rocksdb/cache/lru_cache_test.cc

//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under both the GPLv2 (found in the
//  COPYING file in the root directory) and Apache 2.0 License
//  (found in the LICENSE.Apache file in the root directory).

#include "cache/lru_cache.h"

#include <string>
#include <vector>

#include "db/db_test_util.h"
#include "file/sst_file_manager_impl.h"
#include "port/port.h"
#include "port/stack_trace.h"
#include "rocksdb/cache.h"
#include "rocksdb/io_status.h"
#include "rocksdb/sst_file_manager.h"
#include "test_util/testharness.h"
#include "util/coding.h"
#include "util/random.h"
#include "utilities/fault_injection_fs.h"

namespace ROCKSDB_NAMESPACE {

class LRUCacheTest : public testing::Test {
 public:
  LRUCacheTest() {}
  ~LRUCacheTest() override { DeleteCache(); }

  void DeleteCache() {
    if (cache_ != nullptr) {
      cache_->~LRUCacheShard();
      port::cacheline_aligned_free(cache_);
      cache_ = nullptr;
    }
  }

  void NewCache(size_t capacity, double high_pri_pool_ratio = 0.0,
                bool use_adaptive_mutex = kDefaultToAdaptiveMutex) {
    DeleteCache();
    cache_ = reinterpret_cast<LRUCacheShard*>(
        port::cacheline_aligned_alloc(sizeof(LRUCacheShard)));
    new (cache_) LRUCacheShard(
        capacity, false /*strict_capcity_limit*/, high_pri_pool_ratio,
        use_adaptive_mutex, kDontChargeCacheMetadata,
        24 /*max_upper_hash_bits*/, nullptr /*secondary_cache*/);
  }

  void Insert(const std::string& key,
              Cache::Priority priority = Cache::Priority::LOW) {
    EXPECT_OK(cache_->Insert(key, 0 /*hash*/, nullptr /*value*/, 1 /*charge*/,
                             nullptr /*deleter*/, nullptr /*handle*/,
                             priority));
  }

  void Insert(char key, Cache::Priority priority = Cache::Priority::LOW) {
    Insert(std::string(1, key), priority);
  }

  bool Lookup(const std::string& key) {
    auto handle = cache_->Lookup(key, 0 /*hash*/);
    if (handle) {
      cache_->Release(handle);
      return true;
    }
    return false;
  }

  bool Lookup(char key) { return Lookup(std::string(1, key)); }

  void Erase(const std::string& key) { cache_->Erase(key, 0 /*hash*/); }

  void ValidateLRUList(std::vector<std::string> keys,
                       size_t num_high_pri_pool_keys = 0) {
    LRUHandle* lru;
    LRUHandle* lru_low_pri;
    cache_->TEST_GetLRUList(&lru, &lru_low_pri);
    LRUHandle* iter = lru;
    bool in_high_pri_pool = false;
    size_t high_pri_pool_keys = 0;
    if (iter == lru_low_pri) {
      in_high_pri_pool = true;
    }
    for (const auto& key : keys) {
      iter = iter->next;
      ASSERT_NE(lru, iter);
      ASSERT_EQ(key, iter->key().ToString());
      ASSERT_EQ(in_high_pri_pool, iter->InHighPriPool());
      if (in_high_pri_pool) {
        high_pri_pool_keys++;
      }
      if (iter == lru_low_pri) {
        ASSERT_FALSE(in_high_pri_pool);
        in_high_pri_pool = true;
      }
    }
    ASSERT_EQ(lru, iter->next);
    ASSERT_TRUE(in_high_pri_pool);
    ASSERT_EQ(num_high_pri_pool_keys, high_pri_pool_keys);
  }

 private:
  LRUCacheShard* cache_ = nullptr;
};

TEST_F(LRUCacheTest, BasicLRU) {
  NewCache(5);
  for (char ch = 'a'; ch <= 'e'; ch++) {
    Insert(ch);
  }
  ValidateLRUList({"a", "b", "c", "d", "e"});
  for (char ch = 'x'; ch <= 'z'; ch++) {
    Insert(ch);
  }
  ValidateLRUList({"d", "e", "x", "y", "z"});
  ASSERT_FALSE(Lookup("b"));
  ValidateLRUList({"d", "e", "x", "y", "z"});
  ASSERT_TRUE(Lookup("e"));
  ValidateLRUList({"d", "x", "y", "z", "e"});
  ASSERT_TRUE(Lookup("z"));
  ValidateLRUList({"d", "x", "y", "e", "z"});
  Erase("x");
  ValidateLRUList({"d", "y", "e", "z"});
  ASSERT_TRUE(Lookup("d"));
  ValidateLRUList({"y", "e", "z", "d"});
  Insert("u");
  ValidateLRUList({"y", "e", "z", "d", "u"});
  Insert("v");
  ValidateLRUList({"e", "z", "d", "u", "v"});
}

TEST_F(LRUCacheTest, MidpointInsertion) {
  // Allocate 2 cache entries to high-pri pool.
  NewCache(5, 0.45);

  Insert("a", Cache::Priority::LOW);
  Insert("b", Cache::Priority::LOW);
  Insert("c", Cache::Priority::LOW);
  Insert("x", Cache::Priority::HIGH);
  Insert("y", Cache::Priority::HIGH);
  ValidateLRUList({"a", "b", "c", "x", "y"}, 2);

