rocksdb/util/cache_test.cc
Yi Wu badbff65b7 Not insert into block cache if cache is full and not holding handle
Summary:
We used to allow insert into full block cache as long as `strict_capacity_limit=false`. This diff further restrict insert to full cache if caller don't intent to hold handle to the cache entry after insert.

Hope this diff fix the assertion failure with db_stress: https://our.intern.facebook.com/intern/sandcastle/log/?instance_id=211853102&step_id=2475070014

  db_stress: util/lru_cache.cc:278: virtual void rocksdb::LRUCacheShard::Release(rocksdb::Cache::Handle*): Assertion `lru_.next == &lru_' failed.

The assertion at lru_cache.cc:278 can fail when an entry is inserted into full cache and stay in LRU list.

Test Plan:
  make all check

Reviewers: IslamAbdelRahman, lightmark, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D62325
2016-08-23 13:53:49 -07:00

616 lines
17 KiB
C++

// Copyright (c) 2011-present, 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.
//
// 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 "rocksdb/cache.h"
#include <forward_list>
#include <functional>
#include <iostream>
#include <string>
#include <vector>
#include "util/clock_cache.h"
#include "util/coding.h"
#include "util/string_util.h"
#include "util/testharness.h"
namespace rocksdb {
// 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 static_cast<int>(reinterpret_cast<uintptr_t>(v));
}
typedef std::function<std::shared_ptr<Cache>(size_t, int, bool)> NewCache;
void dumbDeleter(const Slice& key, void* value) {}
void eraseDeleter(const Slice& key, void* value) {
Cache* cache = reinterpret_cast<Cache*>(value);
cache->Erase("foo");
}
class CacheTest : public testing::TestWithParam<NewCache> {
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;
static const int kNumShardBits = 4;
static const int kCacheSize2 = 100;
static const int kNumShardBits2 = 2;
std::vector<int> deleted_keys_;
std::vector<int> deleted_values_;
shared_ptr<Cache> cache_;
shared_ptr<Cache> cache2_;
CacheTest()
: cache_(GetNewCache()(kCacheSize, kNumShardBits, false)),
cache2_(GetNewCache()(kCacheSize2, kNumShardBits2, false)) {
current_ = this;
}
~CacheTest() {
}
NewCache GetNewCache() { return GetParam(); }
int Lookup(shared_ptr<Cache> cache, int key) {
Cache::Handle* handle = cache->Lookup(EncodeKey(key));
const int r = (handle == nullptr) ? -1 : DecodeValue(cache->Value(handle));
if (handle != nullptr) {
cache->Release(handle);
}
return r;
}
void Insert(shared_ptr<Cache> cache, int key, int value, int charge = 1) {
cache->Insert(EncodeKey(key), EncodeValue(value), charge,
&CacheTest::Deleter);
}
void Erase(shared_ptr<Cache> cache, int key) {
cache->Erase(EncodeKey(key));
}
int Lookup(int key) {
return Lookup(cache_, key);
}
void Insert(int key, int value, int charge = 1) {
Insert(cache_, key, value, charge);
}
void Erase(int key) {
Erase(cache_, key);
}
int Lookup2(int key) {
return Lookup(cache2_, key);
}
void Insert2(int key, int value, int charge = 1) {
Insert(cache2_, key, value, charge);
}
void Erase2(int key) {
Erase(cache2_, key);
}
};
CacheTest* CacheTest::current_;
TEST_P(CacheTest, UsageTest) {
// cache is shared_ptr and will be automatically cleaned up.
