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34a70859bc
rocksdb/table/cuckoo_table_reader_test.cc
Maysam Yabandeh 11526252cc Pinnableslice (2nd attempt) 
Summary:
PinnableSlice

    Summary:
    Currently the point lookup values are copied to a string provided by the
    user. This incures an extra memcpy cost. This patch allows doing point lookup
    via a PinnableSlice which pins the source memory location (instead of
    copying their content) and releases them after the content is consumed
    by the user. The old API of Get(string) is translated to the new API
    underneath.

    Here is the summary for improvements:

    value 100 byte: 1.8% regular, 1.2% merge values
    value 1k byte: 11.5% regular, 7.5% merge values
    value 10k byte: 26% regular, 29.9% merge values
    The improvement for merge could be more if we extend this approach to
    pin the merge output and delay the full merge operation until the user
    actually needs it. We have put that for future work.

    PS:
    Sometimes we observe a small decrease in performance when switching from
    t5452014 to this patch but with the old Get(string) API. The d
Closes https://github.com/facebook/rocksdb/pull/1756

Differential Revision: D4391738

Pulled By: maysamyabandeh

fbshipit-source-id: 6f3edd3
2017-03-13 11:54:10 -07:00

563 lines
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// 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.
#ifndef ROCKSDB_LITE
#ifndef GFLAGS
#include <cstdio>
int main() {
fprintf(stderr, "Please install gflags to run this test... Skipping...\n");
return 0;
}
#else
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <gflags/gflags.h>
#include <vector>
#include <string>
#include <map>
#include "table/meta_blocks.h"
#include "table/cuckoo_table_builder.h"
#include "table/cuckoo_table_reader.h"
#include "table/cuckoo_table_factory.h"
#include "table/get_context.h"
#include "util/arena.h"
#include "util/random.h"
#include "util/string_util.h"
#include "util/testharness.h"
#include "util/testutil.h"
using GFLAGS::ParseCommandLineFlags;
using GFLAGS::SetUsageMessage;
DEFINE_string(file_dir, "", "Directory where the files will be created"
" for benchmark. Added for using tmpfs.");
DEFINE_bool(enable_perf, false, "Run Benchmark Tests too.");
DEFINE_bool(write, false,
"Should write new values to file in performance tests?");
DEFINE_bool(identity_as_first_hash, true, "use identity as first hash");
namespace rocksdb {
namespace {
const uint32_t kNumHashFunc = 10;
// Methods, variables related to Hash functions.
std::unordered_map<std::string, std::vector<uint64_t>> hash_map;
void AddHashLookups(const std::string& s, uint64_t bucket_id,
uint32_t num_hash_fun) {
std::vector<uint64_t> v;
for (uint32_t i = 0; i < num_hash_fun; i++) {
v.push_back(bucket_id + i);
}
hash_map[s] = v;
}
uint64_t GetSliceHash(const Slice& s, uint32_t index,
uint64_t max_num_buckets) {
return hash_map[s.ToString()][index];
}
} // namespace
class CuckooReaderTest : public testing::Test {
public:
using testing::Test::SetUp;
CuckooReaderTest() {
options.allow_mmap_reads = true;
env = options.env;
env_options = EnvOptions(options);
}
void SetUp(int num) {
num_items = num;
hash_map.clear();
keys.clear();
keys.resize(num_items);
user_keys.clear();
user_keys.resize(num_items);
values.clear();
values.resize(num_items);
}
std::string NumToStr(int64_t i) {
return std::string(reinterpret_cast<char*>(&i), sizeof(i));
}
void CreateCuckooFileAndCheckReader(
const Comparator* ucomp = BytewiseComparator()) {
std::unique_ptr<WritableFile> writable_file;
ASSERT_OK(env->NewWritableFile(fname, &writable_file, env_options));
unique_ptr<WritableFileWriter> file_writer(
new WritableFileWriter(std::move(writable_file), env_options));
CuckooTableBuilder builder(
file_writer.get(), 0.9, kNumHashFunc, 100, ucomp, 2, false, false,
GetSliceHash, 0 /* column_family_id */, kDefaultColumnFamilyName);
ASSERT_OK(builder.status());
for (uint32_t key_idx = 0; key_idx < num_items; ++key_idx) {
builder.Add(Slice(keys[key_idx]), Slice(values[key_idx]));
ASSERT_OK(builder.status());
ASSERT_EQ(builder.NumEntries(), key_idx + 1);
}
ASSERT_OK(builder.Finish());
ASSERT_EQ(num_items, builder.NumEntries());
file_size = builder.FileSize();
ASSERT_OK(file_writer->Close());
// Check reader now.