  // Low-pri entries inserted to the tail of low-pri list (the midpoint).
  // After lookup, it will move to the tail of the full list.
  Insert("d", Cache::Priority::LOW);
  ValidateLRUList({"b", "c", "d", "x", "y"}, 2);
  ASSERT_TRUE(Lookup("d"));
  ValidateLRUList({"b", "c", "x", "y", "d"}, 2);

  // High-pri entries will be inserted to the tail of full list.
  Insert("z", Cache::Priority::HIGH);
  ValidateLRUList({"c", "x", "y", "d", "z"}, 2);
}

TEST_F(LRUCacheTest, EntriesWithPriority) {
  // Allocate 2 cache entries to high-pri pool.
  NewCache(5, 0.45);

  Insert("a", Cache::Priority::LOW);
  Insert("b", Cache::Priority::LOW);
  Insert("c", Cache::Priority::LOW);
  ValidateLRUList({"a", "b", "c"}, 0);

  // Low-pri entries can take high-pri pool capacity if available
  Insert("u", Cache::Priority::LOW);
  Insert("v", Cache::Priority::LOW);
  ValidateLRUList({"a", "b", "c", "u", "v"}, 0);

  Insert("X", Cache::Priority::HIGH);
  Insert("Y", Cache::Priority::HIGH);
  ValidateLRUList({"c", "u", "v", "X", "Y"}, 2);

  // High-pri entries can overflow to low-pri pool.
  Insert("Z", Cache::Priority::HIGH);
  ValidateLRUList({"u", "v", "X", "Y", "Z"}, 2);

  // Low-pri entries will be inserted to head of low-pri pool.
  Insert("a", Cache::Priority::LOW);
  ValidateLRUList({"v", "X", "a", "Y", "Z"}, 2);

  // Low-pri entries will be inserted to head of high-pri pool after lookup.
  ASSERT_TRUE(Lookup("v"));
  ValidateLRUList({"X", "a", "Y", "Z", "v"}, 2);

  // High-pri entries will be inserted to the head of the list after lookup.
  ASSERT_TRUE(Lookup("X"));
  ValidateLRUList({"a", "Y", "Z", "v", "X"}, 2);
  ASSERT_TRUE(Lookup("Z"));
  ValidateLRUList({"a", "Y", "v", "X", "Z"}, 2);

  Erase("Y");
  ValidateLRUList({"a", "v", "X", "Z"}, 2);
  Erase("X");
  ValidateLRUList({"a", "v", "Z"}, 1);
  Insert("d", Cache::Priority::LOW);
  Insert("e", Cache::Priority::LOW);
  ValidateLRUList({"a", "v", "d", "e", "Z"}, 1);
  Insert("f", Cache::Priority::LOW);
  Insert("g", Cache::Priority::LOW);
  ValidateLRUList({"d", "e", "f", "g", "Z"}, 1);
  ASSERT_TRUE(Lookup("d"));
  ValidateLRUList({"e", "f", "g", "Z", "d"}, 2);
}

class TestSecondaryCache : public SecondaryCache {
 public:
  // Specifies what action to take on a lookup for a particular key
  enum ResultType {
    SUCCESS,
    // Fail lookup immediately
    FAIL,
    // Defer the result. It will returned after Wait/WaitAll is called
    DEFER,
    // Defer the result and eventually return failure
    DEFER_AND_FAIL
  };

  using ResultMap = std::unordered_map<std::string, ResultType>;

  explicit TestSecondaryCache(size_t capacity)
      : num_inserts_(0), num_lookups_(0), inject_failure_(false) {
    cache_ = NewLRUCache(capacity, 0, false, 0.5, nullptr,
                         kDefaultToAdaptiveMutex, kDontChargeCacheMetadata);
  }
  ~TestSecondaryCache() override { cache_.reset(); }

  const char* Name() const override { return "TestSecondaryCache"; }

  void InjectFailure() { inject_failure_ = true; }

  void ResetInjectFailure() { inject_failure_ = false; }

  void SetDbSessionId(const std::string& db_session_id) {
    db_session_id_ = db_session_id;
  }

  Status Insert(const Slice& key, void* value,
                const Cache::CacheItemHelper* helper) override {
    if (inject_failure_) {
      return Status::Corruption("Insertion Data Corrupted");
    }
    assert(IsDbSessionIdAsKeyPrefix(key) == true);
    size_t size;
    char* buf;
    Status s;

    num_inserts_++;
    size = (*helper->size_cb)(value);
    buf = new char[size + sizeof(uint64_t)];
    EncodeFixed64(buf, size);
    s = (*helper->saveto_cb)(value, 0, size, buf + sizeof(uint64_t));
    if (!s.ok()) {
      delete[] buf;
      return s;
    }
    return cache_->Insert(key, buf, size,
                          [](const Slice& /*key*/, void* val) -> void {
                            delete[] static_cast<char*>(val);
                          });
  }

  std::unique_ptr<SecondaryCacheResultHandle> Lookup(
      const Slice& key, const Cache::CreateCallback& create_cb,
      bool /*wait*/) override {
    std::string key_str = key.ToString();
    TEST_SYNC_POINT_CALLBACK("TestSecondaryCache::Lookup", &key_str);

    std::unique_ptr<SecondaryCacheResultHandle> secondary_handle;
    ResultType type = ResultType::SUCCESS;
    auto iter = result_map_.find(key.ToString());
    if (iter != result_map_.end()) {
      type = iter->second;
    }
    if (type == ResultType::FAIL) {
      return secondary_handle;
    }

