ - start_) * 1e-6;
+  }
+
+  void AddMessage(Slice msg) {
+    AppendWithSpace(&message_, msg);
+  }
+
+  void FinishedSingleOp() {
+    if (FLAGS_histogram) {
+      double now = Env::Default()->NowMicros();
+      double micros = now - last_op_finish_;
+      hist_.Add(micros);
+      if (micros > 20000) {
+        fprintf(stderr, "long op: %.1f micros%30s\r", micros, "");
+        fflush(stderr);
+      }
+      last_op_finish_ = now;
+    }
+
+    done_++;
+    if (done_ >= next_report_) {
+      if      (next_report_ < 1000)   next_report_ += 100;
+      else if (next_report_ < 5000)   next_report_ += 500;
+      else if (next_report_ < 10000)  next_report_ += 1000;
+      else if (next_report_ < 50000)  next_report_ += 5000;
+      else if (next_report_ < 100000) next_report_ += 10000;
+      else if (next_report_ < 500000) next_report_ += 50000;
+      else                            next_report_ += 100000;
+      fprintf(stderr, "... finished %d ops%30s\r", done_, "");
+      fflush(stderr);
+    }
+  }
+
+  void AddBytes(int64_t n) {
+    bytes_ += n;
+  }
+
+  void Report(const Slice& name) {
+    // Pretend at least one op was done in case we are running a benchmark
+    // that does not call FinishedSingleOp().
+    if (done_ < 1) done_ = 1;
+
+    std::string extra;
+    if (bytes_ > 0) {
+      // Rate is computed on actual elapsed time, not the sum of per-thread
+      // elapsed times.
+      double elapsed = (finish_ - start_) * 1e-6;
+      char rate[100];
+      snprintf(rate, sizeof(rate), "%6.1f MB/s",
+               (bytes_ / 1048576.0) / elapsed);
+      extra = rate;
+    }
+    AppendWithSpace(&extra, message_);
+
+    fprintf(stdout, "%-12s : %11.3f micros/op;%s%s\n",
+            name.ToString().c_str(),
+            seconds_ * 1e6 / done_,
+            (extra.empty() ? "" : " "),
+            extra.c_str());
+    if (FLAGS_histogram) {
+      fprintf(stdout, "Microseconds per op:\n%s\n", hist_.ToString().c_str());
+    }
+    fflush(stdout);
+  }
+};
+
+// State shared by all concurrent executions of the same benchmark.
+struct SharedState {
+  port::Mutex mu;
+  port::CondVar cv;
+  int total;
+
+  // Each thread goes through the following states:
+  //    (1) initializing
+  //    (2) waiting for others to be initialized
+  //    (3) running
+  //    (4) done
+
+  int num_initialized;
+  int num_done;
+  bool start;
+
+  SharedState() : cv(&mu) { }
+};
+
+// Per-thread state for concurrent executions of the same benchmark.