std::unique_ptr<RandomAccessFile> read_file;
ASSERT_OK(env->NewRandomAccessFile(fname, &read_file, env_options));
unique_ptr<RandomAccessFileReader> file_reader(
new RandomAccessFileReader(std::move(read_file)));
const ImmutableCFOptions ioptions(options);
CuckooTableReader reader(ioptions, std::move(file_reader), file_size, ucomp,
GetSliceHash);
ASSERT_OK(reader.status());
// Assume no merge/deletion
for (uint32_t i = 0; i < num_items; ++i) {
PinnableSlice value;
GetContext get_context(ucomp, nullptr, nullptr, nullptr,
GetContext::kNotFound, Slice(user_keys[i]), &value,
nullptr, nullptr, nullptr, nullptr);
ASSERT_OK(reader.Get(ReadOptions(), Slice(keys[i]), &get_context));
ASSERT_STREQ(values[i].c_str(), value.data());
}
}
void UpdateKeys(bool with_zero_seqno) {
for (uint32_t i = 0; i < num_items; i++) {
ParsedInternalKey ikey(user_keys[i],
with_zero_seqno ? 0 : i + 1000, kTypeValue);
keys[i].clear();
AppendInternalKey(&keys[i], ikey);
}
}
void CheckIterator(const Comparator* ucomp = BytewiseComparator()) {
std::unique_ptr<RandomAccessFile> read_file;
ASSERT_OK(env->NewRandomAccessFile(fname, &read_file, env_options));
unique_ptr<RandomAccessFileReader> file_reader(
new RandomAccessFileReader(std::move(read_file)));
const ImmutableCFOptions ioptions(options);
CuckooTableReader reader(ioptions, std::move(file_reader), file_size, ucomp,
GetSliceHash);
ASSERT_OK(reader.status());
InternalIterator* it = reader.NewIterator(ReadOptions(), nullptr);
ASSERT_OK(it->status());
ASSERT_TRUE(!it->Valid());
it->SeekToFirst();
int cnt = 0;
while (it->Valid()) {
ASSERT_OK(it->status());
ASSERT_TRUE(Slice(keys[cnt]) == it->key());
ASSERT_TRUE(Slice(values[cnt]) == it->value());
++cnt;
it->Next();
}
ASSERT_EQ(static_cast<uint32_t>(cnt), num_items);
it->SeekToLast();
cnt = static_cast<int>(num_items) - 1;
ASSERT_TRUE(it->Valid());
while (it->Valid()) {
ASSERT_OK(it->status());
ASSERT_TRUE(Slice(keys[cnt]) == it->key());
ASSERT_TRUE(Slice(values[cnt]) == it->value());
--cnt;
it->Prev();
}
ASSERT_EQ(cnt, -1);
cnt = static_cast<int>(num_items) / 2;
it->Seek(keys[cnt]);
while (it->Valid()) {
ASSERT_OK(it->status());
ASSERT_TRUE(Slice(keys[cnt]) == it->key());
ASSERT_TRUE(Slice(values[cnt]) == it->value());
++cnt;
it->Next();
}
ASSERT_EQ(static_cast<uint32_t>(cnt), num_items);
delete it;
Arena arena;
it = reader.NewIterator(ReadOptions(), &arena);
ASSERT_OK(it->status());
ASSERT_TRUE(!it->Valid());
it->Seek(keys[num_items/2]);
ASSERT_TRUE(it->Valid());
ASSERT_OK(it->status());
ASSERT_TRUE(keys[num_items/2] == it->key());
ASSERT_TRUE(values[num_items/2] == it->value());
ASSERT_OK(it->status());
it->~InternalIterator();
}
std::vector<std::string> keys;
std::vector<std::string> user_keys;
std::vector<std::string> values;
uint64_t num_items;
std::string fname;
uint64_t file_size;
Options options;
Env* env;
EnvOptions env_options;
};
TEST_F(CuckooReaderTest, WhenKeyExists) {
SetUp(kNumHashFunc);
fname = test::TmpDir() + "/CuckooReader_WhenKeyExists";
for (uint64_t i = 0; i < num_items; i++) {
user_keys[i] = "key" + NumToStr(i);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + NumToStr(i);
// Give disjoint hash values.
AddHashLookups(user_keys[i], i, kNumHashFunc);
}
CreateCuckooFileAndCheckReader();
// Last level file.