    Cache::Handle* handle = cache_->Lookup(key);
    num_lookups_++;
    if (handle) {
      void* value = nullptr;
      size_t charge = 0;
      Status s;
      if (type != ResultType::DEFER_AND_FAIL) {
        char* ptr = (char*)cache_->Value(handle);
        size_t size = DecodeFixed64(ptr);
        ptr += sizeof(uint64_t);
        s = create_cb(ptr, size, &value, &charge);
      }
      if (s.ok()) {
        secondary_handle.reset(new TestSecondaryCacheResultHandle(
            cache_.get(), handle, value, charge, type));
      } else {
        cache_->Release(handle);
      }
    }
    return secondary_handle;
  }

  void Erase(const Slice& /*key*/) override {}

  void WaitAll(std::vector<SecondaryCacheResultHandle*> handles) override {
    for (SecondaryCacheResultHandle* handle : handles) {
      TestSecondaryCacheResultHandle* sec_handle =
          static_cast<TestSecondaryCacheResultHandle*>(handle);
      sec_handle->SetReady();
    }
  }

  std::string GetPrintableOptions() const override { return ""; }

  void SetResultMap(ResultMap&& map) { result_map_ = std::move(map); }

  uint32_t num_inserts() { return num_inserts_; }

  uint32_t num_lookups() { return num_lookups_; }

  bool IsDbSessionIdAsKeyPrefix(const Slice& key) {
    if (db_session_id_.size() == 0) {
      return true;
    }
    if (key.size() < 20) {
      return false;
    }
    std::string s_key = key.ToString();
    if (s_key.substr(0, 20) != db_session_id_) {
      return false;
    }
    return true;
  }

 private:
  class TestSecondaryCacheResultHandle : public SecondaryCacheResultHandle {
   public:
    TestSecondaryCacheResultHandle(Cache* cache, Cache::Handle* handle,
                                   void* value, size_t size, ResultType type)
        : cache_(cache),
          handle_(handle),
          value_(value),
          size_(size),
          is_ready_(true) {
      if (type != ResultType::SUCCESS) {
        is_ready_ = false;
      }
    }

    ~TestSecondaryCacheResultHandle() override { cache_->Release(handle_); }

    bool IsReady() override { return is_ready_; }

    void Wait() override {}

    void* Value() override {
      assert(is_ready_);
      return value_;
    }

    size_t Size() override { return Value() ? size_ : 0; }

    void SetReady() { is_ready_ = true; }

   private:
    Cache* cache_;
    Cache::Handle* handle_;
    void* value_;
    size_t size_;
    bool is_ready_;
  };

  std::shared_ptr<Cache> cache_;
  uint32_t num_inserts_;
  uint32_t num_lookups_;
  bool inject_failure_;
  std::string db_session_id_;
  ResultMap result_map_;
};

class DBSecondaryCacheTest : public DBTestBase {
 public:
  DBSecondaryCacheTest()
      : DBTestBase("db_secondary_cache_test", /*env_do_fsync=*/true) {
    fault_fs_.reset(new FaultInjectionTestFS(env_->GetFileSystem()));
    fault_env_.reset(new CompositeEnvWrapper(env_, fault_fs_));
  }

  std::shared_ptr<FaultInjectionTestFS> fault_fs_;
  std::unique_ptr<Env> fault_env_;
};

class LRUSecondaryCacheTest : public LRUCacheTest {
 public:
  LRUSecondaryCacheTest() : fail_create_(false) {}
  ~LRUSecondaryCacheTest() {}

 protected:
  class TestItem {
   public:
    TestItem(const char* buf, size_t size) : buf_(new char[size]), size_(size) {
      memcpy(buf_.get(), buf, size);
    }
    ~TestItem() {}

    char* Buf() { return buf_.get(); }
    size_t Size() { return size_; }
    std::string ToString() { return std::string(Buf(), Size()); }

   private:
    std::unique_ptr<char[]> buf_;
    size_t size_;
  };

  static size_t SizeCallback(void* obj) {
    return reinterpret_cast<TestItem*>(obj)->Size();
  }

  static Status SaveToCallback(void* from_obj, size_t from_offset,
                               size_t length, void* out) {
    TestItem* item = reinterpret_cast<TestItem*>(from_obj);
    char* buf = item->Buf();
    EXPECT_EQ(length, item->Size());
    EXPECT_EQ(from_offset, 0);
    memcpy(out, buf, length);
    return Status::OK();
  }

  static void DeletionCallback(const Slice& /*key*/, void* obj) {
    delete reinterpret_cast<TestItem*>(obj);
  }

  static Cache::CacheItemHelper helper_;

  static Status SaveToCallbackFail(void* /*obj*/, size_t /*offset*/,
                                   size_t /*size*/, void* /*out*/) {
    return Status::NotSupported();
  }

  static Cache::CacheItemHelper helper_fail_;

  Cache::CreateCallback test_item_creator =
      [&](void* buf, size_t size, void** out_obj, size_t* charge) -> Status {
    if (fail_create_) {
      return Status::NotSupported();
    }
    *out_obj = reinterpret_cast<void*>(new TestItem((char*)buf, size));
    *charge = size;
    return Status::OK();
  };

  void SetFailCreate(bool fail) { fail_create_ = fail; }

 private:
  bool fail_create_;
};

Cache::CacheItemHelper LRUSecondaryCacheTest::helper_(
    LRUSecondaryCacheTest::SizeCallback, LRUSecondaryCacheTest::SaveToCallback,
    LRUSecondaryCacheTest::DeletionCallback);