+struct ThreadState {
+  int tid;             // 0..n-1 when running in n threads
+  Random rand;         // Has different seeds for different threads
+  Stats stats;
+  SharedState* shared;
+
+  ThreadState(int index)
+      : tid(index),
+        rand(1000 + index) {
+  }
+};
+
+}  // namespace
+
+class Benchmark {
+ private:
+  Cache* cache_;
+  const FilterPolicy* filter_policy_;
+  DB* db_;
+  int num_;
+  int value_size_;
+  int entries_per_batch_;
+  WriteOptions write_options_;
+  int reads_;
+  int heap_counter_;
+
+  void PrintHeader() {
+    const int kKeySize = 16;
+    PrintEnvironment();
+    fprintf(stdout, "Keys:       %d bytes each\n", kKeySize);
+    fprintf(stdout, "Values:     %d bytes each (%d bytes after compression)\n",
+            FLAGS_value_size,
+            static_cast<int>(FLAGS_value_size * FLAGS_compression_ratio + 0.5));
+    fprintf(stdout, "Entries:    %d\n", num_);
+    fprintf(stdout, "RawSize:    %.1f MB (estimated)\n",
+            ((static_cast<int64_t>(kKeySize + FLAGS_value_size) * num_)
+             / 1048576.0));
+    fprintf(stdout, "FileSize:   %.1f MB (estimated)\n",
+            (((kKeySize + FLAGS_value_size * FLAGS_compression_ratio) * num_)
+             / 1048576.0));
+    PrintWarnings();
+    fprintf(stdout, "------------------------------------------------\n");
+  }
+
+  void PrintWarnings() {
+#if defined(__GNUC__) && !defined(__OPTIMIZE__)
+    fprintf(stdout,
+            "WARNING: Optimization is disabled: benchmarks unnecessarily slow\n"
+            );
+#endif
+#ifndef NDEBUG
+    fprintf(stdout,
+            "WARNING: Assertions are enabled; benchmarks unnecessarily slow\n");
+#endif
+
+    // See if snappy is working by attempting to compress a compressible string
+    const char text[] = "yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy";
+    std::string compressed;
+    if (!port::Snappy_Compress(text, sizeof(text), &compressed)) {
+      fprintf(stdout, "WARNING: Snappy compression is not enabled\n");
+    } else if (compressed.size() >= sizeof(text)) {
+      fprintf(stdout, "WARNING: Snappy compression is not effective\n");
+    }
+  }
+
+  void PrintEnvironment() {
+    fprintf(stderr, "LevelDB:    version %d.%d\n",
+            kMajorVersion, kMinorVersion);
+
+#if defined(__linux)
+    time_t now = time(NULL);
+    fprintf(stderr, "Date:       %s", ctime(&now));  // ctime() adds newline
+
+    FILE* cpuinfo = fopen("/proc/cpuinfo", "r");
+    if (cpuinfo != NULL) {
+      char line[1000];
+      int num_cpus = 0;
+      std::string cpu_type;
+      std::string cache_size;
+      while (fgets(line, sizeof(line), cpuinfo) != NULL) {
+        const char* sep = strchr(line, ':');
+        if (sep == NULL) {
+          continue;
+        }
+        Slice key = TrimSpace(Slice(line, sep - 1 - line));
+        Slice val = TrimSpace(Slice(sep + 1));
+        if (key == "model name") {
+          ++num_cpus;
+          cpu_type = val.ToString();
+        } else if (key == "cache size") {
+          cache_size = val.ToString();
+        }
+      }
+      fclose(cpuinfo);
+      fprintf(stderr, "CPU:        %d * %s\n", num_cpus, cpu_type.c_str());
+      fprintf(stderr, "CPUCache:   %s\n", cache_size.c_str());
+    }
+#endif
+  }
+
+ public:
+  Benchmark()
+  : cache_(FLAGS_cache_size >= 0 ? NewLRUCache(FLAGS_cache_size) : NULL),
+    filter_policy_(FLAGS_bloom_bits >= 0
+                   ? NewBloomFilterPolicy(FLAGS_bloom_bits)
+                   : NULL),
+    db_(NULL),
+    num_(FLAGS_num),
+    value_size_(FLAGS_value_size),
+    entries_per_batch_(1),