UpdateKeys(true);
CreateCuckooFileAndCheckReader();
// Test with collision. Make all hash values collide.
hash_map.clear();
for (uint32_t i = 0; i < num_items; i++) {
AddHashLookups(user_keys[i], 0, kNumHashFunc);
}
UpdateKeys(false);
CreateCuckooFileAndCheckReader();
// Last level file.
UpdateKeys(true);
CreateCuckooFileAndCheckReader();
}
TEST_F(CuckooReaderTest, WhenKeyExistsWithUint64Comparator) {
SetUp(kNumHashFunc);
fname = test::TmpDir() + "/CuckooReaderUint64_WhenKeyExists";
for (uint64_t i = 0; i < num_items; i++) {
user_keys[i].resize(8);
memcpy(&user_keys[i][0], static_cast<void*>(&i), 8);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + NumToStr(i);
// Give disjoint hash values.
AddHashLookups(user_keys[i], i, kNumHashFunc);
}
CreateCuckooFileAndCheckReader(test::Uint64Comparator());
// Last level file.
UpdateKeys(true);
CreateCuckooFileAndCheckReader(test::Uint64Comparator());
// Test with collision. Make all hash values collide.
hash_map.clear();
for (uint32_t i = 0; i < num_items; i++) {
AddHashLookups(user_keys[i], 0, kNumHashFunc);
}
UpdateKeys(false);
CreateCuckooFileAndCheckReader(test::Uint64Comparator());
// Last level file.
UpdateKeys(true);
CreateCuckooFileAndCheckReader(test::Uint64Comparator());
}
TEST_F(CuckooReaderTest, CheckIterator) {
SetUp(2*kNumHashFunc);
fname = test::TmpDir() + "/CuckooReader_CheckIterator";
for (uint64_t i = 0; i < num_items; i++) {
user_keys[i] = "key" + NumToStr(i);
ParsedInternalKey ikey(user_keys[i], 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + NumToStr(i);
// Give disjoint hash values, in reverse order.
AddHashLookups(user_keys[i], num_items-i-1, kNumHashFunc);
}
CreateCuckooFileAndCheckReader();
CheckIterator();
// Last level file.
UpdateKeys(true);
CreateCuckooFileAndCheckReader();
CheckIterator();
}
TEST_F(CuckooReaderTest, CheckIteratorUint64) {
SetUp(2*kNumHashFunc);
fname = test::TmpDir() + "/CuckooReader_CheckIterator";
for (uint64_t i = 0; i < num_items; i++) {
user_keys[i].resize(8);
memcpy(&user_keys[i][0], static_cast<void*>(&i), 8);
ParsedInternalKey ikey(user_keys[i], 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + NumToStr(i);
// Give disjoint hash values, in reverse order.
AddHashLookups(user_keys[i], num_items-i-1, kNumHashFunc);
}
CreateCuckooFileAndCheckReader(test::Uint64Comparator());
CheckIterator(test::Uint64Comparator());
// Last level file.
UpdateKeys(true);
CreateCuckooFileAndCheckReader(test::Uint64Comparator());
CheckIterator(test::Uint64Comparator());
}
TEST_F(CuckooReaderTest, WhenKeyNotFound) {
// Add keys with colliding hash values.
SetUp(kNumHashFunc);
fname = test::TmpDir() + "/CuckooReader_WhenKeyNotFound";
for (uint64_t i = 0; i < num_items; i++) {
user_keys[i] = "key" + NumToStr(i);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + NumToStr(i);
// Make all hash values collide.
AddHashLookups(user_keys[i], 0, kNumHashFunc);
}
auto* ucmp = BytewiseComparator();
CreateCuckooFileAndCheckReader();
std::unique_ptr<RandomAccessFile> read_file;
ASSERT_OK(env->NewRandomAccessFile(fname, &read_file, env_options));
unique_ptr<RandomAccessFileReader> file_reader(
new RandomAccessFileReader(std::move(read_file)));
const ImmutableCFOptions ioptions(options);
CuckooTableReader reader(ioptions, std::move(file_reader), file_size, ucmp,
GetSliceHash);
ASSERT_OK(reader.status());
// Search for a key with colliding hash values.
std::string not_found_user_key = "key" + NumToStr(num_items);
std::string not_found_key;
AddHashLookups(not_found_user_key, 0, kNumHashFunc);
ParsedInternalKey ikey(not_found_user_key, 1000, kTypeValue);
AppendInternalKey(&not_found_key, ikey);
PinnableSlice value;
GetContext get_context(ucmp, nullptr, nullptr, nullptr, GetContext::kNotFound,
Slice(not_found_key), &value, nullptr, nullptr,
nullptr, nullptr);
ASSERT_OK(reader.Get(ReadOptions(), Slice(not_found_key), &get_context));
ASSERT_TRUE(value.empty());
ASSERT_OK(reader.status());
// Search for a key with an independent hash value.