Cache::CacheItemHelper LRUSecondaryCacheTest::helper_fail_(
    LRUSecondaryCacheTest::SizeCallback,
    LRUSecondaryCacheTest::SaveToCallbackFail,
    LRUSecondaryCacheTest::DeletionCallback);

TEST_F(LRUSecondaryCacheTest, BasicTest) {
  LRUCacheOptions opts(1024, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
                       kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache =
      std::make_shared<TestSecondaryCache>(2048);
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);
  std::shared_ptr<Statistics> stats = CreateDBStatistics();

  Random rnd(301);
  std::string str1 = rnd.RandomString(1020);
  TestItem* item1 = new TestItem(str1.data(), str1.length());
  ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
                          str1.length()));
  std::string str2 = rnd.RandomString(1020);
  TestItem* item2 = new TestItem(str2.data(), str2.length());
  // k1 should be demoted to NVM
  ASSERT_OK(cache->Insert("k2", item2, &LRUSecondaryCacheTest::helper_,
                          str2.length()));

  get_perf_context()->Reset();
  Cache::Handle* handle;
  handle =
      cache->Lookup("k2", &LRUSecondaryCacheTest::helper_, test_item_creator,
                    Cache::Priority::LOW, true, stats.get());
  ASSERT_NE(handle, nullptr);
  cache->Release(handle);
  // This lookup should promote k1 and demote k2
  handle =
      cache->Lookup("k1", &LRUSecondaryCacheTest::helper_, test_item_creator,
                    Cache::Priority::LOW, true, stats.get());
  ASSERT_NE(handle, nullptr);
  cache->Release(handle);
  ASSERT_EQ(secondary_cache->num_inserts(), 2u);
  ASSERT_EQ(secondary_cache->num_lookups(), 1u);
  ASSERT_EQ(stats->getTickerCount(SECONDARY_CACHE_HITS),
            secondary_cache->num_lookups());
  PerfContext perf_ctx = *get_perf_context();
  ASSERT_EQ(perf_ctx.secondary_cache_hit_count, secondary_cache->num_lookups());

  cache.reset();
  secondary_cache.reset();
}

TEST_F(LRUSecondaryCacheTest, BasicFailTest) {
  LRUCacheOptions opts(1024, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
                       kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache =
      std::make_shared<TestSecondaryCache>(2048);
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);

  Random rnd(301);
  std::string str1 = rnd.RandomString(1020);
  TestItem* item1 = new TestItem(str1.data(), str1.length());
  ASSERT_NOK(cache->Insert("k1", item1, nullptr, str1.length()));
  ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
                          str1.length()));

  Cache::Handle* handle;
  handle = cache->Lookup("k2", nullptr, test_item_creator, Cache::Priority::LOW,
                         true);
  ASSERT_EQ(handle, nullptr);
  handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
                         test_item_creator, Cache::Priority::LOW, false);
  ASSERT_EQ(handle, nullptr);

  cache.reset();
  secondary_cache.reset();
}

TEST_F(LRUSecondaryCacheTest, SaveFailTest) {
  LRUCacheOptions opts(1024, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
                       kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache =
      std::make_shared<TestSecondaryCache>(2048);
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);

  Random rnd(301);
  std::string str1 = rnd.RandomString(1020);
  TestItem* item1 = new TestItem(str1.data(), str1.length());
  ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_fail_,
                          str1.length()));
  std::string str2 = rnd.RandomString(1020);
  TestItem* item2 = new TestItem(str2.data(), str2.length());
  // k1 should be demoted to NVM
  ASSERT_OK(cache->Insert("k2", item2, &LRUSecondaryCacheTest::helper_fail_,
                          str2.length()));

  Cache::Handle* handle;
  handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_fail_,
                         test_item_creator, Cache::Priority::LOW, true);
  ASSERT_NE(handle, nullptr);
  cache->Release(handle);
  // This lookup should fail, since k1 demotion would have failed
  handle = cache->Lookup("k1", &LRUSecondaryCacheTest::helper_fail_,
                         test_item_creator, Cache::Priority::LOW, true);
  ASSERT_EQ(handle, nullptr);
  // Since k1 didn't get promoted, k2 should still be in cache
  handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_fail_,
                         test_item_creator, Cache::Priority::LOW, true);
  ASSERT_NE(handle, nullptr);
  cache->Release(handle);
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 1u);

  cache.reset();
  secondary_cache.reset();
}

TEST_F(LRUSecondaryCacheTest, CreateFailTest) {
  LRUCacheOptions opts(1024, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
                       kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache =
      std::make_shared<TestSecondaryCache>(2048);
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);

  Random rnd(301);
  std::string str1 = rnd.RandomString(1020);
  TestItem* item1 = new TestItem(str1.data(), str1.length());
  ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
                          str1.length()));
  std::string str2 = rnd.RandomString(1020);
  TestItem* item2 = new TestItem(str2.data(), str2.length());
  // k1 should be demoted to NVM
  ASSERT_OK(cache->Insert("k2", item2, &LRUSecondaryCacheTest::helper_,
                          str2.length()));

