diff --git a/Makefile b/Makefile
index 0b113c1b5..68bc489c3 100644
--- a/Makefile
+++ b/Makefile
@@ -49,6 +49,7 @@ VALGRIND_VER := $(join $(VALGRIND_VER),valgrind)
 VALGRIND_OPTS = --error-exitcode=$(VALGRIND_ERROR) --leak-check=full
 
 TESTS = \
+	autovector_test \
 	db_test \
 	table_properties_collector_test \
 	arena_test \
@@ -226,6 +227,9 @@ signal_test: util/signal_test.o $(LIBOBJECTS)
 arena_test: util/arena_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/arena_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
 
+autovector_test: util/autovector_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) util/autovector_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 table_properties_collector_test: db/table_properties_collector_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/table_properties_collector_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
 
diff --git a/util/autovector.h b/util/autovector.h
new file mode 100644
index 000000000..2b9cb40e9
--- /dev/null
+++ b/util/autovector.h
@@ -0,0 +1,329 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+#pragma once
+
+#include <algorithm>
+#include <cassert>
+#include <exception>
+#include <iterator>
+#include <vector>
+
+namespace rocksdb {
+
+// A vector that leverages pre-allocated stack-based array to achieve better
+// performance for array with small amount of items.
+//
+// The interface resembles that of vector, but with less features since we aim
+// to solve the problem that we have in hand, rather than implementing a
+// full-fledged generic container.
+//
+// Currently we don't support:
+//  * reserve()/shrink_to_fit()/resize()
+//     If used correctly, in most cases, people should not touch the
+//     underlying vector at all.
+//  * random insert()/erase(), please only use push_back()/pop_back().
+//  * No move/swap operations. Each autovector instance has a
+//     stack-allocated array and if we want support move/swap operations, we
+//     need to copy the arrays other than just swapping the pointers. In this
+//     case we'll just explicitly forbid these operations since they may
+//     lead users to make false assumption by thinking they are inexpensive
+//     operations.
+//
+// Naming style of public methods almost follows that of the STL's.
+template <class T, size_t kSize = 8>
+class autovector {
+ public:
+  // General STL-style container member types.
+  typedef T value_type;
+  typedef typename std::vector<T>::difference_type difference_type;
+  typedef typename std::vector<T>::size_type size_type;
+  typedef value_type& reference;
+  typedef const value_type& const_reference;
+  typedef value_type* pointer;
+  typedef const value_type* const_pointer;
+
+  // This class is the base for regular/const iterator
+  template <class TAutoVector, class TValueType>
+  class iterator_impl {
+   public:
+    // -- iterator traits
+    typedef iterator_impl<TAutoVector, TValueType> self_type;
+    typedef TValueType value_type;
+    typedef TValueType& reference;
+    typedef TValueType* pointer;
+    typedef typename TAutoVector::difference_type difference_type;
+    typedef std::random_access_iterator_tag iterator_category;
+
+    iterator_impl(TAutoVector* vect, size_t index)
+      : vect_(vect)
+      , index_(index) {
+    };
+    iterator_impl(const iterator_impl&) = default;
+    ~iterator_impl() { }
+    iterator_impl& operator=(const iterator_impl&) = default;
+
+    // -- Advancement
+    // iterator++
+    self_type& operator++() {
+      ++index_;
+      return *this;
+    }
+
+    // ++iterator
+    self_type operator++(int) {
+      auto old = *this;
+      ++index_;
+      return old;
+    }
+
+    // iterator--
+    self_type& operator--() {
+      --index_;
+      return *this;
+    }
+
+    // --iterator
+    self_type operator--(int) {
+      auto old = *this;
+      --index_;
+      return old;
+    }
+
+    self_type operator-(difference_type len) {
+      return self_type(vect_, index_ - len);
+    }
+
+    difference_type operator-(const self_type& other) {
+      assert(vect_ == other.vect_);
