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rocksdb/table/cuckoo_table_builder_test.cc

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// Copyright (c) 2013, 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.
#include <vector>
#include <string>
#include <map>
#include <utility>
#include "table/meta_blocks.h"
#include "table/cuckoo_table_builder.h"
#include "util/random.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace rocksdb {
extern const uint64_t kCuckooTableMagicNumber;
namespace {
std::unordered_map<std::string, std::vector<unsigned int>> hash_map;
void AddHashLookups(const std::string& s, unsigned int bucket_id,
unsigned int num_hash_fun) {
std::vector<unsigned int> v;
for (unsigned int i = 0; i < num_hash_fun; i++) {
v.push_back(bucket_id + i);
}
hash_map[s] = v;
return;
}
unsigned int GetSliceHash(const Slice& s, unsigned int index,
unsigned int max_num_buckets) {
return hash_map[s.ToString()][index];
}
} // namespace
class CuckooBuilderTest {
public:
CuckooBuilderTest() {
env_ = Env::Default();
}
void CheckFileContents(const std::string& expected_data) {
// Read file
unique_ptr<RandomAccessFile> read_file;
ASSERT_OK(env_->NewRandomAccessFile(fname, &read_file, env_options_));
uint64_t read_file_size;
ASSERT_OK(env_->GetFileSize(fname, &read_file_size));
// Assert Table Properties.
TableProperties* props = nullptr;
ASSERT_OK(ReadTableProperties(read_file.get(), read_file_size,
kCuckooTableMagicNumber, env_, nullptr, &props));
ASSERT_EQ(props->num_entries, num_items);
ASSERT_EQ(props->fixed_key_len, key_length);
// Check unused bucket.
std::string unused_bucket = props->user_collected_properties[
CuckooTablePropertyNames::kEmptyBucket];
ASSERT_EQ(expected_unused_bucket, unused_bucket);
unsigned int max_buckets;
Slice max_buckets_slice = Slice(props->user_collected_properties[
CuckooTablePropertyNames::kMaxNumBuckets]);
GetVarint32(&max_buckets_slice, &max_buckets);
ASSERT_EQ(expected_max_buckets, max_buckets);
delete props;
// Check contents of the bucket.
std::string read_data;
read_data.resize(expected_data.size());
Slice read_slice;
ASSERT_OK(read_file->Read(0, expected_data.size(),
&read_slice, &read_data[0]));
ASSERT_EQ(expected_data, read_data);
}
Env* env_;
const EnvOptions env_options_;
std::string fname;
std::string expected_unused_bucket;
unsigned int file_size = 100000;
unsigned int num_items = 20;
unsigned int num_hash_fun = 64;
double hash_table_ratio = 0.9;
unsigned int ikey_length;
unsigned int user_key_length;
unsigned int key_length;
unsigned int value_length;
unsigned int bucket_length;
unsigned int expected_max_buckets;
};
TEST(CuckooBuilderTest, NoCollision) {
hash_map.clear();
num_items = 20;
num_hash_fun = 64;
std::vector<std::string> user_keys(num_items);
std::vector<std::string> keys(num_items);
std::vector<std::string> values(num_items);
unsigned int bucket_ids = 0;
for (unsigned int i = 0; i < num_items; i++) {
user_keys[i] = "keys" + std::to_string(i+100);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + std::to_string(i+100);
AddHashLookups(user_keys[i], bucket_ids, num_hash_fun);
bucket_ids += num_hash_fun;
}
ikey_length = keys[0].size();
key_length = ikey_length;
value_length = values[0].size();
bucket_length = ikey_length + value_length;
expected_max_buckets = file_size / bucket_length;
std::string expected_unused_user_key = "keys10:";
ParsedInternalKey ikey(expected_unused_user_key, 0, kTypeValue);
AppendInternalKey(&expected_unused_bucket, ikey);
expected_unused_bucket.resize(bucket_length, 'a');
unique_ptr<WritableFile> writable_file;
fname = test::TmpDir() + "/BasicTest_writable_file";
ASSERT_OK(env_->NewWritableFile(fname, &writable_file, env_options_));
CuckooTableBuilder cuckoo_builder(
writable_file.get(), ikey_length,
value_length, hash_table_ratio,
file_size, num_hash_fun, 100, GetSliceHash);
ASSERT_OK(cuckoo_builder.status());
unsigned int key_idx = 0;
std::string expected_file_data = "";
for (unsigned int i = 0; i < expected_max_buckets; i++) {
if (key_idx * num_hash_fun == i && key_idx < num_items) {
cuckoo_builder.Add(Slice(keys[key_idx]), Slice(values[key_idx]));
ASSERT_EQ(cuckoo_builder.NumEntries(), key_idx + 1);
ASSERT_OK(cuckoo_builder.status());
expected_file_data.append(keys[key_idx] + values[key_idx]);
++key_idx;
} else {
expected_file_data.append(expected_unused_bucket);
}
}
ASSERT_OK(cuckoo_builder.Finish());
writable_file->Close();
CheckFileContents(expected_file_data);
}
TEST(CuckooBuilderTest, NoCollisionLastLevel) {
hash_map.clear();
std::vector<std::string> user_keys(num_items);
std::vector<std::string> keys(num_items);
std::vector<std::string> values(num_items);
unsigned int bucket_ids = 0;
for (unsigned int i = 0; i < num_items; i++) {
user_keys[i] = "keys" + std::to_string(i+100);
// Set zero sequence number in all keys.