  Cache::Handle* handle;
  SetFailCreate(true);
  handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
                         test_item_creator, Cache::Priority::LOW, true);
  ASSERT_NE(handle, nullptr);
  cache->Release(handle);
  // This lookup should fail, since k1 creation would have failed
  handle = cache->Lookup("k1", &LRUSecondaryCacheTest::helper_,
                         test_item_creator, Cache::Priority::LOW, true);
  ASSERT_EQ(handle, nullptr);
  // Since k1 didn't get promoted, k2 should still be in cache
  handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
                         test_item_creator, Cache::Priority::LOW, true);
  ASSERT_NE(handle, nullptr);
  cache->Release(handle);
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 1u);

  cache.reset();
  secondary_cache.reset();
}

TEST_F(LRUSecondaryCacheTest, FullCapacityTest) {
  LRUCacheOptions opts(1024, 0, /*_strict_capacity_limit=*/true, 0.5, nullptr,
                       kDefaultToAdaptiveMutex, kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache =
      std::make_shared<TestSecondaryCache>(2048);
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);

  Random rnd(301);
  std::string str1 = rnd.RandomString(1020);
  TestItem* item1 = new TestItem(str1.data(), str1.length());
  ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
                          str1.length()));
  std::string str2 = rnd.RandomString(1020);
  TestItem* item2 = new TestItem(str2.data(), str2.length());
  // k1 should be demoted to NVM
  ASSERT_OK(cache->Insert("k2", item2, &LRUSecondaryCacheTest::helper_,
                          str2.length()));

  Cache::Handle* handle;
  handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
                         test_item_creator, Cache::Priority::LOW, true);
  ASSERT_NE(handle, nullptr);
  // k1 promotion should fail due to the block cache being at capacity,
  // but the lookup should still succeed
  Cache::Handle* handle2;
  handle2 = cache->Lookup("k1", &LRUSecondaryCacheTest::helper_,
                          test_item_creator, Cache::Priority::LOW, true);
  ASSERT_NE(handle2, nullptr);
  // Since k1 didn't get inserted, k2 should still be in cache
  cache->Release(handle);
  cache->Release(handle2);
  handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
                         test_item_creator, Cache::Priority::LOW, true);
  ASSERT_NE(handle, nullptr);
  cache->Release(handle);
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 1u);

  cache.reset();
  secondary_cache.reset();
}

// In this test, the block cache size is set to 4096, after insert 6 KV-pairs
// and flush, there are 5 blocks in this SST file, 2 data blocks and 3 meta
// blocks. block_1 size is 4096 and block_2 size is 2056. The total size
// of the meta blocks are about 900 to 1000. Therefore, in any situation,
// if we try to insert block_1 to the block cache, it will always fails. Only
// block_2 will be successfully inserted into the block cache.
TEST_F(DBSecondaryCacheTest, TestSecondaryCacheCorrectness1) {
  LRUCacheOptions opts(4 * 1024, 0, false, 0.5, nullptr,
                       kDefaultToAdaptiveMutex, kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache(
      new TestSecondaryCache(2048 * 1024));
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);
  BlockBasedTableOptions table_options;
  table_options.block_cache = cache;
  table_options.block_size = 4 * 1024;
  Options options = GetDefaultOptions();
  options.create_if_missing = true;
  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
  options.env = fault_env_.get();
  fault_fs_->SetFailGetUniqueId(true);

  // Set the file paranoid check, so after flush, the file will be read
  // all the blocks will be accessed.
  options.paranoid_file_checks = true;
  DestroyAndReopen(options);
  std::string session_id;
  ASSERT_OK(db_->GetDbSessionId(session_id));
  secondary_cache->SetDbSessionId(session_id);
  Random rnd(301);
  const int N = 6;
  for (int i = 0; i < N; i++) {
    std::string p_v = rnd.RandomString(1007);
    ASSERT_OK(Put(Key(i), p_v));
  }

  ASSERT_OK(Flush());
  // After Flush is successful, RocksDB do the paranoid check for the new
  // SST file. Meta blocks are always cached in the block cache and they
  // will not be evicted. When block_2 is cache miss and read out, it is
  // inserted to the block cache. Note that, block_1 is never successfully
  // inserted to the block cache. Here are 2 lookups in the secondary cache
  // for block_1 and block_2
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 2u);

  Compact("a", "z");
  // Compaction will create the iterator to scan the whole file. So all the
  // blocks are needed. Meta blocks are always cached. When block_1 is read
  // out, block_2 is evicted from block cache and inserted to secondary
  // cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 3u);

  std::string v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // The first data block is not in the cache, similarly, trigger the block
  // cache Lookup and secondary cache lookup for block_1. But block_1 will not
  // be inserted successfully due to the size. Currently, cache only has
  // the meta blocks.
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 4u);

  v = Get(Key(5));
  ASSERT_EQ(1007, v.size());
  // The second data block is not in the cache, similarly, trigger the block
  // cache Lookup and secondary cache lookup for block_2 and block_2 is found
  // in the secondary cache. Now block cache has block_2
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 5u);

  v = Get(Key(5));
  ASSERT_EQ(1007, v.size());
  // block_2 is in the block cache. There is a block cache hit. No need to
  // lookup or insert the secondary cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 5u);

  v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // Lookup the first data block, not in the block cache, so lookup the
  // secondary cache. Also not in the secondary cache. After Get, still
  // block_1 is will not be cached.
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 6u);

  v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // Lookup the first data block, not in the block cache, so lookup the
  // secondary cache. Also not in the secondary cache. After Get, still
  // block_1 is will not be cached.
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 7u);

