andreacavalli/rocksdb
0
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
1dfc5eaab0
rocksdb/utilities/simulator_cache/cache_simulator_test.cc
haoyuhuang e648c1d9eb Cache simulator: Optimize hybrid row-block cache. (#5616) 
Summary:
This PR optimizes the hybrid row-block cache simulator. If a Get request hits the cache, we treat all its future accesses as hits.

Consider a Get request (no snapshot) accesses multiple files, e.g, file1, file2, file3. We construct the row key as "fdnumber_key_0". Before this PR, if it hits the cache when searching the key in file1, we continue to process its accesses in file2 and file3 which is unnecessary.

With this PR, if "file1_key_0" is in the cache, we treat all future accesses of this Get request as hits.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5616

Differential Revision: D16453187

Pulled By: HaoyuHuang

fbshipit-source-id: 56f3169cc322322305baaf5543226a0824fae19f
2019-07-29 10:58:15 -07:00

494 lines
20 KiB
C++
Raw Blame History

// 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 "utilities/simulator_cache/cache_simulator.h"
#include <cstdlib>
#include "rocksdb/env.h"
#include "test_util/testharness.h"
#include "test_util/testutil.h"
namespace rocksdb {
namespace {
const std::string kBlockKeyPrefix = "test-block-";
const std::string kRefKeyPrefix = "test-get-";
const std::string kRefKeySequenceNumber = std::string(8, 'c');
const uint64_t kGetId = 1;
const uint64_t kGetBlockId = 100;
const uint64_t kCompactionBlockId = 1000;
const uint64_t kCacheSize = 1024 * 1024 * 1024;
const uint64_t kGhostCacheSize = 1024 * 1024;
} // namespace
class CacheSimulatorTest : public testing::Test {
public:
const size_t kNumBlocks = 5;
const size_t kValueSize = 1000;
CacheSimulatorTest() { env_ = rocksdb::Env::Default(); }
BlockCacheTraceRecord GenerateGetRecord(uint64_t getid) {
BlockCacheTraceRecord record;
record.block_type = TraceType::kBlockTraceDataBlock;
record.block_size = 4096;
record.block_key = kBlockKeyPrefix + std::to_string(kGetBlockId);
record.access_timestamp = env_->NowMicros();
record.cf_id = 0;
record.cf_name = "test";
record.caller = TableReaderCaller::kUserGet;
record.level = 6;
record.sst_fd_number = 0;
record.get_id = getid;
record.is_cache_hit = Boolean::kFalse;
record.no_insert = Boolean::kFalse;
record.referenced_key =
kRefKeyPrefix + std::to_string(kGetId) + kRefKeySequenceNumber;
record.referenced_key_exist_in_block = Boolean::kTrue;
record.referenced_data_size = 100;
record.num_keys_in_block = 300;
return record;
}
BlockCacheTraceRecord GenerateCompactionRecord() {
BlockCacheTraceRecord record;
record.block_type = TraceType::kBlockTraceDataBlock;
record.block_size = 4096;
record.block_key = kBlockKeyPrefix + std::to_string(kCompactionBlockId);
record.access_timestamp = env_->NowMicros();
record.cf_id = 0;
record.cf_name = "test";
record.caller = TableReaderCaller::kCompaction;
record.level = 6;
record.sst_fd_number = kCompactionBlockId;
record.is_cache_hit = Boolean::kFalse;
record.no_insert = Boolean::kTrue;
return record;
}
void AssertCache(std::shared_ptr<Cache> sim_cache,
const MissRatioStats& miss_ratio_stats,
uint64_t expected_usage, uint64_t expected_num_accesses,
uint64_t expected_num_misses,
std::vector<std::string> blocks,
std::vector<std::string> keys) {
EXPECT_EQ(expected_usage, sim_cache->GetUsage());
EXPECT_EQ(expected_num_accesses, miss_ratio_stats.total_accesses());
EXPECT_EQ(expected_num_misses, miss_ratio_stats.total_misses());
for (auto const& block : blocks) {
auto handle = sim_cache->Lookup(block);
EXPECT_NE(nullptr, handle);
sim_cache->Release(handle);
}
for (auto const& key : keys) {
std::string row_key = kRefKeyPrefix + key + kRefKeySequenceNumber;
auto handle =
sim_cache->Lookup("0_" + ExtractUserKey(row_key).ToString() + "_0");
EXPECT_NE(nullptr, handle);
