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224 righe
5.7 KiB
224 righe
5.7 KiB
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "leveldb/cache.h"
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#include <vector>
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#include "gtest/gtest.h"
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#include "util/coding.h"
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namespace leveldb {
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// Conversions between numeric keys/values and the types expected by Cache.
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static std::string EncodeKey(int k) {
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std::string result;
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PutFixed32(&result, k);
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return result;
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}
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static int DecodeKey(const Slice& k) {
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assert(k.size() == 4);
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return DecodeFixed32(k.data());
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}
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static void* EncodeValue(uintptr_t v) { return reinterpret_cast<void*>(v); }
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static int DecodeValue(void* v) { return reinterpret_cast<uintptr_t>(v); }
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class CacheTest : public testing::Test {
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public:
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static void Deleter(const Slice& key, void* v) {
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current_->deleted_keys_.push_back(DecodeKey(key));
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current_->deleted_values_.push_back(DecodeValue(v));
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}
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static constexpr int kCacheSize = 1000;
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std::vector<int> deleted_keys_;
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std::vector<int> deleted_values_;
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Cache* cache_;
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CacheTest() : cache_(NewLRUCache(kCacheSize)) { current_ = this; }
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~CacheTest() { delete cache_; }
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int Lookup(int key) {
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Cache::Handle* handle = cache_->Lookup(EncodeKey(key));
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const int r = (handle == nullptr) ? -1 : DecodeValue(cache_->Value(handle));
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if (handle != nullptr) {
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cache_->Release(handle);
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}
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return r;
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}
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void Insert(int key, int value, int charge = 1) {
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cache_->Release(cache_->Insert(EncodeKey(key), EncodeValue(value), charge,
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&CacheTest::Deleter));
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}
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Cache::Handle* InsertAndReturnHandle(int key, int value, int charge = 1) {
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return cache_->Insert(EncodeKey(key), EncodeValue(value), charge,
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&CacheTest::Deleter);
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}
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void Erase(int key) { cache_->Erase(EncodeKey(key)); }
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static CacheTest* current_;
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};
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CacheTest* CacheTest::current_;
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TEST_F(CacheTest, HitAndMiss) {
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ASSERT_EQ(-1, Lookup(100));
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Insert(100, 101);
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ASSERT_EQ(101, Lookup(100));
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ASSERT_EQ(-1, Lookup(200));
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ASSERT_EQ(-1, Lookup(300));
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Insert(200, 201);
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ASSERT_EQ(101, Lookup(100));
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ASSERT_EQ(201, Lookup(200));
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ASSERT_EQ(-1, Lookup(300));
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Insert(100, 102);
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ASSERT_EQ(102, Lookup(100));
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ASSERT_EQ(201, Lookup(200));
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ASSERT_EQ(-1, Lookup(300));
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ASSERT_EQ(1, deleted_keys_.size());
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ASSERT_EQ(100, deleted_keys_[0]);
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ASSERT_EQ(101, deleted_values_[0]);
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}
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TEST_F(CacheTest, Erase) {
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Erase(200);
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ASSERT_EQ(0, deleted_keys_.size());
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Insert(100, 101);
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Insert(200, 201);
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Erase(100);
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ASSERT_EQ(-1, Lookup(100));
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ASSERT_EQ(201, Lookup(200));
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ASSERT_EQ(1, deleted_keys_.size());
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ASSERT_EQ(100, deleted_keys_[0]);
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ASSERT_EQ(101, deleted_values_[0]);
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Erase(100);
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ASSERT_EQ(-1, Lookup(100));
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ASSERT_EQ(201, Lookup(200));
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ASSERT_EQ(1, deleted_keys_.size());
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}
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TEST_F(CacheTest, EntriesArePinned) {
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Insert(100, 101);
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Cache::Handle* h1 = cache_->Lookup(EncodeKey(100));
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ASSERT_EQ(101, DecodeValue(cache_->Value(h1)));
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Insert(100, 102);
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Cache::Handle* h2 = cache_->Lookup(EncodeKey(100));
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ASSERT_EQ(102, DecodeValue(cache_->Value(h2)));
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ASSERT_EQ(0, deleted_keys_.size());
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cache_->Release(h1);
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ASSERT_EQ(1, deleted_keys_.size());
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ASSERT_EQ(100, deleted_keys_[0]);
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ASSERT_EQ(101, deleted_values_[0]);
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Erase(100);
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ASSERT_EQ(-1, Lookup(100));
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ASSERT_EQ(1, deleted_keys_.size());
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cache_->Release(h2);
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ASSERT_EQ(2, deleted_keys_.size());
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ASSERT_EQ(100, deleted_keys_[1]);
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ASSERT_EQ(102, deleted_values_[1]);
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}
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TEST_F(CacheTest, EvictionPolicy) {
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Insert(100, 101);
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Insert(200, 201);
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Insert(300, 301);
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Cache::Handle* h = cache_->Lookup(EncodeKey(300));
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// Frequently used entry must be kept around,
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// as must things that are still in use.