+      return index_ - other.index_;
+    }
+
+    self_type operator+(difference_type len) {
+      return self_type(vect_, index_ + len);
+    }
+
+    self_type& operator+=(difference_type len) {
+      index_ += len;
+      return *this;
+    }
+
+    self_type& operator-=(difference_type len) {
+      index_ -= len;
+      return *this;
+    }
+
+    // -- Reference
+    reference operator*() {
+      assert(vect_->size() >= index_);
+      return (*vect_)[index_];
+    }
+    pointer operator->() {
+      assert(vect_->size() >= index_);
+      return &(*vect_)[index_];
+    }
+
+    // -- Logical Operators
+    bool operator==(const self_type& other) const {
+      assert(vect_ == other.vect_);
+      return index_ == other.index_;
+    }
+
+    bool operator!=(const self_type& other) const {
+      return !(*this == other);
+    }
+
+    bool operator>(const self_type& other) const {
+      assert(vect_ == other.vect_);
+      return index_ > other.index_;
+    }
+
+    bool operator<(const self_type& other) const {
+      assert(vect_ == other.vect_);
+      return index_ < other.index_;
+    }
+
+    bool operator>=(const self_type& other) const {
+      assert(vect_ == other.vect_);
+      return index_ >= other.index_;
+    }
+
+    bool operator<=(const self_type& other) const {
+      assert(vect_ == other.vect_);
+      return index_ <= other.index_;
+    }
+
+   private:
+    TAutoVector* vect_ = nullptr;
+    size_t index_ = 0;
+  };
+
+  typedef iterator_impl<autovector, value_type> iterator;
+  typedef iterator_impl<const autovector, const value_type> const_iterator;
+  typedef std::reverse_iterator<iterator> reverse_iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+  autovector() = default;
+  ~autovector() = default;
+
+  // -- Immutable operations
+  // Indicate if all data resides in in-stack data structure.
+  bool only_in_stack() const {
+    // If no element was inserted at all, the vector's capacity will be `0`.
+    return vect_.capacity() == 0;
+  }
+
+  size_type size() const {
+    return num_stack_items_ + vect_.size();
+  }
+
+  bool empty() const {
+    return size() == 0;
+  }
+
+  // will not check boundry
+  const_reference operator[](size_type n) const {
+    return n < kSize ? values_[n] : vect_[n - kSize];
+  }
+
+  reference operator[](size_type n) {
+    return n < kSize ? values_[n] : vect_[n - kSize];
+  }
+
+  // will check boundry
+  const_reference at(size_type n) const {
+    if (n >= size()) {
+      throw std::out_of_range("autovector: index out of range");
+    }
+    return (*this)[n];
+  }
+
+  reference at(size_type n) {
+    if (n >= size()) {
+      throw std::out_of_range("autovector: index out of range");
+    }
+    return (*this)[n];
+  }
+
+  reference front() {
+    assert(!empty());
+    return *begin();
+  }
+
+  const_reference front() const {
+    assert(!empty());
+    return *begin();
+  }
+
+  reference back() {
+    assert(!empty());
+    return *(end() - 1);
+  }
+
+  const_reference back() const {
+    assert(!empty());
+    return *(end() - 1);
+  }
+
+  // -- Mutable Operations
+  void push_back(T&& item) {
+    if (num_stack_items_ < kSize) {
+      values_[num_stack_items_++] = std::move(item);
+    } else {
+      vect_.push_back(item);
+    }
+  }
+
+  void push_back(const T& item) {
+    push_back(value_type(item));
+  }
+
+  template<class... Args>
+  void emplace_back(Args&&... args) {
+    push_back(value_type(args...));
+  }
+
+  void pop_back() {
+    assert(!empty());
+    if (!vect_.empty()) {
+      vect_.pop_back();
+    } else {
+      --num_stack_items_;
+    }
+  }
+
+  void clear() {
+    num_stack_items_ = 0;
+    vect_.clear();
+  }
+
+  // -- Copy and Assignment
+  autovector& assign(const autovector& other);
+
+  autovector(const autovector& other) {
+    assign(other);
+  }
+
+  autovector& operator=(const autovector& other) {
+    return assign(other);
+  }
+
+  // move operation are disallowed since it is very hard to make sure both
+  // autovectors are allocated from the same function stack.