sim_cache->Release(handle);
}
}
Env* env_;
};
TEST_F(CacheSimulatorTest, GhostCache) {
const std::string key1 = "test1";
const std::string key2 = "test2";
std::unique_ptr<GhostCache> ghost_cache(new GhostCache(
NewLRUCache(/*capacity=*/kGhostCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0)));
EXPECT_FALSE(ghost_cache->Admit(key1));
EXPECT_TRUE(ghost_cache->Admit(key1));
EXPECT_TRUE(ghost_cache->Admit(key1));
EXPECT_FALSE(ghost_cache->Admit(key2));
EXPECT_TRUE(ghost_cache->Admit(key2));
}
TEST_F(CacheSimulatorTest, CacheSimulator) {
const BlockCacheTraceRecord& access = GenerateGetRecord(kGetId);
const BlockCacheTraceRecord& compaction_access = GenerateCompactionRecord();
std::shared_ptr<Cache> sim_cache =
NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0);
std::unique_ptr<CacheSimulator> cache_simulator(
new CacheSimulator(nullptr, sim_cache));
cache_simulator->Access(access);
cache_simulator->Access(access);
ASSERT_EQ(2, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(50, cache_simulator->miss_ratio_stats().miss_ratio());
ASSERT_EQ(2, cache_simulator->miss_ratio_stats().user_accesses());
ASSERT_EQ(50, cache_simulator->miss_ratio_stats().user_miss_ratio());
cache_simulator->Access(compaction_access);
cache_simulator->Access(compaction_access);
ASSERT_EQ(4, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(75, cache_simulator->miss_ratio_stats().miss_ratio());
ASSERT_EQ(2, cache_simulator->miss_ratio_stats().user_accesses());
ASSERT_EQ(50, cache_simulator->miss_ratio_stats().user_miss_ratio());
cache_simulator->reset_counter();
ASSERT_EQ(0, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(-1, cache_simulator->miss_ratio_stats().miss_ratio());
auto handle = sim_cache->Lookup(access.block_key);
ASSERT_NE(nullptr, handle);
sim_cache->Release(handle);
handle = sim_cache->Lookup(compaction_access.block_key);
ASSERT_EQ(nullptr, handle);
}
TEST_F(CacheSimulatorTest, GhostCacheSimulator) {
const BlockCacheTraceRecord& access = GenerateGetRecord(kGetId);
std::unique_ptr<GhostCache> ghost_cache(new GhostCache(
NewLRUCache(/*capacity=*/kGhostCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0)));
std::unique_ptr<CacheSimulator> cache_simulator(new CacheSimulator(
std::move(ghost_cache),
NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0)));
cache_simulator->Access(access);
cache_simulator->Access(access);
ASSERT_EQ(2, cache_simulator->miss_ratio_stats().total_accesses());
// Both of them will be miss since we have a ghost cache.
ASSERT_EQ(100, cache_simulator->miss_ratio_stats().miss_ratio());
}
TEST_F(CacheSimulatorTest, PrioritizedCacheSimulator) {
const BlockCacheTraceRecord& access = GenerateGetRecord(kGetId);
std::shared_ptr<Cache> sim_cache =
NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0);
std::unique_ptr<PrioritizedCacheSimulator> cache_simulator(
new PrioritizedCacheSimulator(nullptr, sim_cache));
cache_simulator->Access(access);
cache_simulator->Access(access);
ASSERT_EQ(2, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(50, cache_simulator->miss_ratio_stats().miss_ratio());
auto handle = sim_cache->Lookup(access.block_key);
ASSERT_NE(nullptr, handle);
sim_cache->Release(handle);
}
TEST_F(CacheSimulatorTest, GhostPrioritizedCacheSimulator) {
const BlockCacheTraceRecord& access = GenerateGetRecord(kGetId);
std::unique_ptr<GhostCache> ghost_cache(new GhostCache(
NewLRUCache(/*capacity=*/kGhostCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0)));
std::unique_ptr<PrioritizedCacheSimulator> cache_simulator(
new PrioritizedCacheSimulator(
std::move(ghost_cache),
NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0)));
cache_simulator->Access(access);
cache_simulator->Access(access);
ASSERT_EQ(2, cache_simulator->miss_ratio_stats().total_accesses());
// Both of them will be miss since we have a ghost cache.