  Destroy(options);
}

// In this test, the block cache size is set to 6100, after insert 6 KV-pairs
// and flush, there are 5 blocks in this SST file, 2 data blocks and 3 meta
// blocks. block_1 size is 4096 and block_2 size is 2056. The total size
// of the meta blocks are about 900 to 1000. Therefore, we can successfully
// insert and cache block_1 in the block cache (this is the different place
// from TestSecondaryCacheCorrectness1)
TEST_F(DBSecondaryCacheTest, TestSecondaryCacheCorrectness2) {
  LRUCacheOptions opts(6100, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
                       kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache(
      new TestSecondaryCache(2048 * 1024));
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);
  BlockBasedTableOptions table_options;
  table_options.block_cache = cache;
  table_options.block_size = 4 * 1024;
  Options options = GetDefaultOptions();
  options.create_if_missing = true;
  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
  options.paranoid_file_checks = true;
  options.env = fault_env_.get();
  fault_fs_->SetFailGetUniqueId(true);
  DestroyAndReopen(options);
  std::string session_id;
  ASSERT_OK(db_->GetDbSessionId(session_id));
  secondary_cache->SetDbSessionId(session_id);
  Random rnd(301);
  const int N = 6;
  for (int i = 0; i < N; i++) {
    std::string p_v = rnd.RandomString(1007);
    ASSERT_OK(Put(Key(i), p_v));
  }

  ASSERT_OK(Flush());
  // After Flush is successful, RocksDB do the paranoid check for the new
  // SST file. Meta blocks are always cached in the block cache and they
  // will not be evicted. When block_2 is cache miss and read out, it is
  // inserted to the block cache. Thefore, block_1 is evicted from block
  // cache and successfully inserted to the secondary cache. Here are 2
  // lookups in the secondary cache for block_1 and block_2.
  ASSERT_EQ(secondary_cache->num_inserts(), 1u);
  ASSERT_EQ(secondary_cache->num_lookups(), 2u);

  Compact("a", "z");
  // Compaction will create the iterator to scan the whole file. So all the
  // blocks are needed. After Flush, only block_2 is cached in block cache
  // and block_1 is in the secondary cache. So when read block_1, it is
  // read out from secondary cache and inserted to block cache. At the same
  // time, block_2 is inserted to secondary cache. Now, secondary cache has
  // both block_1 and block_2. After compaction, block_1 is in the cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 2u);
  ASSERT_EQ(secondary_cache->num_lookups(), 3u);

  std::string v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // This Get needs to access block_1, since block_1 is cached in block cache
  // there is no secondary cache lookup.
  ASSERT_EQ(secondary_cache->num_inserts(), 2u);
  ASSERT_EQ(secondary_cache->num_lookups(), 3u);

  v = Get(Key(5));
  ASSERT_EQ(1007, v.size());
  // This Get needs to access block_2 which is not in the block cache. So
  // it will lookup the secondary cache for block_2 and cache it in the
  // block_cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 2u);
  ASSERT_EQ(secondary_cache->num_lookups(), 4u);

  v = Get(Key(5));
  ASSERT_EQ(1007, v.size());
  // This Get needs to access block_2 which is already in the block cache.
  // No need to lookup secondary cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 2u);
  ASSERT_EQ(secondary_cache->num_lookups(), 4u);

  v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // This Get needs to access block_1, since block_1 is not in block cache
  // there is one econdary cache lookup. Then, block_1 is cached in the
  // block cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 2u);
  ASSERT_EQ(secondary_cache->num_lookups(), 5u);

  v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // This Get needs to access block_1, since block_1 is cached in block cache
  // there is no secondary cache lookup.
  ASSERT_EQ(secondary_cache->num_inserts(), 2u);
  ASSERT_EQ(secondary_cache->num_lookups(), 5u);

  Destroy(options);
}

// The block cache size is set to 1024*1024, after insert 6 KV-pairs
// and flush, there are 5 blocks in this SST file, 2 data blocks and 3 meta
// blocks. block_1 size is 4096 and block_2 size is 2056. The total size
// of the meta blocks are about 900 to 1000. Therefore, we can successfully
// cache all the blocks in the block cache and there is not secondary cache
// insertion. 2 lookup is needed for the blocks.
TEST_F(DBSecondaryCacheTest, NoSecondaryCacheInsertion) {
  LRUCacheOptions opts(1024 * 1024, 0, false, 0.5, nullptr,
                       kDefaultToAdaptiveMutex, kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache(
      new TestSecondaryCache(2048 * 1024));
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);
  BlockBasedTableOptions table_options;
  table_options.block_cache = cache;
  table_options.block_size = 4 * 1024;
  Options options = GetDefaultOptions();
  options.create_if_missing = true;
  options.paranoid_file_checks = true;
  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
  options.env = fault_env_.get();
  fault_fs_->SetFailGetUniqueId(true);

  DestroyAndReopen(options);
  std::string session_id;
  ASSERT_OK(db_->GetDbSessionId(session_id));
  secondary_cache->SetDbSessionId(session_id);
  Random rnd(301);
  const int N = 6;
  for (int i = 0; i < N; i++) {
    std::string p_v = rnd.RandomString(1000);
    ASSERT_OK(Put(Key(i), p_v));
  }

  ASSERT_OK(Flush());
  // After Flush is successful, RocksDB do the paranoid check for the new
  // SST file. Meta blocks are always cached in the block cache and they
  // will not be evicted. Now, block cache is large enough, it cache
  // both block_1 and block_2. When first time read block_1 and block_2
  // there are cache misses. So 2 secondary cache lookups are needed for
  // the 2 blocks
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 2u);