ParsedInternalKey ikey(user_keys[i], 0, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + std::to_string(i+100);
AddHashLookups(user_keys[i], bucket_ids, num_hash_fun);
bucket_ids += num_hash_fun;
}
ikey_length = keys[0].size();
user_key_length = user_keys[0].size();
key_length = user_key_length;
value_length = values[0].size();
bucket_length = key_length + value_length;
expected_max_buckets = file_size / bucket_length;
expected_unused_bucket = "keys10:";
expected_unused_bucket.resize(bucket_length, 'a');
unique_ptr<WritableFile> writable_file;
fname = test::TmpDir() + "/NoCollisionLastLevel_writable_file";
ASSERT_OK(env_->NewWritableFile(fname, &writable_file, env_options_));
CuckooTableBuilder cuckoo_builder(
writable_file.get(), key_length,
value_length, hash_table_ratio,
file_size, num_hash_fun, 100, GetSliceHash);
ASSERT_OK(cuckoo_builder.status());
unsigned int key_idx = 0;
std::string expected_file_data = "";
for (unsigned int i = 0; i < expected_max_buckets; i++) {
if (key_idx * num_hash_fun == i && key_idx < num_items) {
cuckoo_builder.Add(Slice(keys[key_idx]), Slice(values[key_idx]));
ASSERT_EQ(cuckoo_builder.NumEntries(), key_idx + 1);
ASSERT_OK(cuckoo_builder.status());
expected_file_data.append(user_keys[key_idx] + values[key_idx]);
++key_idx;
} else {
expected_file_data.append(expected_unused_bucket);
}
}
ASSERT_OK(cuckoo_builder.Finish());
writable_file->Close();
CheckFileContents(expected_file_data);
}
TEST(CuckooBuilderTest, WithCollision) {
// Take keys with colliding hash function values.
hash_map.clear();
num_hash_fun = 20;
num_items = num_hash_fun;
std::vector<std::string> user_keys(num_items);
std::vector<std::string> keys(num_items);
std::vector<std::string> values(num_items);
for (unsigned int i = 0; i < num_items; i++) {
user_keys[i] = "keys" + std::to_string(i+100);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + std::to_string(i+100);
// Make all hash values collide.
AddHashLookups(user_keys[i], 0, num_hash_fun);
}
ikey_length = keys[0].size();
value_length = values[0].size();
key_length = ikey_length;
bucket_length = key_length + value_length;
expected_max_buckets = file_size / bucket_length;
std::string expected_unused_user_key = "keys10:";
ParsedInternalKey ikey(expected_unused_user_key, 0, kTypeValue);
AppendInternalKey(&expected_unused_bucket, ikey);
expected_unused_bucket.resize(bucket_length, 'a');
unique_ptr<WritableFile> writable_file;
fname = test::TmpDir() + "/WithCollision_writable_file";
ASSERT_OK(env_->NewWritableFile(fname, &writable_file, env_options_));
CuckooTableBuilder cuckoo_builder(
writable_file.get(), key_length, value_length, hash_table_ratio,
file_size, num_hash_fun, 100, GetSliceHash);
ASSERT_OK(cuckoo_builder.status());
unsigned int key_idx = 0;
std::string expected_file_data = "";
for (unsigned int i = 0; i < expected_max_buckets; i++) {
if (key_idx == i && key_idx < num_items) {
cuckoo_builder.Add(Slice(keys[key_idx]), Slice(values[key_idx]));
ASSERT_EQ(cuckoo_builder.NumEntries(), key_idx + 1);
ASSERT_OK(cuckoo_builder.status());
expected_file_data.append(keys[key_idx] + values[key_idx]);
++key_idx;
} else {
expected_file_data.append(expected_unused_bucket);
}
}
ASSERT_OK(cuckoo_builder.Finish());
writable_file->Close();
CheckFileContents(expected_file_data);
}
TEST(CuckooBuilderTest, FailWithTooManyCollisions) {
// Take keys with colliding hash function values.