ASSERT_EQ(100, cache_simulator->miss_ratio_stats().miss_ratio());
}
TEST_F(CacheSimulatorTest, HybridRowBlockCacheSimulator) {
uint64_t block_id = 100;
BlockCacheTraceRecord first_get = GenerateGetRecord(kGetId);
first_get.get_from_user_specified_snapshot = Boolean::kTrue;
BlockCacheTraceRecord second_get = GenerateGetRecord(kGetId + 1);
second_get.referenced_data_size = 0;
second_get.referenced_key_exist_in_block = Boolean::kFalse;
second_get.get_from_user_specified_snapshot = Boolean::kTrue;
BlockCacheTraceRecord third_get = GenerateGetRecord(kGetId + 2);
third_get.referenced_data_size = 0;
third_get.referenced_key_exist_in_block = Boolean::kFalse;
third_get.referenced_key = kRefKeyPrefix + "third_get";
// We didn't find the referenced key in the third get.
third_get.referenced_key_exist_in_block = Boolean::kFalse;
third_get.referenced_data_size = 0;
std::shared_ptr<Cache> sim_cache =
NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0);
std::unique_ptr<HybridRowBlockCacheSimulator> cache_simulator(
new HybridRowBlockCacheSimulator(
nullptr, sim_cache, /*insert_blocks_row_kvpair_misses=*/true));
// The first get request accesses 10 blocks. We should only report 10 accesses
// and 100% miss.
for (uint32_t i = 0; i < 10; i++) {
first_get.block_key = kBlockKeyPrefix + std::to_string(block_id);
cache_simulator->Access(first_get);
block_id++;
}
ASSERT_EQ(10, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(100, cache_simulator->miss_ratio_stats().miss_ratio());
ASSERT_EQ(10, cache_simulator->miss_ratio_stats().user_accesses());
ASSERT_EQ(100, cache_simulator->miss_ratio_stats().user_miss_ratio());
auto handle = sim_cache->Lookup(
std::to_string(first_get.sst_fd_number) + "_" +
ExtractUserKey(first_get.referenced_key).ToString() + "_" +
std::to_string(1 + GetInternalKeySeqno(first_get.referenced_key)));
ASSERT_NE(nullptr, handle);
sim_cache->Release(handle);
for (uint32_t i = 100; i < block_id; i++) {
handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
ASSERT_NE(nullptr, handle);
sim_cache->Release(handle);
}
// The second get request accesses the same key. We should report 15
// access and 66% miss, 10 misses with 15 accesses.
// We do not consider these 5 block lookups as misses since the row hits the
// cache.
for (uint32_t i = 0; i < 5; i++) {
second_get.block_key = kBlockKeyPrefix + std::to_string(block_id);
cache_simulator->Access(second_get);
block_id++;
}
ASSERT_EQ(15, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(66, static_cast<uint64_t>(
cache_simulator->miss_ratio_stats().miss_ratio()));
ASSERT_EQ(15, cache_simulator->miss_ratio_stats().user_accesses());
ASSERT_EQ(66, static_cast<uint64_t>(
cache_simulator->miss_ratio_stats().user_miss_ratio()));
handle = sim_cache->Lookup(
std::to_string(second_get.sst_fd_number) + "_" +
ExtractUserKey(second_get.referenced_key).ToString() + "_" +
std::to_string(1 + GetInternalKeySeqno(second_get.referenced_key)));
ASSERT_NE(nullptr, handle);
sim_cache->Release(handle);
for (uint32_t i = 100; i < block_id; i++) {
handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
if (i < 110) {
ASSERT_NE(nullptr, handle) << i;
sim_cache->Release(handle);
} else {
ASSERT_EQ(nullptr, handle) << i;
}
}
// The third get on a different key and does not have a size.