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for (int i = 0; i < kCacheSize + 100; i++) {
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Insert(1000 + i, 2000 + i);
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ASSERT_EQ(2000 + i, Lookup(1000 + i));
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ASSERT_EQ(101, Lookup(100));
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}
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ASSERT_EQ(101, Lookup(100));
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ASSERT_EQ(-1, Lookup(200));
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ASSERT_EQ(301, Lookup(300));
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cache_->Release(h);
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}
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TEST_F(CacheTest, UseExceedsCacheSize) {
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// Overfill the cache, keeping handles on all inserted entries.
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std::vector<Cache::Handle*> h;
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for (int i = 0; i < kCacheSize + 100; i++) {
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h.push_back(InsertAndReturnHandle(1000 + i, 2000 + i));
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}
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// Check that all the entries can be found in the cache.
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for (int i = 0; i < h.size(); i++) {
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ASSERT_EQ(2000 + i, Lookup(1000 + i));
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}
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for (int i = 0; i < h.size(); i++) {
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cache_->Release(h[i]);
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}
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}
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TEST_F(CacheTest, HeavyEntries) {
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// Add a bunch of light and heavy entries and then count the combined
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// size of items still in the cache, which must be approximately the
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// same as the total capacity.
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const int kLight = 1;
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const int kHeavy = 10;
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int added = 0;
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int index = 0;
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while (added < 2 * kCacheSize) {
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const int weight = (index & 1) ? kLight : kHeavy;
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Insert(index, 1000 + index, weight);
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added += weight;
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index++;
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}
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int cached_weight = 0;
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for (int i = 0; i < index; i++) {
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const int weight = (i & 1 ? kLight : kHeavy);
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int r = Lookup(i);
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if (r >= 0) {
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cached_weight += weight;
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ASSERT_EQ(1000 + i, r);
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}
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}
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ASSERT_LE(cached_weight, kCacheSize + kCacheSize / 10);
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}
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TEST_F(CacheTest, NewId) {
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uint64_t a = cache_->NewId();
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uint64_t b = cache_->NewId();
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ASSERT_NE(a, b);
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}
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TEST_F(CacheTest, Prune) {
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Insert(1, 100);
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Insert(2, 200);
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Cache::Handle* handle = cache_->Lookup(EncodeKey(1));
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ASSERT_TRUE(handle);
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cache_->Prune();
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cache_->Release(handle);
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ASSERT_EQ(100, Lookup(1));
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ASSERT_EQ(-1, Lookup(2));
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}
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TEST_F(CacheTest, ZeroSizeCache) {
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delete cache_;
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cache_ = NewLRUCache(0);
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Insert(1, 100);
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ASSERT_EQ(-1, Lookup(1));
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}
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} // namespace leveldb
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