+    reads_(FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads),
+    heap_counter_(0) {
+    std::vector<std::string> files;
+    Env::Default()->GetChildren(FLAGS_db, &files);
+    for (int i = 0; i < files.size(); i++) {
+      if (Slice(files[i]).starts_with("heap-")) {
+        Env::Default()->DeleteFile(std::string(FLAGS_db) + "/" + files[i]);
+      }
+    }
+    if (!FLAGS_use_existing_db) {
+      DestroyDB(FLAGS_db, Options());
+    }
+  }
+
+  ~Benchmark() {
+    delete db_;
+    delete cache_;
+    delete filter_policy_;
+  }
+
+  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 overriddden bwlow
+      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("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);
+      }
+    }
+  }
+
+ private:
+  struct ThreadArg {
+    Benchmark* bm;
+    SharedState* shared;
+    ThreadState* thread;
+    void (Benchmark::*method)(ThreadState*);
+  };
+
+  static void ThreadBody(void* v) {
+    ThreadArg* arg = reinterpret_cast<ThreadArg*>(v);
+    SharedState* shared = arg->shared;
+    ThreadState* thread = arg->thread;
+    {
+      MutexLock l(&shared->mu);
+      shared->num_initialized++;
+      if (shared->num_initialized >= shared->total) {
+        shared->cv.SignalAll();
+      }
+      while (!shared->start) {
+        shared->cv.Wait();
+      }
+    }
+
+    thread->stats.Start();
+    (arg->bm->*(arg->method))(thread);
+    thread->stats.Stop();
+
+    {
+      MutexLock l(&shared->mu);
+      shared->num_done++;
+      if (shared->num_done >= shared->total) {
+        shared->cv.SignalAll();
+      }
+    }
+  }
+
+  void RunBenchmark(int n, Slice name,
+                    void (Benchmark::*method)(ThreadState*)) {
+    SharedState shared;
+    shared.total = n;
+    shared.num_initialized = 0;
+    shared.num_done = 0;
+    shared.start = false;
+
+    ThreadArg* arg = new ThreadArg[n];
+    for (int i = 0; i < n; i++) {
+      arg[i].bm = this;
+      arg[i].method = method;
+      arg[i].shared = &shared;
+      arg[i].thread = new ThreadState(i);
+      arg[i].thread->shared = &shared;
+      Env::Default()->StartThread(ThreadBody, &arg[i]);
+    }
+
+    shared.mu.Lock();
+    while (shared.num_initialized < n) {
+      shared.cv.Wait();
+    }
+
+    shared.start = true;
+    shared.cv.SignalAll();
+    while (shared.num_done < n) {
+      shared.cv.Wait();
+    }
+    shared.mu.Unlock();
+
+    for (int i = 1; i < n; i++) {
+      arg[0].thread->stats.Merge(arg[i].thread->stats);
+    }
+    arg[0].thread->stats.Report(name);
+
+    for (int i = 0; i < n; i++) {
+      delete arg[i].thread;
+    }
+    delete[] arg;
+  }
+
+  void Crc32c(ThreadState* thread) {
+    // Checksum about 500MB of data total
+    const int size = 4096;
+    const char* label = "(4K per op)";
+    std::string data(size, 'x');
+    int64_t bytes = 0;
+    uint32_t crc = 0;
+    while (bytes < 500 * 1048576) {
+      crc = crc32c::Value(data.data(), size);
+      thread->stats.FinishedSingleOp();
+      bytes += size;
+    }
+    // Print so result is not dead
+    fprintf(stderr, "... crc=0x%x\r", static_cast<unsigned int>(crc));
+
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(label);
+  }
+
+  void AcquireLoad(ThreadState* thread) {
+    int dummy;
+    port::AtomicPointer ap(&dummy);
+    int count = 0;
+    void *ptr = NULL;
+    thread->stats.AddMessage("(each op is 1000 loads)");
+    while (count < 100000) {
+      for (int i = 0; i < 1000; i++) {
+        ptr = ap.Acquire_Load();
+      }
+      count++;
+      thread->stats.FinishedSingleOp();
+    }
+    if (ptr == NULL) exit(1); // Disable unused variable warning.