// This key should not be inserted into the cache.
for (uint32_t i = 0; i < 5; i++) {
third_get.block_key = kBlockKeyPrefix + std::to_string(block_id);
cache_simulator->Access(third_get);
block_id++;
}
ASSERT_EQ(20, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(75, static_cast<uint64_t>(
cache_simulator->miss_ratio_stats().miss_ratio()));
ASSERT_EQ(20, cache_simulator->miss_ratio_stats().user_accesses());
ASSERT_EQ(75, static_cast<uint64_t>(
cache_simulator->miss_ratio_stats().user_miss_ratio()));
// Assert that the third key is not inserted into the cache.
handle = sim_cache->Lookup(std::to_string(third_get.sst_fd_number) + "_" +
third_get.referenced_key);
ASSERT_EQ(nullptr, handle);
for (uint32_t i = 100; i < block_id; i++) {
if (i < 110 || i >= 115) {
handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
ASSERT_NE(nullptr, handle) << i;
sim_cache->Release(handle);
} else {
handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
ASSERT_EQ(nullptr, handle) << i;
}
}
}
TEST_F(CacheSimulatorTest, HybridRowBlockCacheSimulatorGetTest) {
BlockCacheTraceRecord get = GenerateGetRecord(kGetId);
get.block_size = 1;
get.referenced_data_size = 0;
get.access_timestamp = 0;
get.block_key = "1";
get.get_id = 1;
get.get_from_user_specified_snapshot = Boolean::kFalse;
get.referenced_key =
kRefKeyPrefix + std::to_string(1) + kRefKeySequenceNumber;
get.no_insert = Boolean::kFalse;
get.sst_fd_number = 0;
get.get_from_user_specified_snapshot = Boolean::kFalse;
std::shared_ptr<Cache> sim_cache =
NewLRUCache(/*capacity=*/16, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0);
std::unique_ptr<HybridRowBlockCacheSimulator> cache_simulator(
new HybridRowBlockCacheSimulator(
nullptr, sim_cache, /*insert_blocks_row_kvpair_misses=*/true));
// Expect a miss and does not insert the row key-value pair since it does not
// have size.
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 1, 1, 1, {"1"},
{});
get.access_timestamp += 1;
get.referenced_data_size = 1;
get.block_key = "2";
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 3, 2, 2,
{"1", "2"}, {"1"});
get.access_timestamp += 1;
get.block_key = "3";
// K1 should not inserted again.
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 4, 3, 3,
{"1", "2", "3"}, {"1"});
// A second get request referencing the same key.
get.access_timestamp += 1;
get.get_id = 2;
get.block_key = "4";
get.referenced_data_size = 0;
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 4, 4, 3,
{"1", "2", "3"}, {"1"});
// A third get request searches three files, three different keys.
// And the second key observes a hit.
get.access_timestamp += 1;
get.referenced_data_size = 1;
get.get_id = 3;
get.block_key = "3";
get.referenced_key = kRefKeyPrefix + "2" + kRefKeySequenceNumber;
// K2 should observe a miss. Block 3 observes a hit.
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 5, 5, 3,
{"1", "2", "3"}, {"1", "2"});
get.access_timestamp += 1;
get.referenced_data_size = 1;
get.get_id = 3;
get.block_key = "4";
get.referenced_data_size = 1;
get.referenced_key = kRefKeyPrefix + "1" + kRefKeySequenceNumber;
// K1 should observe a hit.
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 5, 6, 3,
{"1", "2", "3"}, {"1", "2"});
get.access_timestamp += 1;
get.referenced_data_size = 1;
get.get_id = 3;
get.block_key = "4";
get.referenced_data_size = 1;
get.referenced_key = kRefKeyPrefix + "3" + kRefKeySequenceNumber;
// K3 should observe a miss.
// However, as the get already complete, we should not access k3 any more.