const uint64_t kCapacity = 100000;
auto cache = GetNewCache()(kCapacity, 8, false);
size_t usage = 0;
char value[10] = "abcdef";
// make sure everything will be cached
for (int i = 1; i < 100; ++i) {
std::string key(i, 'a');
auto kv_size = key.size() + 5;
cache->Insert(key, reinterpret_cast<void*>(value), kv_size, dumbDeleter);
usage += kv_size;
ASSERT_EQ(usage, cache->GetUsage());
}
// make sure the cache will be overloaded
for (uint64_t i = 1; i < kCapacity; ++i) {
auto key = ToString(i);
cache->Insert(key, reinterpret_cast<void*>(value), key.size() + 5,
dumbDeleter);
}
// the usage should be close to the capacity
ASSERT_GT(kCapacity, cache->GetUsage());
ASSERT_LT(kCapacity * 0.95, cache->GetUsage());
}
TEST_P(CacheTest, PinnedUsageTest) {
// cache is shared_ptr and will be automatically cleaned up.
const uint64_t kCapacity = 100000;
auto cache = GetNewCache()(kCapacity, 8, false);
size_t pinned_usage = 0;
char value[10] = "abcdef";
std::forward_list<Cache::Handle*> unreleased_handles;
// Add entries. Unpin some of them after insertion. Then, pin some of them
// again. Check GetPinnedUsage().
for (int i = 1; i < 100; ++i) {
std::string key(i, 'a');
auto kv_size = key.size() + 5;
Cache::Handle* handle;
cache->Insert(key, reinterpret_cast<void*>(value), kv_size, dumbDeleter,
&handle);
pinned_usage += kv_size;
ASSERT_EQ(pinned_usage, cache->GetPinnedUsage());
if (i % 2 == 0) {
cache->Release(handle);
pinned_usage -= kv_size;
ASSERT_EQ(pinned_usage, cache->GetPinnedUsage());
} else {
unreleased_handles.push_front(handle);
}
if (i % 3 == 0) {
unreleased_handles.push_front(cache->Lookup(key));
// If i % 2 == 0, then the entry was unpinned before Lookup, so pinned
// usage increased
if (i % 2 == 0) {
pinned_usage += kv_size;
}
ASSERT_EQ(pinned_usage, cache->GetPinnedUsage());
}
}
// check that overloading the cache does not change the pinned usage
for (uint64_t i = 1; i < 2 * kCapacity; ++i) {
auto key = ToString(i);
cache->Insert(key, reinterpret_cast<void*>(value), key.size() + 5,
dumbDeleter);
}
ASSERT_EQ(pinned_usage, cache->GetPinnedUsage());
// release handles for pinned entries to prevent memory leaks
for (auto handle : unreleased_handles) {
cache->Release(handle);
}
}
TEST_P(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(1U, deleted_keys_.size());
ASSERT_EQ(100, deleted_keys_[0]);
ASSERT_EQ(101, deleted_values_[0]);
}
TEST_P(CacheTest, InsertSameKey) {
Insert(1, 1);
Insert(1, 2);
ASSERT_EQ(2, Lookup(1));
}
TEST_P(CacheTest, Erase) {
Erase(200);
ASSERT_EQ(0U, deleted_keys_.size());
Insert(100, 101);
Insert(200, 201);
Erase(100);
ASSERT_EQ(-1, Lookup(100));
ASSERT_EQ(201, Lookup(200));