+  autovector& operator=(autovector&& other) = delete;
+  autovector(autovector&& other) = delete;
+
+  // -- Iterator Operations
+  iterator begin() {
+    return iterator(this, 0);
+  }
+
+  const_iterator begin() const {
+    return const_iterator(this, 0);
+  }
+
+  iterator end() {
+    return iterator(this, this->size());
+  }
+
+  const_iterator end() const {
+    return const_iterator(this, this->size());
+  }
+
+  reverse_iterator rbegin() {
+    return reverse_iterator(end());
+  }
+
+  const_reverse_iterator rbegin() const {
+    return const_reverse_iterator(end());
+  }
+
+  reverse_iterator rend() {
+    return reverse_iterator(begin());
+  }
+
+  const_reverse_iterator rend() const {
+    return const_reverse_iterator(begin());
+  }
+
+ private:
+  size_type num_stack_items_ = 0; // current number of items
+  value_type values_[kSize]; // the first `kSize` items
+  // used only if there are more than `kSize` items.
+  std::vector<T> vect_;
+};
+
+template <class T, size_t kSize>
+autovector<T, kSize>& autovector<T, kSize>::assign(const autovector& other) {
+  // copy the internal vector
+  vect_.assign(other.vect_.begin(), other.vect_.end());
+
+  // copy array
+  num_stack_items_ = other.num_stack_items_;
+  std::copy(other.values_, other.values_ + num_stack_items_, values_);
+
+  return *this;
+}
+
+}  // rocksdb
diff --git a/util/autovector_test.cc b/util/autovector_test.cc
new file mode 100644
index 000000000..31ce4ed19
--- /dev/null
+++ b/util/autovector_test.cc
@@ -0,0 +1,286 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+
+#include <atomic>
+#include <iostream>
+
+#include "rocksdb/env.h"
+#include "util/autovector.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+namespace rocksdb {
+
+using namespace std;
+
+class AutoVectorTest { };
+
+const size_t kSize = 8;
+TEST(AutoVectorTest, PushBackAndPopBack) {
+  autovector<size_t, kSize> vec;
+  ASSERT_TRUE(vec.empty());
+  ASSERT_EQ(0ul, vec.size());
+
+  for (size_t i = 0; i < 1000 * kSize; ++i) {
+    vec.push_back(i);
+    ASSERT_TRUE(!vec.empty());
+    if (i < kSize) {
+      ASSERT_TRUE(vec.only_in_stack());
+    } else {
+      ASSERT_TRUE(!vec.only_in_stack());
+    }
+    ASSERT_EQ(i + 1, vec.size());
+    ASSERT_EQ(i, vec[i]);
+    ASSERT_EQ(i, vec.at(i));
+  }
+
+  size_t size = vec.size();
+  while (size != 0) {
+    vec.pop_back();
+    // will always be in heap
+    ASSERT_TRUE(!vec.only_in_stack());
+    ASSERT_EQ(--size, vec.size());
+  }
+
+  ASSERT_TRUE(vec.empty());
+}
+
+TEST(AutoVectorTest, EmplaceBack) {
+  typedef std::pair<int, std::string> ValueType;
+  autovector<ValueType, kSize> vec;
+
+  for (size_t i = 0; i < 1000 * kSize; ++i) {
+    vec.emplace_back(i, std::to_string(i + 123));
+    ASSERT_TRUE(!vec.empty());
+    if (i < kSize) {
+      ASSERT_TRUE(vec.only_in_stack());
+    } else {
+      ASSERT_TRUE(!vec.only_in_stack());
+    }
+
+    ASSERT_EQ(i + 1, vec.size());
+    ASSERT_EQ(i, vec[i].first);
+    ASSERT_EQ(std::to_string(i + 123), vec[i].second);
+  }
+
+  vec.clear();
+  ASSERT_TRUE(vec.empty());
+  ASSERT_TRUE(!vec.only_in_stack());
+}
+
+void AssertEqual(
+    const autovector<size_t, kSize>& a, const autovector<size_t, kSize>& b) {
+  ASSERT_EQ(a.size(), b.size());
+  ASSERT_EQ(a.empty(), b.empty());
+  ASSERT_EQ(a.only_in_stack(), b.only_in_stack());
+  for (size_t i = 0; i < a.size(); ++i) {
+    ASSERT_EQ(a[i], b[i]);
+  }
+}
+
+TEST(AutoVectorTest, CopyAndAssignment) {
+  // Test both heap-allocated and stack-allocated cases.
