aboutsummaryrefslogtreecommitdiff
path: root/util/cache_test.cc
blob: 468f7a6425bfa92ff05bb412202846ddc263f8f8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
// 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 "leveldb/cache.h"

#include <vector>
#include "util/coding.h"
#include "util/testharness.h"

namespace leveldb {

// Conversions between numeric keys/values and the types expected by Cache.
static std::string EncodeKey(int k) {
  std::string result;
  PutFixed32(&result, k);
  return result;
}
static int DecodeKey(const Slice& k) {
  assert(k.size() == 4);
  return DecodeFixed32(k.data());
}
static void* EncodeValue(uintptr_t v) { return reinterpret_cast<void*>(v); }
static int DecodeValue(void* v) { return reinterpret_cast<uintptr_t>(v); }

class CacheTest {
 public:
  static CacheTest* current_;

  static void Deleter(const Slice& key, void* v) {
    current_->deleted_keys_.push_back(DecodeKey(key));
    current_->deleted_values_.push_back(DecodeValue(v));
  }

  static const int kCacheSize = 1000;
  std::vector<int> deleted_keys_;
  std::vector<int> deleted_values_;
  Cache* cache_;

  CacheTest() : cache_(NewLRUCache(kCacheSize)) {
    current_ = this;
  }

  ~CacheTest() {
    delete cache_;
  }

  int Lookup(int key) {
    Cache::Handle* handle = cache_->Lookup(EncodeKey(key));
    const int r = (handle == NULL) ? -1 : DecodeValue(cache_->Value(handle));
    if (handle != NULL) {
      cache_->Release(handle);
    }
    return r;
  }

  void Insert(int key, int value, int charge = 1) {
    cache_->Release(cache_->Insert(EncodeKey(key), EncodeValue(value), charge,
                                   &CacheTest::Deleter));
  }

  Cache::Handle* InsertAndReturnHandle(int key, int value, int charge = 1) {
    return cache_->Insert(EncodeKey(key), EncodeValue(value), charge,
                          &CacheTest::Deleter);
  }

  void Erase(int key) {
    cache_->Erase(EncodeKey(key));
  }
};
CacheTest* CacheTest::current_;

TEST(CacheTest, HitAndMiss) {
  ASSERT_EQ(-1, Lookup(100));

  Insert(100, 101);
  ASSERT_EQ(101, Lookup(100));
  ASSERT_EQ(-1,  Lookup(200));
  ASSERT_EQ(-1,  Lookup(300));

  Insert(200, 201);
  ASSERT_EQ(101, Lookup(100));
  ASSERT_EQ(201, Lookup(200));
  ASSERT_EQ(-1,  Lookup(300));

  Insert(100, 102);
  ASSERT_EQ(102, Lookup(100));
  ASSERT_EQ(201, Lookup(200));
  ASSERT_EQ(-1,  Lookup(300));

  ASSERT_EQ(1, deleted_keys_.size());
  ASSERT_EQ(100, deleted_keys_[0]);
  ASSERT_EQ(101, deleted_values_[0]);
}

TEST(CacheTest, Erase) {
  Erase(200);
  ASSERT_EQ(0, deleted_keys_.size());

  Insert(100, 101);
  Insert(200, 201);
  Erase(100);
  ASSERT_EQ(-1,  Lookup(100));
  ASSERT_EQ(201, Lookup(200));
  ASSERT_EQ(1, deleted_keys_.size());
  ASSERT_EQ(100, deleted_keys_[0]);
  ASSERT_EQ(101, deleted_values_[0]);

  Erase(100);
  ASSERT_EQ(-1,  Lookup(100));
  ASSERT_EQ(201, Lookup(200));
  ASSERT_EQ(1, deleted_keys_.size());
}

TEST(CacheTest, EntriesArePinned) {
  Insert(100, 101);
  Cache::Handle* h1 = cache_->Lookup(EncodeKey(100));
  ASSERT_EQ(101, DecodeValue(cache_->Value(h1)));

  Insert(100, 102);
  Cache::Handle* h2 = cache_->Lookup(EncodeKey(100));
  ASSERT_EQ(102, DecodeValue(cache_->Value(h2)));
  ASSERT_EQ(0, deleted_keys_.size());

  cache_->Release(h1);
  ASSERT_EQ(1, deleted_keys_.size());
  ASSERT_EQ(100, deleted_keys_[0]);
  ASSERT_EQ(101, deleted_values_[0]);

  Erase(100);
  ASSERT_EQ(-1, Lookup(100));
  ASSERT_EQ(1, deleted_keys_.size());

  cache_->Release(h2);
  ASSERT_EQ(2, deleted_keys_.size());
  ASSERT_EQ(100, deleted_keys_[1]);
  ASSERT_EQ(102, deleted_values_[1]);
}

TEST(CacheTest, EvictionPolicy) {
  Insert(100, 101);
  Insert(200, 201);
  Insert(300, 301);
  Cache::Handle* h = cache_->Lookup(EncodeKey(300));

  // Frequently used entry must be kept around,
  // as must things that are still in use.
  for (int i = 0; i < kCacheSize + 100; i++) {
    Insert(1000+i, 2000+i);
    ASSERT_EQ(2000+i, Lookup(1000+i));
    ASSERT_EQ(101, Lookup(100));
  }
  ASSERT_EQ(101, Lookup(100));
  ASSERT_EQ(-1, Lookup(200));
  ASSERT_EQ(301, Lookup(300));
  cache_->Release(h);
}

TEST(CacheTest, UseExceedsCacheSize) {
  // Overfill the cache, keeping handles on all inserted entries.
  std::vector<Cache::Handle*> h;
  for (int i = 0; i < kCacheSize + 100; i++) {
    h.push_back(InsertAndReturnHandle(1000+i, 2000+i));
  }

  // Check that all the entries can be found in the cache.
  for (int i = 0; i < h.size(); i++) {
    ASSERT_EQ(2000+i, Lookup(1000+i));
  }

  for (int i = 0; i < h.size(); i++) {
    cache_->Release(h[i]);
  }
}

TEST(CacheTest, HeavyEntries) {
  // Add a bunch of light and heavy entries and then count the combined
  // size of items still in the cache, which must be approximately the
  // same as the total capacity.
  const int kLight = 1;
  const int kHeavy = 10;
  int added = 0;
  int index = 0;
  while (added < 2*kCacheSize) {
    const int weight = (index & 1) ? kLight : kHeavy;
    Insert(index, 1000+index, weight);
    added += weight;
    index++;
  }

  int cached_weight = 0;
  for (int i = 0; i < index; i++) {
    const int weight = (i & 1 ? kLight : kHeavy);
    int r = Lookup(i);
    if (r >= 0) {
      cached_weight += weight;
      ASSERT_EQ(1000+i, r);
    }
  }
  ASSERT_LE(cached_weight, kCacheSize + kCacheSize/10);
}

TEST(CacheTest, NewId) {
  uint64_t a = cache_->NewId();
  uint64_t b = cache_->NewId();
  ASSERT_NE(a, b);
}

TEST(CacheTest, Prune) {
  Insert(1, 100);
  Insert(2, 200);

  Cache::Handle* handle = cache_->Lookup(EncodeKey(1));
  ASSERT_TRUE(handle);
  cache_->Prune();
  cache_->Release(handle);

  ASSERT_EQ(100, Lookup(1));
  ASSERT_EQ(-1, Lookup(2));
}

}  // namespace leveldb

int main(int argc, char** argv) {
  return leveldb::test::RunAllTests();
}