ASSERT_EQ(1U, 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(1U, deleted_keys_.size());
}
TEST_P(CacheTest, EntriesArePinned) {
Insert(100, 101);
Cache::Handle* h1 = cache_->Lookup(EncodeKey(100));
ASSERT_EQ(101, DecodeValue(cache_->Value(h1)));
ASSERT_EQ(1U, cache_->GetUsage());
Insert(100, 102);
Cache::Handle* h2 = cache_->Lookup(EncodeKey(100));
ASSERT_EQ(102, DecodeValue(cache_->Value(h2)));
ASSERT_EQ(0U, deleted_keys_.size());
ASSERT_EQ(2U, cache_->GetUsage());
cache_->Release(h1);
ASSERT_EQ(1U, deleted_keys_.size());
ASSERT_EQ(100, deleted_keys_[0]);
ASSERT_EQ(101, deleted_values_[0]);
ASSERT_EQ(1U, cache_->GetUsage());
Erase(100);
ASSERT_EQ(-1, Lookup(100));
ASSERT_EQ(1U, deleted_keys_.size());
ASSERT_EQ(1U, cache_->GetUsage());
cache_->Release(h2);
ASSERT_EQ(2U, deleted_keys_.size());
ASSERT_EQ(100, deleted_keys_[1]);
ASSERT_EQ(102, deleted_values_[1]);
ASSERT_EQ(0U, cache_->GetUsage());
}
TEST_P(CacheTest, EvictionPolicy) {
Insert(100, 101);
Insert(200, 201);
// Frequently used entry must be kept around
for (int i = 0; i < kCacheSize + 100; i++) {
Insert(1000+i, 2000+i);
ASSERT_EQ(101, Lookup(100));
}
ASSERT_EQ(101, Lookup(100));
ASSERT_EQ(-1, Lookup(200));
}
TEST_P(CacheTest, EvictionPolicyRef) {
Insert(100, 101);
Insert(101, 102);
Insert(102, 103);
Insert(103, 104);
Insert(200, 101);
Insert(201, 102);
Insert(202, 103);
Insert(203, 104);
Cache::Handle* h201 = cache_->Lookup(EncodeKey(200));
Cache::Handle* h202 = cache_->Lookup(EncodeKey(201));
Cache::Handle* h203 = cache_->Lookup(EncodeKey(202));
Cache::Handle* h204 = cache_->Lookup(EncodeKey(203));
Insert(300, 101);
Insert(301, 102);
Insert(302, 103);
Insert(303, 104);
// Insert entries much more than Cache capacity
for (int i = 0; i < kCacheSize + 100; i++) {
Insert(1000 + i, 2000 + i);
}
// Check whether the entries inserted in the beginning
// are evicted. Ones without extra ref are evicted and
// those with are not.
ASSERT_EQ(-1, Lookup(100));
ASSERT_EQ(-1, Lookup(101));
ASSERT_EQ(-1, Lookup(102));
ASSERT_EQ(-1, Lookup(103));
ASSERT_EQ(-1, Lookup(300));
ASSERT_EQ(-1, Lookup(301));
ASSERT_EQ(-1, Lookup(302));
ASSERT_EQ(-1, Lookup(303));
ASSERT_EQ(101, Lookup(200));
ASSERT_EQ(102, Lookup(201));
ASSERT_EQ(103, Lookup(202));
ASSERT_EQ(104, Lookup(203));
// Cleaning up all the handles
cache_->Release(h201);
cache_->Release(h202);
cache_->Release(h203);
cache_->Release(h204);
}
TEST_P(CacheTest, EvictEmptyCache) {
// Insert item large than capacity to trigger eviction on empty cache.
auto cache = GetNewCache()(1, 0, false);
ASSERT_OK(cache->Insert("foo", nullptr, 10, dumbDeleter));
}
TEST_P(CacheTest, EraseFromDeleter) {
// Have deleter which will erase item from cache, which will re-enter
// the cache at that point.