+  for (auto size : { kSize / 2, kSize * 1000 }) {
+    autovector<size_t, kSize> vec;
+    for (size_t i = 0; i < size; ++i) {
+      vec.push_back(i);
+    }
+
+    {
+      autovector<size_t, kSize> other;
+      other = vec;
+      AssertEqual(other, vec);
+    }
+
+    {
+      autovector<size_t, kSize> other(vec);
+      AssertEqual(other, vec);
+    }
+  }
+}
+
+TEST(AutoVectorTest, Iterators) {
+  autovector<std::string, kSize> vec;
+  for (size_t i = 0; i < kSize * 1000; ++i) {
+    vec.push_back(std::to_string(i));
+  }
+
+  // basic operator test
+  ASSERT_EQ(vec.front(), *vec.begin());
+  ASSERT_EQ(vec.back(), *(vec.end() - 1));
+  ASSERT_TRUE(vec.begin() < vec.end());
+
+  // non-const iterator
+  size_t index = 0;
+  for (const auto& item : vec) {
+    ASSERT_EQ(vec[index++], item);
+  }
+
+  index = vec.size() - 1;
+  for (auto pos = vec.rbegin(); pos != vec.rend(); ++pos) {
+    ASSERT_EQ(vec[index--], *pos);
+  }
+
+  // const iterator
+  const auto& cvec = vec;
+  index = 0;
+  for (const auto& item : cvec) {
+    ASSERT_EQ(cvec[index++], item);
+  }
+
+  index = vec.size() - 1;
+  for (auto pos = cvec.rbegin(); pos != cvec.rend(); ++pos) {
+    ASSERT_EQ(cvec[index--], *pos);
+  }
+
+  // forward and backward
+  auto pos = vec.begin();
+  while (pos != vec.end()) {
+    auto old_val = *pos;
+    auto old = pos++;
+    // HACK: make sure -> works
+    ASSERT_TRUE(!old->empty());
+    ASSERT_EQ(old_val, *old);
+    ASSERT_TRUE(old_val != *pos);
+  }
+
+  pos = vec.begin();
+  for (size_t i = 0; i < vec.size(); i += 2) {
+    // Cannot use ASSERT_EQ since that macro depends on iostream serialization
+    ASSERT_TRUE(pos + 2 - 2 == pos);
+    pos += 2;
+    ASSERT_TRUE(i + 2 == pos - vec.begin());
+    ASSERT_TRUE(pos >= vec.begin());
+    ASSERT_TRUE(pos <= vec.end());
+  }
+}
+
+vector<string> GetTestKeys(size_t size) {
+  vector<string> keys;
+  keys.resize(size);
+
+  int index = 0;
+  for (auto& key : keys) {
+    key = "item-" + to_string(index++);
+  }
+  return keys;
+}
+
+template<class TVector>
+void BenchmarkVectorCreationAndInsertion(
+    string name, size_t ops, size_t item_size,
+    const std::vector<typename TVector::value_type>& items) {
+  auto env = Env::Default();
+
+  int index = 0;
+  auto start_time = env->NowNanos();
+  auto ops_remaining = ops;
+  while(ops_remaining--) {
+    TVector v;
+    for (size_t i = 0; i < item_size; ++i) {
+      v.push_back(items[index++]);
+    }
+  }
+  auto elapsed = env->NowNanos() - start_time;
+  cout << "created " << ops << " " << name << " instances:\n\t"
+       << "each was inserted with " << item_size << " elements\n\t"
+       << "total time elapsed: " << elapsed << " (ns)" << endl;
+}
+
+template <class TVector>
+void BenchmarkSequenceAccess(string name, size_t ops, size_t elem_size) {
+  TVector v;
+  for (const auto& item : GetTestKeys(elem_size)) {
+    v.push_back(item);
+  }
+  auto env = Env::Default();
+
+  auto ops_remaining = ops;
+  auto start_time = env->NowNanos();
+  size_t total = 0;
+  while (ops_remaining--) {
+    auto end = v.end();
+    for (auto pos = v.begin(); pos != end; ++pos) {
+      total += pos->size();
+    }
+  }
+  auto elapsed = env->NowNanos() - start_time;
+  cout << "performed " << ops << " sequence access against " << name << "\n\t"
+       << "size: " << elem_size << "\n\t"
+       << "total time elapsed: " << elapsed << " (ns)" << endl;
+}
+
+// This test case only reports the performance between std::vector<string>
+// and autovector<string>. We chose string for comparison because in most
+// o our use cases we used std::vector<string>.