// Take more keys than the number of hash functions.
hash_map.clear();
num_hash_fun = 20;
num_items = num_hash_fun + 1;
std::vector<std::string> user_keys(num_items);
std::vector<std::string> keys(num_items);
std::vector<std::string> values(num_items);
for (unsigned int i = 0; i < num_items; i++) {
user_keys[i] = "keys" + std::to_string(i+100);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + std::to_string(i+100);
// Make all hash values collide.
AddHashLookups(user_keys[i], 0, num_hash_fun);
}
ikey_length = keys[0].size();
value_length = values[0].size();
unique_ptr<WritableFile> writable_file;
fname = test::TmpDir() + "/FailWithTooManyCollisions_writable";
ASSERT_OK(env_->NewWritableFile(fname, &writable_file, env_options_));
CuckooTableBuilder cuckoo_builder(
writable_file.get(), ikey_length,
value_length, hash_table_ratio, file_size, num_hash_fun,
100, GetSliceHash);
ASSERT_OK(cuckoo_builder.status());
for (unsigned int key_idx = 0; key_idx < num_items-1; key_idx++) {
cuckoo_builder.Add(Slice(keys[key_idx]), Slice(values[key_idx]));
ASSERT_OK(cuckoo_builder.status());
ASSERT_EQ(cuckoo_builder.NumEntries(), key_idx + 1);
}
cuckoo_builder.Add(Slice(keys.back()), Slice(values.back()));
ASSERT_TRUE(cuckoo_builder.status().IsCorruption());
cuckoo_builder.Abandon();
writable_file->Close();
}
TEST(CuckooBuilderTest, FailWhenSameKeyInserted) {
hash_map.clear();
std::string user_key = "repeatedkey";
AddHashLookups(user_key, 0, num_hash_fun);
std::string key_to_reuse1, key_to_reuse2;
ParsedInternalKey ikey1(user_key, 1000, kTypeValue);
ParsedInternalKey ikey2(user_key, 1001, kTypeValue);
AppendInternalKey(&key_to_reuse1, ikey1);
AppendInternalKey(&key_to_reuse2, ikey2);
std::string value = "value";
ikey_length = key_to_reuse1.size();
value_length = value.size();
unique_ptr<WritableFile> writable_file;
fname = test::TmpDir() + "/FailWhenSameKeyInserted_writable_file";
ASSERT_OK(env_->NewWritableFile(fname, &writable_file, env_options_));
CuckooTableBuilder cuckoo_builder(
writable_file.get(), ikey_length,
value_length, hash_table_ratio, file_size, num_hash_fun,
100, GetSliceHash);
ASSERT_OK(cuckoo_builder.status());
cuckoo_builder.Add(Slice(key_to_reuse1), Slice(value));
ASSERT_OK(cuckoo_builder.status());
ASSERT_EQ(cuckoo_builder.NumEntries(), 1U);
cuckoo_builder.Add(Slice(key_to_reuse2), Slice(value));
ASSERT_TRUE(cuckoo_builder.status().IsCorruption());
cuckoo_builder.Abandon();
writable_file->Close();
}
TEST(CuckooBuilderTest, WithACollisionPath) {
hash_map.clear();
// Have two hash functions. Insert elements with overlapping hashes.