  Compact("a", "z");
  // Compaction will iterate the whole SST file. Since all the data blocks
  // are in the block cache. No need to lookup the secondary cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 2u);

  std::string v = Get(Key(0));
  ASSERT_EQ(1000, v.size());
  // Since the block cache is large enough, all the blocks are cached. we
  // do not need to lookup the seondary cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 2u);

  Destroy(options);
}

TEST_F(DBSecondaryCacheTest, SecondaryCacheIntensiveTesting) {
  LRUCacheOptions opts(8 * 1024, 0, false, 0.5, nullptr,
                       kDefaultToAdaptiveMutex, kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache(
      new TestSecondaryCache(2048 * 1024));
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);
  BlockBasedTableOptions table_options;
  table_options.block_cache = cache;
  table_options.block_size = 4 * 1024;
  Options options = GetDefaultOptions();
  options.create_if_missing = true;
  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
  options.env = fault_env_.get();
  fault_fs_->SetFailGetUniqueId(true);
  DestroyAndReopen(options);
  std::string session_id;
  ASSERT_OK(db_->GetDbSessionId(session_id));
  secondary_cache->SetDbSessionId(session_id);
  Random rnd(301);
  const int N = 256;
  for (int i = 0; i < N; i++) {
    std::string p_v = rnd.RandomString(1000);
    ASSERT_OK(Put(Key(i), p_v));
  }
  ASSERT_OK(Flush());
  Compact("a", "z");

  Random r_index(47);
  std::string v;
  for (int i = 0; i < 1000; i++) {
    uint32_t key_i = r_index.Next() % N;
    v = Get(Key(key_i));
  }

  // We have over 200 data blocks there will be multiple insertion
  // and lookups.
  ASSERT_GE(secondary_cache->num_inserts(), 1u);
  ASSERT_GE(secondary_cache->num_lookups(), 1u);

  Destroy(options);
}

// In this test, the block cache size is set to 4096, after insert 6 KV-pairs
// and flush, there are 5 blocks in this SST file, 2 data blocks and 3 meta
// blocks. block_1 size is 4096 and block_2 size is 2056. The total size
// of the meta blocks are about 900 to 1000. Therefore, in any situation,
// if we try to insert block_1 to the block cache, it will always fails. Only
// block_2 will be successfully inserted into the block cache.
TEST_F(DBSecondaryCacheTest, SecondaryCacheFailureTest) {
  LRUCacheOptions opts(4 * 1024, 0, false, 0.5, nullptr,
                       kDefaultToAdaptiveMutex, kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache(
      new TestSecondaryCache(2048 * 1024));
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);
  BlockBasedTableOptions table_options;
  table_options.block_cache = cache;
  table_options.block_size = 4 * 1024;
  Options options = GetDefaultOptions();
  options.create_if_missing = true;
  options.paranoid_file_checks = true;
  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
  options.env = fault_env_.get();
  fault_fs_->SetFailGetUniqueId(true);
  DestroyAndReopen(options);
  std::string session_id;
  ASSERT_OK(db_->GetDbSessionId(session_id));
  secondary_cache->SetDbSessionId(session_id);
  Random rnd(301);
  const int N = 6;
  for (int i = 0; i < N; i++) {
    std::string p_v = rnd.RandomString(1007);
    ASSERT_OK(Put(Key(i), p_v));
  }

  ASSERT_OK(Flush());
  // After Flush is successful, RocksDB do the paranoid check for the new
  // SST file. Meta blocks are always cached in the block cache and they
  // will not be evicted. When block_2 is cache miss and read out, it is
  // inserted to the block cache. Note that, block_1 is never successfully
  // inserted to the block cache. Here are 2 lookups in the secondary cache
  // for block_1 and block_2
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 2u);

  // Fail the insertion, in LRU cache, the secondary insertion returned status
  // is not checked, therefore, the DB will not be influenced.
  secondary_cache->InjectFailure();
  Compact("a", "z");
  // Compaction will create the iterator to scan the whole file. So all the
  // blocks are needed. Meta blocks are always cached. When block_1 is read
  // out, block_2 is evicted from block cache and inserted to secondary
  // cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 3u);

  std::string v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // The first data block is not in the cache, similarly, trigger the block
  // cache Lookup and secondary cache lookup for block_1. But block_1 will not
  // be inserted successfully due to the size. Currently, cache only has
  // the meta blocks.
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 4u);

  v = Get(Key(5));
  ASSERT_EQ(1007, v.size());
  // The second data block is not in the cache, similarly, trigger the block
  // cache Lookup and secondary cache lookup for block_2 and block_2 is found
  // in the secondary cache. Now block cache has block_2
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 5u);

  v = Get(Key(5));
  ASSERT_EQ(1007, v.size());
  // block_2 is in the block cache. There is a block cache hit. No need to
  // lookup or insert the secondary cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 5u);

  v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // Lookup the first data block, not in the block cache, so lookup the
  // secondary cache. Also not in the secondary cache. After Get, still
  // block_1 is will not be cached.
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 6u);

  v = Get(Key(0));
  ASSERT_EQ(1007, v.size());
  // Lookup the first data block, not in the block cache, so lookup the
  // secondary cache. Also not in the secondary cache. After Get, still
  // block_1 is will not be cached.
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 7u);
  secondary_cache->ResetInjectFailure();

  Destroy(options);
}

TEST_F(LRUSecondaryCacheTest, BasicWaitAllTest) {
  LRUCacheOptions opts(1024, 2, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
                       kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache =
      std::make_shared<TestSecondaryCache>(32 * 1024);
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);
  const int num_keys = 32;