std::shared_ptr<Cache> cache = GetNewCache()(10, 0, false);
ASSERT_OK(cache->Insert("foo", nullptr, 1, dumbDeleter));
ASSERT_OK(cache->Insert("bar", cache.get(), 1, eraseDeleter));
cache->Erase("bar");
ASSERT_EQ(nullptr, cache->Lookup("foo"));
ASSERT_EQ(nullptr, cache->Lookup("bar"));
}
TEST_P(CacheTest, ErasedHandleState) {
// insert a key and get two handles
Insert(100, 1000);
Cache::Handle* h1 = cache_->Lookup(EncodeKey(100));
Cache::Handle* h2 = cache_->Lookup(EncodeKey(100));
ASSERT_EQ(h1, h2);
ASSERT_EQ(DecodeValue(cache_->Value(h1)), 1000);
ASSERT_EQ(DecodeValue(cache_->Value(h2)), 1000);
// delete the key from the cache
Erase(100);
// can no longer find in the cache
ASSERT_EQ(-1, Lookup(100));
// release one handle
cache_->Release(h1);
// still can't find in cache
ASSERT_EQ(-1, Lookup(100));
cache_->Release(h2);
}
TEST_P(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_P(CacheTest, NewId) {
uint64_t a = cache_->NewId();
uint64_t b = cache_->NewId();
ASSERT_NE(a, b);
}
class Value {
public:
explicit Value(size_t v) : v_(v) { }
size_t v_;
};
namespace {
void deleter(const Slice& key, void* value) {
delete static_cast<Value *>(value);
}
} // namespace
TEST_P(CacheTest, SetCapacity) {
// test1: increase capacity
// lets create a cache with capacity 5,
// then, insert 5 elements, then increase capacity
// to 10, returned capacity should be 10, usage=5
std::shared_ptr<Cache> cache = GetNewCache()(5, 0, false);
std::vector<Cache::Handle*> handles(10);
// Insert 5 entries, but not releasing.
for (size_t i = 0; i < 5; i++) {
std::string key = ToString(i+1);
Status s = cache->Insert(key, new Value(i + 1), 1, &deleter, &handles[i]);
ASSERT_TRUE(s.ok());
}
ASSERT_EQ(5U, cache->GetCapacity());
ASSERT_EQ(5U, cache->GetUsage());
cache->SetCapacity(10);
ASSERT_EQ(10U, cache->GetCapacity());
ASSERT_EQ(5U, cache->GetUsage());
// test2: decrease capacity
// insert 5 more elements to cache, then release 5,
// then decrease capacity to 7, final capacity should be 7
// and usage should be 7
for (size_t i = 5; i < 10; i++) {
std::string key = ToString(i+1);
Status s = cache->Insert(key, new Value(i + 1), 1, &deleter, &handles[i]);
ASSERT_TRUE(s.ok());
}
ASSERT_EQ(10U, cache->GetCapacity());
ASSERT_EQ(10U, cache->GetUsage());
for (size_t i = 0; i < 5; i++) {
cache->Release(handles[i]);
}
ASSERT_EQ(10U, cache->GetCapacity());
ASSERT_EQ(10U, cache->GetUsage());
cache->SetCapacity(7);
ASSERT_EQ(7, cache->GetCapacity());
ASSERT_EQ(7, cache->GetUsage());
// release remaining 5 to keep valgrind happy
for (size_t i = 5; i < 10; i++) {
cache->Release(handles[i]);
}
}
TEST_P(CacheTest, SetStrictCapacityLimit) {
// test1: set the flag to false. Insert more keys than capacity. See if they
// all go through.
std::shared_ptr<Cache> cache = NewLRUCache(5, 0, false);
std::vector<Cache::Handle*> handles(10);
Status s;
for (size_t i = 0; i < 10; i++) {
std::string key = ToString(i + 1);
s = cache->Insert(key, new Value(i + 1), 1, &deleter, &handles[i]);
ASSERT_OK(s);
ASSERT_NE(nullptr, handles[i]);
}
// test2: set the flag to true. Insert and check if it fails.
std::string extra_key = "extra";
Value* extra_value = new Value(0);
cache->SetStrictCapacityLimit(true);
Cache::Handle* handle;
s = cache->Insert(extra_key, extra_value, 1, &deleter, &handle);
ASSERT_TRUE(s.IsIncomplete());
ASSERT_EQ(nullptr, handle);
for (size_t i = 0; i < 10; i++) {
cache->Release(handles[i]);
}
// test3: init with flag being true.
std::shared_ptr<Cache> cache2 = NewLRUCache(5, 0, true);
for (size_t i = 0; i < 5; i++) {
std::string key = ToString(i + 1);
s = cache2->Insert(key, new Value(i + 1), 1, &deleter, &handles[i]);
ASSERT_OK(s);
ASSERT_NE(nullptr, handles[i]);
}
s = cache2->Insert(extra_key, extra_value, 1, &deleter, &handle);
ASSERT_TRUE(s.IsIncomplete());
ASSERT_EQ(nullptr, handle);
// test insert without handle
s = cache2->Insert(extra_key, extra_value, 1, &deleter);
// AS if the key have been inserted into cache but get evicted immediately.