std::string not_found_user_key2 = "key" + NumToStr(num_items + 1);
AddHashLookups(not_found_user_key2, kNumHashFunc, kNumHashFunc);
ParsedInternalKey ikey2(not_found_user_key2, 1000, kTypeValue);
std::string not_found_key2;
AppendInternalKey(&not_found_key2, ikey2);
value.Reset();
GetContext get_context2(ucmp, nullptr, nullptr, nullptr,
GetContext::kNotFound, Slice(not_found_key2), &value,
nullptr, nullptr, nullptr, nullptr);
ASSERT_OK(reader.Get(ReadOptions(), Slice(not_found_key2), &get_context2));
ASSERT_TRUE(value.empty());
ASSERT_OK(reader.status());
// Test read when key is unused key.
std::string unused_key =
reader.GetTableProperties()->user_collected_properties.at(
CuckooTablePropertyNames::kEmptyKey);
// Add hash values that map to empty buckets.
AddHashLookups(ExtractUserKey(unused_key).ToString(),
kNumHashFunc, kNumHashFunc);
value.Reset();
GetContext get_context3(ucmp, nullptr, nullptr, nullptr,
GetContext::kNotFound, Slice(unused_key), &value,
nullptr, nullptr, nullptr, nullptr);
ASSERT_OK(reader.Get(ReadOptions(), Slice(unused_key), &get_context3));
ASSERT_TRUE(value.empty());
ASSERT_OK(reader.status());
}
// Performance tests
namespace {
void GetKeys(uint64_t num, std::vector<std::string>* keys) {
keys->clear();
IterKey k;
k.SetInternalKey("", 0, kTypeValue);
std::string internal_key_suffix = k.GetKey().ToString();
ASSERT_EQ(static_cast<size_t>(8), internal_key_suffix.size());
for (uint64_t key_idx = 0; key_idx < num; ++key_idx) {
uint64_t value = 2 * key_idx;
std::string new_key(reinterpret_cast<char*>(&value), sizeof(value));
new_key += internal_key_suffix;
keys->push_back(new_key);
}
}
std::string GetFileName(uint64_t num) {
if (FLAGS_file_dir.empty()) {
FLAGS_file_dir = test::TmpDir();
}
return FLAGS_file_dir + "/cuckoo_read_benchmark" +
ToString(num/1000000) + "Mkeys";
}
// Create last level file as we are interested in measuring performance of
// last level file only.
void WriteFile(const std::vector<std::string>& keys,
const uint64_t num, double hash_ratio) {
Options options;
options.allow_mmap_reads = true;
Env* env = options.env;
EnvOptions env_options = EnvOptions(options);
std::string fname = GetFileName(num);
std::unique_ptr<WritableFile> writable_file;
ASSERT_OK(env->NewWritableFile(fname, &writable_file, env_options));
unique_ptr<WritableFileWriter> file_writer(
new WritableFileWriter(std::move(writable_file), env_options));
CuckooTableBuilder builder(
file_writer.get(), hash_ratio, 64, 1000, test::Uint64Comparator(), 5,
false, FLAGS_identity_as_first_hash, nullptr, 0 /* column_family_id */,
kDefaultColumnFamilyName);
ASSERT_OK(builder.status());
for (uint64_t key_idx = 0; key_idx < num; ++key_idx) {
// Value is just a part of key.