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 5, 7, 3,
{"1", "2", "3"}, {"1", "2"});
// A fourth get request searches one file and two blocks. One row key.
get.access_timestamp += 1;
get.get_id = 4;
get.block_key = "5";
get.referenced_key = kRefKeyPrefix + "4" + kRefKeySequenceNumber;
get.referenced_data_size = 1;
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 7, 8, 4,
{"1", "2", "3", "5"}, {"1", "2", "4"});
for (auto const& key : {"1", "2", "4"}) {
auto handle = sim_cache->Lookup("0_" + kRefKeyPrefix + key + "_0");
ASSERT_NE(nullptr, handle);
sim_cache->Release(handle);
}
// A bunch of insertions which evict cached row keys.
for (uint32_t i = 6; i < 100; i++) {
get.access_timestamp += 1;
get.get_id = 0;
get.block_key = std::to_string(i);
cache_simulator->Access(get);
}
get.get_id = 4;
// A different block.
get.block_key = "100";
// Same row key and should not be inserted again.
get.referenced_key = kRefKeyPrefix + "4" + kRefKeySequenceNumber;
get.referenced_data_size = 1;
cache_simulator->Access(get);
AssertCache(sim_cache, cache_simulator->miss_ratio_stats(), 16, 103, 99, {},
{});
for (auto const& key : {"1", "2", "4"}) {
auto handle = sim_cache->Lookup("0_" + kRefKeyPrefix + key + "_0");
ASSERT_EQ(nullptr, handle);
}
}
TEST_F(CacheSimulatorTest, HybridRowBlockNoInsertCacheSimulator) {
uint64_t block_id = 100;
BlockCacheTraceRecord first_get = GenerateGetRecord(kGetId);
std::shared_ptr<Cache> sim_cache =
NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0);
std::unique_ptr<HybridRowBlockCacheSimulator> cache_simulator(
new HybridRowBlockCacheSimulator(
nullptr, sim_cache, /*insert_blocks_row_kvpair_misses=*/false));
for (uint32_t i = 0; i < 9; i++) {
first_get.block_key = kBlockKeyPrefix + std::to_string(block_id);
cache_simulator->Access(first_get);
block_id++;
}
auto handle = sim_cache->Lookup(
std::to_string(first_get.sst_fd_number) + "_" +
ExtractUserKey(first_get.referenced_key).ToString() + "_0");
ASSERT_NE(nullptr, handle);
sim_cache->Release(handle);
// All blocks are missing from the cache since insert_blocks_row_kvpair_misses
// is set to false.
for (uint32_t i = 100; i < block_id; i++) {
handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
ASSERT_EQ(nullptr, handle);
}
}
TEST_F(CacheSimulatorTest, GhostHybridRowBlockCacheSimulator) {
std::unique_ptr<GhostCache> ghost_cache(new GhostCache(
NewLRUCache(/*capacity=*/kGhostCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0)));
const BlockCacheTraceRecord& first_get = GenerateGetRecord(kGetId);
const BlockCacheTraceRecord& second_get = GenerateGetRecord(kGetId + 1);
const BlockCacheTraceRecord& third_get = GenerateGetRecord(kGetId + 2);
std::unique_ptr<HybridRowBlockCacheSimulator> cache_simulator(
new HybridRowBlockCacheSimulator(
std::move(ghost_cache),
NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
/*strict_capacity_limit=*/false,
/*high_pri_pool_ratio=*/0),
/*insert_blocks_row_kvpair_misses=*/false));
// Two get requests access the same key.
cache_simulator->Access(first_get);
cache_simulator->Access(second_get);
ASSERT_EQ(2, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(100, cache_simulator->miss_ratio_stats().miss_ratio());
ASSERT_EQ(2, cache_simulator->miss_ratio_stats().user_accesses());
ASSERT_EQ(100, cache_simulator->miss_ratio_stats().user_miss_ratio());
// We insert the key-value pair upon the second get request. A third get
// request should observe a hit.
for (uint32_t i = 0; i < 10; i++) {
cache_simulator->Access(third_get);
}
ASSERT_EQ(12, cache_simulator->miss_ratio_stats().total_accesses());
ASSERT_EQ(16, static_cast<uint64_t>(
cache_simulator->miss_ratio_stats().miss_ratio()));
ASSERT_EQ(12, cache_simulator->miss_ratio_stats().user_accesses());
ASSERT_EQ(16, static_cast<uint64_t>(
cache_simulator->miss_ratio_stats().user_miss_ratio()));
}
} // namespace rocksdb
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
Reference in New Issue View Git Blame Copy Permalink