+  }
+
+  void SnappyCompress(ThreadState* thread) {
+    RandomGenerator gen;
+    Slice input = gen.Generate(Options().block_size);
+    int64_t bytes = 0;
+    int64_t produced = 0;
+    bool ok = true;
+    std::string compressed;
+    while (ok && bytes < 1024 * 1048576) {  // Compress 1G
+      ok = port::Snappy_Compress(input.data(), input.size(), &compressed);
+      produced += compressed.size();
+      bytes += input.size();
+      thread->stats.FinishedSingleOp();
+    }
+
+    if (!ok) {
+      thread->stats.AddMessage("(snappy failure)");
+    } else {
+      char buf[100];
+      snprintf(buf, sizeof(buf), "(output: %.1f%%)",
+               (produced * 100.0) / bytes);
+      thread->stats.AddMessage(buf);
+      thread->stats.AddBytes(bytes);
+    }
+  }
+
+  void SnappyUncompress(ThreadState* thread) {
+    RandomGenerator gen;
+    Slice input = gen.Generate(Options().block_size);
+    std::string compressed;
+    bool ok = port::Snappy_Compress(input.data(), input.size(), &compressed);
+    int64_t bytes = 0;
+    char* uncompressed = new char[input.size()];
+    while (ok && bytes < 1024 * 1048576) {  // Compress 1G
+      ok =  port::Snappy_Uncompress(compressed.data(), compressed.size(),
+                                    uncompressed);
+      bytes += input.size();
+      thread->stats.FinishedSingleOp();
+    }
+    delete[] uncompressed;
+
+    if (!ok) {
+      thread->stats.AddMessage("(snappy failure)");
+    } else {
+      thread->stats.AddBytes(bytes);
+    }
+  }
+
+  void Open() {
+    assert(db_ == NULL);
+    Options options;
+    options.create_if_missing = !FLAGS_use_existing_db;
+    options.block_cache = cache_;
+    options.write_buffer_size = FLAGS_write_buffer_size;
+    options.filter_policy = filter_policy_;
+    Status s = DB::Open(options, FLAGS_db, &db_);
+    if (!s.ok()) {
+      fprintf(stderr, "open error: %s\n", s.ToString().c_str());
+      exit(1);
+    }
+  }
+
+  void WriteSeq(ThreadState* thread) {
+    DoWrite(thread, true);
+  }
+
+  void WriteRandom(ThreadState* thread) {
+    DoWrite(thread, false);
+  }
+
+  void DoWrite(ThreadState* thread, bool seq) {
+    if (num_ != FLAGS_num) {
+      char msg[100];
+      snprintf(msg, sizeof(msg), "(%d ops)", num_);
+      thread->stats.AddMessage(msg);
+    }
+
+    RandomGenerator gen;
+    WriteBatch batch;
+    Status s;
+    int64_t bytes = 0;
+    for (int i = 0; i < num_; i += entries_per_batch_) {
+      batch.Clear();
+      for (int j = 0; j < entries_per_batch_; j++) {
+        const int k = seq ? i+j : (thread->rand.Next() % FLAGS_num);
+        char key[100];
+        snprintf(key, sizeof(key), "%016d", k);
+        batch.Put(key, gen.Generate(value_size_));
+        bytes += value_size_ + strlen(key);
+        thread->stats.FinishedSingleOp();
+      }
+      s = db_->Write(write_options_, &batch);
+      if (!s.ok()) {
+        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+    }
+    thread->stats.AddBytes(bytes);
+  }
+
+  void ReadSequential(ThreadState* thread) {
+    Iterator* iter = db_->NewIterator(ReadOptions());
+    int i = 0;
+    int64_t bytes = 0;
+    for (iter->SeekToFirst(); i < reads_ && iter->Valid(); iter->Next()) {
+      bytes += iter->key().size() + iter->value().size();
+      thread->stats.FinishedSingleOp();
+      ++i;
+    }
+    delete iter;
+    thread->stats.AddBytes(bytes);
+  }
+
+  void ReadReverse(ThreadState* thread) {
+    Iterator* iter = db_->NewIterator(ReadOptions());
+    int i = 0;
+    int64_t bytes = 0;
+    for (iter->SeekToLast(); i < reads_ && iter->Valid(); iter->Prev()) {
+      bytes += iter->key().size() + iter->value().size();