builder.Add(Slice(keys[key_idx]), Slice(&keys[key_idx][0], 4));
ASSERT_EQ(builder.NumEntries(), key_idx + 1);
ASSERT_OK(builder.status());
}
ASSERT_OK(builder.Finish());
ASSERT_EQ(num, builder.NumEntries());
ASSERT_OK(file_writer->Close());
uint64_t file_size;
env->GetFileSize(fname, &file_size);
std::unique_ptr<RandomAccessFile> read_file;
ASSERT_OK(env->NewRandomAccessFile(fname, &read_file, env_options));
unique_ptr<RandomAccessFileReader> file_reader(
new RandomAccessFileReader(std::move(read_file)));
const ImmutableCFOptions ioptions(options);
CuckooTableReader reader(ioptions, std::move(file_reader), file_size,
test::Uint64Comparator(), nullptr);
ASSERT_OK(reader.status());
ReadOptions r_options;
PinnableSlice value;
// Assume only the fast path is triggered
GetContext get_context(nullptr, nullptr, nullptr, nullptr,
GetContext::kNotFound, Slice(), &value, nullptr,
nullptr, nullptr, nullptr);
for (uint64_t i = 0; i < num; ++i) {
value.Reset();
value.clear();
ASSERT_OK(reader.Get(r_options, Slice(keys[i]), &get_context));
ASSERT_TRUE(Slice(keys[i]) == Slice(&keys[i][0], 4));
}
}
void ReadKeys(uint64_t num, uint32_t batch_size) {
Options options;
options.allow_mmap_reads = true;
Env* env = options.env;
EnvOptions env_options = EnvOptions(options);
std::string fname = GetFileName(num);
uint64_t file_size;
env->GetFileSize(fname, &file_size);
std::unique_ptr<RandomAccessFile> read_file;
ASSERT_OK(env->NewRandomAccessFile(fname, &read_file, env_options));
unique_ptr<RandomAccessFileReader> file_reader(
new RandomAccessFileReader(std::move(read_file)));
const ImmutableCFOptions ioptions(options);
CuckooTableReader reader(ioptions, std::move(file_reader), file_size,
test::Uint64Comparator(), nullptr);
ASSERT_OK(reader.status());
const UserCollectedProperties user_props =
reader.GetTableProperties()->user_collected_properties;
const uint32_t num_hash_fun = *reinterpret_cast<const uint32_t*>(
user_props.at(CuckooTablePropertyNames::kNumHashFunc).data());
const uint64_t table_size = *reinterpret_cast<const uint64_t*>(
user_props.at(CuckooTablePropertyNames::kHashTableSize).data());
fprintf(stderr, "With %" PRIu64 " items, utilization is %.2f%%, number of"
" hash functions: %u.\n", num, num * 100.0 / (table_size), num_hash_fun);
ReadOptions r_options;
std::vector<uint64_t> keys;
keys.reserve(num);
for (uint64_t i = 0; i < num; ++i) {
keys.push_back(2 * i);
}
std::random_shuffle(keys.begin(), keys.end());
PinnableSlice value;
// Assume only the fast path is triggered
GetContext get_context(nullptr, nullptr, nullptr, nullptr,
GetContext::kNotFound, Slice(), &value, nullptr,
nullptr, nullptr, nullptr);
uint64_t start_time = env->NowMicros();
if (batch_size > 0) {
for (uint64_t i = 0; i < num; i += batch_size) {
for (uint64_t j = i; j < i+batch_size && j < num; ++j) {
reader.Prepare(Slice(reinterpret_cast<char*>(&keys[j]), 16));
}
for (uint64_t j = i; j < i+batch_size && j < num; ++j) {
reader.Get(r_options, Slice(reinterpret_cast<char*>(&keys[j]), 16),
&get_context);
}
}
} else {
for (uint64_t i = 0; i < num; i++) {
reader.Get(r_options, Slice(reinterpret_cast<char*>(&keys[i]), 16),
&get_context);
}
}
float time_per_op = (env->NowMicros() - start_time) * 1.0f / num;
fprintf(stderr,
"Time taken per op is %.3fus (%.1f Mqps) with batch size of %u\n",
time_per_op, 1.0 / time_per_op, batch_size);
}
} // namespace.
TEST_F(CuckooReaderTest, TestReadPerformance) {
if (!FLAGS_enable_perf) {
return;
}
double hash_ratio = 0.95;
// These numbers are chosen to have a hash utilizaiton % close to
// 0.9, 0.75, 0.6 and 0.5 respectively.
// They all create 128 M buckets.
std::vector<uint64_t> nums = {120*1024*1024, 100*1024*1024, 80*1024*1024,
70*1024*1024};
#ifndef NDEBUG
fprintf(stdout,
"WARNING: Not compiled with DNDEBUG. Performance tests may be slow.\n");
#endif
for (uint64_t num : nums) {
if (FLAGS_write ||
Env::Default()->FileExists(GetFileName(num)).IsNotFound()) {
std::vector<std::string> all_keys;
GetKeys(num, &all_keys);
WriteFile(all_keys, num, hash_ratio);
}
ReadKeys(num, 0);
ReadKeys(num, 10);
ReadKeys(num, 25);
ReadKeys(num, 50);
ReadKeys(num, 100);
fprintf(stderr, "\n");
}
}
} // namespace rocksdb
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
ParseCommandLineFlags(&argc, &argv, true);
return RUN_ALL_TESTS();
}
#endif // GFLAGS.
#else
#include <stdio.h>
int main(int argc, char** argv) {
fprintf(stderr, "SKIPPED as Cuckoo table is not supported in ROCKSDB_LITE\n");
return 0;
}
#endif // ROCKSDB_LITE
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