  Random rnd(301);
  std::vector<std::string> values;
  for (int i = 0; i < num_keys; ++i) {
    std::string str = rnd.RandomString(1020);
    values.emplace_back(str);
    TestItem* item = new TestItem(str.data(), str.length());
    ASSERT_OK(cache->Insert("k" + std::to_string(i), item,
                            &LRUSecondaryCacheTest::helper_, str.length()));
  }
  // Force all entries to be evicted to the secondary cache
  cache->SetCapacity(0);
  ASSERT_EQ(secondary_cache->num_inserts(), 32u);
  cache->SetCapacity(32 * 1024);

  secondary_cache->SetResultMap(
      {{"k3", TestSecondaryCache::ResultType::DEFER},
       {"k4", TestSecondaryCache::ResultType::DEFER_AND_FAIL},
       {"k5", TestSecondaryCache::ResultType::FAIL}});
  std::vector<Cache::Handle*> results;
  for (int i = 0; i < 6; ++i) {
    results.emplace_back(
        cache->Lookup("k" + std::to_string(i), &LRUSecondaryCacheTest::helper_,
                      test_item_creator, Cache::Priority::LOW, false));
  }
  cache->WaitAll(results);
  for (int i = 0; i < 6; ++i) {
    if (i == 4) {
      ASSERT_EQ(cache->Value(results[i]), nullptr);
    } else if (i == 5) {
      ASSERT_EQ(results[i], nullptr);
      continue;
    } else {
      TestItem* item = static_cast<TestItem*>(cache->Value(results[i]));
      ASSERT_EQ(item->ToString(), values[i]);
    }
    cache->Release(results[i]);
  }

  cache.reset();
  secondary_cache.reset();
}

// In this test, we have one KV pair per data block. We indirectly determine
// the cache key associated with each data block (and thus each KV) by using
// a sync point callback in TestSecondaryCache::Lookup. We then control the
// lookup result by setting the ResultMap.
TEST_F(DBSecondaryCacheTest, TestSecondaryCacheMultiGet) {
  LRUCacheOptions opts(1 << 20, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
                       kDontChargeCacheMetadata);
  std::shared_ptr<TestSecondaryCache> secondary_cache(
      new TestSecondaryCache(2048 * 1024));
  opts.secondary_cache = secondary_cache;
  std::shared_ptr<Cache> cache = NewLRUCache(opts);
  BlockBasedTableOptions table_options;
  table_options.block_cache = cache;
  table_options.block_size = 4 * 1024;
  table_options.cache_index_and_filter_blocks = false;
  Options options = GetDefaultOptions();
  options.create_if_missing = true;
  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
  options.paranoid_file_checks = true;
  DestroyAndReopen(options);
  Random rnd(301);
  const int N = 8;
  std::vector<std::string> keys;
  for (int i = 0; i < N; i++) {
    std::string p_v = rnd.RandomString(4000);
    keys.emplace_back(p_v);
    ASSERT_OK(Put(Key(i), p_v));
  }

  ASSERT_OK(Flush());
  // After Flush is successful, RocksDB does the paranoid check for the new
  // SST file. This will try to lookup all data blocks in the secondary
  // cache.
  ASSERT_EQ(secondary_cache->num_inserts(), 0u);
  ASSERT_EQ(secondary_cache->num_lookups(), 8u);

  cache->SetCapacity(0);
  ASSERT_EQ(secondary_cache->num_inserts(), 8u);
  cache->SetCapacity(1 << 20);

  std::vector<std::string> cache_keys;
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
      "TestSecondaryCache::Lookup", [&cache_keys](void* key) -> void {
        cache_keys.emplace_back(*(static_cast<std::string*>(key)));
      });
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
  for (int i = 0; i < N; ++i) {
    std::string v = Get(Key(i));
    ASSERT_EQ(4000, v.size());
    ASSERT_EQ(v, keys[i]);
  }
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->DisableProcessing();
  ASSERT_EQ(secondary_cache->num_lookups(), 16u);
  cache->SetCapacity(0);
  cache->SetCapacity(1 << 20);

  ASSERT_EQ(Get(Key(2)), keys[2]);
  ASSERT_EQ(Get(Key(7)), keys[7]);
  secondary_cache->SetResultMap(
      {{cache_keys[3], TestSecondaryCache::ResultType::DEFER},
       {cache_keys[4], TestSecondaryCache::ResultType::DEFER_AND_FAIL},
       {cache_keys[5], TestSecondaryCache::ResultType::FAIL}});

  std::vector<std::string> mget_keys(
      {Key(0), Key(1), Key(2), Key(3), Key(4), Key(5), Key(6), Key(7)});
  std::vector<PinnableSlice> values(mget_keys.size());
  std::vector<Status> s(keys.size());
  std::vector<Slice> key_slices;
  for (const std::string& key : mget_keys) {
    key_slices.emplace_back(key);
  }
  uint32_t num_lookups = secondary_cache->num_lookups();
  dbfull()->MultiGet(ReadOptions(), dbfull()->DefaultColumnFamily(),
                     key_slices.size(), key_slices.data(), values.data(),
                     s.data(), false);
  ASSERT_EQ(secondary_cache->num_lookups(), num_lookups + 5);
  for (int i = 0; i < N; ++i) {
    ASSERT_OK(s[i]);
    ASSERT_EQ(values[i].ToString(), keys[i]);
    values[i].Reset();
  }
  Destroy(options);
}

}  // namespace ROCKSDB_NAMESPACE

int main(int argc, char** argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}