+      thread->stats.FinishedSingleOp();
+      ++i;
+    }
+    delete iter;
+    thread->stats.AddBytes(bytes);
+  }
+
+  void ReadRandom(ThreadState* thread) {
+    ReadOptions options;
+    std::string value;
+    int found = 0;
+    for (int i = 0; i < reads_; i++) {
+      char key[100];
+      const int k = thread->rand.Next() % FLAGS_num;
+      snprintf(key, sizeof(key), "%016d", k);
+      if (db_->Get(options, key, &value).ok()) {
+        found++;
+      }
+      thread->stats.FinishedSingleOp();
+    }
+    char msg[100];
+    snprintf(msg, sizeof(msg), "(%d of %d found)", found, num_);
+    thread->stats.AddMessage(msg);
+  }
+
+  void ReadMissing(ThreadState* thread) {
+    ReadOptions options;
+    std::string value;
+    for (int i = 0; i < reads_; i++) {
+      char key[100];
+      const int k = thread->rand.Next() % FLAGS_num;
+      snprintf(key, sizeof(key), "%016d.", k);
+      db_->Get(options, key, &value);
+      thread->stats.FinishedSingleOp();
+    }
+  }
+
+  void ReadHot(ThreadState* thread) {
+    ReadOptions options;
+    std::string value;
+    const int range = (FLAGS_num + 99) / 100;
+    for (int i = 0; i < reads_; i++) {
+      char key[100];
+      const int k = thread->rand.Next() % range;
+      snprintf(key, sizeof(key), "%016d", k);
+      db_->Get(options, key, &value);
+      thread->stats.FinishedSingleOp();
+    }
+  }
+
+  void SeekRandom(ThreadState* thread) {
+    ReadOptions options;
+    std::string value;
+    int found = 0;
+    for (int i = 0; i < reads_; i++) {
+      Iterator* iter = db_->NewIterator(options);
+      char key[100];
+      const int k = thread->rand.Next() % FLAGS_num;
+      snprintf(key, sizeof(key), "%016d", k);
+      iter->Seek(key);
+      if (iter->Valid() && iter->key() == key) found++;
+      delete iter;
+      thread->stats.FinishedSingleOp();
+    }
+    char msg[100];
+    snprintf(msg, sizeof(msg), "(%d of %d found)", found, num_);
+    thread->stats.AddMessage(msg);
+  }
+
+  void DoDelete(ThreadState* thread, bool seq) {
+    RandomGenerator gen;
+    WriteBatch batch;
+    Status s;
+    for (int i = 0; i < num_; i += entries_per_batch_) {
+      batch.Clear();
+      for (int j = 0; j < entries_per_batch_; j++) {
+        const int k = seq ? i+j : (thread->rand.Next() % FLAGS_num);
+        char key[100];
+        snprintf(key, sizeof(key), "%016d", k);
+        batch.Delete(key);
+        thread->stats.FinishedSingleOp();
+      }
+      s = db_->Write(write_options_, &batch);
+      if (!s.ok()) {
+        fprintf(stderr, "del error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+    }
+  }
+
+  void DeleteSeq(ThreadState* thread) {
+    DoDelete(thread, true);
+  }
+
+  void DeleteRandom(ThreadState* thread) {
+    DoDelete(thread, false);
+  }
+
+  void ReadWhileWriting(ThreadState* thread) {
+    if (thread->tid > 0) {
+      ReadRandom(thread);
+    } else {
+      // Special thread that keeps writing until other threads are done.
+      RandomGenerator gen;
+      while (true) {
+        {
+          MutexLock l(&thread->shared->mu);
+          if (thread->shared->num_done + 1 >= thread->shared->num_initialized) {
+            // Other threads have finished
+            break;
+          }
+        }
+
+        const int k = thread->rand.Next() % FLAGS_num;
+        char key[100];
+        snprintf(key, sizeof(key), "%016d", k);
+        Status s = db_->Put(write_options_, key, gen.Generate(value_size_));
+        if (!s.ok()) {
+          fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+          exit(1);
+        }
+      }
+
+      // Do not count any of the preceding work/delay in stats.