ASSERT_OK(s);
ASSERT_EQ(5, cache->GetUsage());
ASSERT_EQ(nullptr, cache2->Lookup(extra_key));
for (size_t i = 0; i < 5; i++) {
cache2->Release(handles[i]);
}
}
TEST_P(CacheTest, OverCapacity) {
size_t n = 10;
// a LRUCache with n entries and one shard only
std::shared_ptr<Cache> cache = GetNewCache()(n, 0, false);
std::vector<Cache::Handle*> handles(n+1);
// Insert n+1 entries, but not releasing.
for (size_t i = 0; i < n + 1; i++) {
std::string key = ToString(i+1);
Status s = cache->Insert(key, new Value(i + 1), 1, &deleter, &handles[i]);
ASSERT_TRUE(s.ok());
}
// Guess what's in the cache now?
for (size_t i = 0; i < n + 1; i++) {
std::string key = ToString(i+1);
auto h = cache->Lookup(key);
ASSERT_TRUE(h != nullptr);
if (h) cache->Release(h);
}
// the cache is over capacity since nothing could be evicted
ASSERT_EQ(n + 1U, cache->GetUsage());
for (size_t i = 0; i < n + 1; i++) {
cache->Release(handles[i]);
}
// Make sure eviction is triggered.
cache->SetCapacity(n);
// cache is under capacity now since elements were released
ASSERT_EQ(n, cache->GetUsage());
// element 0 is evicted and the rest is there
// This is consistent with the LRU policy since the element 0
// was released first
for (size_t i = 0; i < n + 1; i++) {
std::string key = ToString(i+1);
auto h = cache->Lookup(key);
if (h) {
ASSERT_NE(i, 0U);
cache->Release(h);
} else {
ASSERT_EQ(i, 0U);
}
}
}
namespace {
std::vector<std::pair<int, int>> callback_state;
void callback(void* entry, size_t charge) {
callback_state.push_back({DecodeValue(entry), static_cast<int>(charge)});
}
};
TEST_P(CacheTest, ApplyToAllCacheEntiresTest) {
std::vector<std::pair<int, int>> inserted;
callback_state.clear();
for (int i = 0; i < 10; ++i) {
Insert(i, i * 2, i + 1);
inserted.push_back({i * 2, i + 1});
}
cache_->ApplyToAllCacheEntries(callback, true);
std::sort(inserted.begin(), inserted.end());
std::sort(callback_state.begin(), callback_state.end());
ASSERT_TRUE(inserted == callback_state);
}
shared_ptr<Cache> NewLRUCacheFunc(size_t capacity, int num_shard_bits,
bool strict_capacity_limit) {
return NewLRUCache(capacity, num_shard_bits, strict_capacity_limit);
}
shared_ptr<Cache> (*new_lru_cache_func)(size_t, int, bool) = NewLRUCacheFunc;
#ifdef SUPPORT_CLOCK_CACHE
shared_ptr<Cache> (*new_clock_cache_func)(size_t, int, bool) = NewClockCache;
INSTANTIATE_TEST_CASE_P(CacheTestInstance, CacheTest,
testing::Values(NewCache(new_lru_cache_func),
NewCache(new_clock_cache_func)));
#else
INSTANTIATE_TEST_CASE_P(CacheTestInstance, CacheTest,
testing::Values(NewCache(new_lru_cache_func)));
#endif // SUPPORT_CLOCK_CACHE
} // namespace rocksdb
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}