+TEST(AutoVectorTest, PerfBench) {
+  // We run same operations for kOps times in order to get a more fair result.
+  size_t kOps = 100000;
+
+  // Creation and insertion test
+  // Test the case when there is:
+  //  * no element inserted: internal array of std::vector may not really get
+  //    initialize.
+  //  * one element inserted: internal array of std::vector must have
+  //    initialized.
+  //  * kSize elements inserted. This shows the most time we'll spend if we
+  //    keep everything in stack.
+  //  * 2 * kSize elements inserted. The internal vector of
+  //    autovector must have been initialized.
+  cout << "=====================================================" << endl;
+  cout << "Creation and Insertion Test (value type: std::string)" << endl;
+  cout << "=====================================================" << endl;
+
+  // pre-generated unique keys
+  auto string_keys = GetTestKeys(kOps * 2 * kSize);
+  for (auto insertions : { 0ul, 1ul, kSize / 2, kSize, 2 * kSize }) {
+    BenchmarkVectorCreationAndInsertion<vector<string>>(
+      "vector<string>", kOps, insertions, string_keys
+    );
+    BenchmarkVectorCreationAndInsertion<autovector<string, kSize>>(
+      "autovector<string>", kOps, insertions, string_keys
+    );
+    cout << "-----------------------------------" << endl;
+  }
+
+  cout << "=====================================================" << endl;
+  cout << "Creation and Insertion Test (value type: uint64_t)" << endl;
+  cout << "=====================================================" << endl;
+
+  // pre-generated unique keys
+  vector<uint64_t> int_keys(kOps * 2 * kSize);
+  for (size_t i = 0; i < kOps * 2 * kSize; ++i) {
+    int_keys[i] = i;
+  }
+  for (auto insertions : { 0ul, 1ul, kSize / 2, kSize, 2 * kSize }) {
+    BenchmarkVectorCreationAndInsertion<vector<uint64_t>>(
+      "vector<uint64_t>", kOps, insertions, int_keys
+    );
+    BenchmarkVectorCreationAndInsertion<autovector<uint64_t, kSize>>(
+      "autovector<uint64_t>", kOps, insertions, int_keys
+    );
+    cout << "-----------------------------------" << endl;
+  }
+
+  // Sequence Access Test
+  cout << "=====================================================" << endl;
+  cout << "Sequence Access Test" << endl;
+  cout << "=====================================================" << endl;
+  for (auto elem_size : { kSize / 2, kSize, 2 * kSize }) {
+    BenchmarkSequenceAccess<vector<string>>(
+        "vector", kOps, elem_size
+    );
+    BenchmarkSequenceAccess<autovector<string, kSize>>(
+        "autovector", kOps, elem_size
+    );
+    cout << "-----------------------------------" << endl;
+  }
+}
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  return rocksdb::test::RunAllTests();
+}