+      thread->stats.Start();
+    }
+  }
+
+  void Compact(ThreadState* thread) {
+    db_->CompactRange(NULL, NULL);
+  }
+
+  void PrintStats(const char* key) {
+    std::string stats;
+    if (!db_->GetProperty(key, &stats)) {
+      stats = "(failed)";
+    }
+    fprintf(stdout, "\n%s\n", stats.c_str());
+  }
+
+  static void WriteToFile(void* arg, const char* buf, int n) {
+    reinterpret_cast<WritableFile*>(arg)->Append(Slice(buf, n));
+  }
+
+  void HeapProfile() {
+    char fname[100];
+    snprintf(fname, sizeof(fname), "%s/heap-%04d", FLAGS_db, ++heap_counter_);
+    WritableFile* file;
+    Status s = Env::Default()->NewWritableFile(fname, &file);
+    if (!s.ok()) {
+      fprintf(stderr, "%s\n", s.ToString().c_str());
+      return;
+    }
+    bool ok = port::GetHeapProfile(WriteToFile, file);
+    delete file;
+    if (!ok) {
+      fprintf(stderr, "heap profiling not supported\n");
+      Env::Default()->DeleteFile(fname);
+    }
+  }
+};
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  FLAGS_write_buffer_size = leveldb::Options().write_buffer_size;
+  FLAGS_open_files = leveldb::Options().max_open_files;
+  std::string default_db_path;
+
+  for (int i = 1; i < argc; i++) {
+    double d;
+    int n;
+    char junk;
+    if (leveldb::Slice(argv[i]).starts_with("--benchmarks=")) {
+      FLAGS_benchmarks = argv[i] + strlen("--benchmarks=");
+    } else if (sscanf(argv[i], "--compression_ratio=%lf%c", &d, &junk) == 1) {
+      FLAGS_compression_ratio = d;
+    } else if (sscanf(argv[i], "--histogram=%d%c", &n, &junk) == 1 &&
+               (n == 0 || n == 1)) {
+      FLAGS_histogram = n;
+    } else if (sscanf(argv[i], "--use_existing_db=%d%c", &n, &junk) == 1 &&
+               (n == 0 || n == 1)) {
+      FLAGS_use_existing_db = n;
+    } else if (sscanf(argv[i], "--num=%d%c", &n, &junk) == 1) {
+      FLAGS_num = n;
+    } else if (sscanf(argv[i], "--reads=%d%c", &n, &junk) == 1) {
+      FLAGS_reads = n;
+    } else if (sscanf(argv[i], "--threads=%d%c", &n, &junk) == 1) {
+      FLAGS_threads = n;
+    } else if (sscanf(argv[i], "--value_size=%d%c", &n, &junk) == 1) {
+      FLAGS_value_size = n;
+    } else if (sscanf(argv[i], "--write_buffer_size=%d%c", &n, &junk) == 1) {
+      FLAGS_write_buffer_size = n;
+    } else if (sscanf(argv[i], "--cache_size=%d%c", &n, &junk) == 1) {
+      FLAGS_cache_size = n;
+    } else if (sscanf(argv[i], "--bloom_bits=%d%c", &n, &junk) == 1) {
+      FLAGS_bloom_bits = n;
+    } else if (sscanf(argv[i], "--open_files=%d%c", &n, &junk) == 1) {
+      FLAGS_open_files = n;
+    } else if (strncmp(argv[i], "--db=", 5) == 0) {
+      FLAGS_db = argv[i] + 5;
+    } else {
+      fprintf(stderr, "Invalid flag '%s'\n", argv[i]);
+      exit(1);
+    }
+  }
+
+  // Choose a location for the test database if none given with --db=<path>
+  if (FLAGS_db == NULL) {
+      leveldb::Env::Default()->GetTestDirectory(&default_db_path);
+      default_db_path += "/dbbench";
+      FLAGS_db = default_db_path.c_str();
+  }
+
+  leveldb::Benchmark benchmark;
+  benchmark.Run();
+  return 0;
+}