// Finally insert an element which will displace all the current elements.
num_hash_fun = 2;
unsigned int max_search_depth = 100;
num_items = max_search_depth + 2;
std::vector<std::string> user_keys(num_items);
std::vector<std::string> keys(num_items);
std::vector<std::string> values(num_items);
std::vector<unsigned int> expected_bucket_id(num_items);
for (unsigned int i = 0; i < num_items - 1; i++) {
user_keys[i] = "keys" + std::to_string(i+100);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + std::to_string(i+100);
// Make all hash values collide with the next element.
AddHashLookups(user_keys[i], i, num_hash_fun);
expected_bucket_id[i] = i+1;
}
expected_bucket_id[0] = 0;
user_keys.back() = "keys" + std::to_string(num_items + 99);
ParsedInternalKey ikey(user_keys.back(), num_items + 1000, kTypeValue);
AppendInternalKey(&keys.back(), ikey);
values.back() = "value" + std::to_string(num_items+100);
// Make both hash values collide with first element.
AddHashLookups(user_keys.back(), 0, num_hash_fun);
expected_bucket_id.back() = 1;
ikey_length = keys[0].size();
value_length = values[0].size();
key_length = ikey_length;
bucket_length = key_length + value_length;
expected_max_buckets = file_size / bucket_length;
std::string expected_unused_user_key = "keys10:";
ikey = ParsedInternalKey(expected_unused_user_key, 0, kTypeValue);
AppendInternalKey(&expected_unused_bucket, ikey);
expected_unused_bucket.resize(bucket_length, 'a');
std::string expected_file_data = "";
for (unsigned int i = 0; i < expected_max_buckets; i++) {
expected_file_data += expected_unused_bucket;
}
unique_ptr<WritableFile> writable_file;
fname = test::TmpDir() + "/WithCollisionPath_writable_file";
ASSERT_OK(env_->NewWritableFile(fname, &writable_file, env_options_));
CuckooTableBuilder cuckoo_builder(
writable_file.get(), key_length,
value_length, hash_table_ratio, file_size,
num_hash_fun, max_search_depth, GetSliceHash);
ASSERT_OK(cuckoo_builder.status());
for (unsigned int key_idx = 0; key_idx < num_items; key_idx++) {
cuckoo_builder.Add(Slice(keys[key_idx]), Slice(values[key_idx]));
ASSERT_OK(cuckoo_builder.status());
ASSERT_EQ(cuckoo_builder.NumEntries(), key_idx + 1);
expected_file_data.replace(expected_bucket_id[key_idx]*bucket_length,
bucket_length, keys[key_idx] + values[key_idx]);
}
ASSERT_OK(cuckoo_builder.Finish());
writable_file->Close();
CheckFileContents(expected_file_data);
}
TEST(CuckooBuilderTest, FailWhenCollisionPathTooLong) {
hash_map.clear();
// Have two hash functions. Insert elements with overlapping hashes.
// Finally insert an element which will displace all the current elements.
num_hash_fun = 2;
unsigned int max_search_depth = 100;
num_items = max_search_depth + 3;
std::vector<std::string> user_keys(num_items);
std::vector<std::string> keys(num_items);
std::vector<std::string> values(num_items);
for (unsigned int i = 0; i < num_items - 1; i++) {
user_keys[i] = "keys" + std::to_string(i+100);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + std::to_string(i+100);
// Make all hash values collide with the next element.
AddHashLookups(user_keys[i], i, num_hash_fun);
}
user_keys.back() = "keys" + std::to_string(num_items + 99);
ParsedInternalKey ikey(user_keys.back(), num_items + 1000, kTypeValue);
AppendInternalKey(&keys.back(), ikey);
Slice(values.back()) = "value" + std::to_string(num_items+100);
// Make both hash values collide with first element.
AddHashLookups(user_keys.back(), 0, num_hash_fun);
ikey_length = keys[0].size();
value_length = values[0].size();
unique_ptr<WritableFile> writable_file;
fname = test::TmpDir() + "/FailWhenCollisionPathTooLong_writable";
ASSERT_OK(env_->NewWritableFile(fname, &writable_file, env_options_));
CuckooTableBuilder cuckoo_builder(
writable_file.get(), ikey_length,
value_length, hash_table_ratio, file_size, num_hash_fun,
max_search_depth, GetSliceHash);
ASSERT_OK(cuckoo_builder.status());
for (unsigned int key_idx = 0; key_idx < num_items-1; key_idx++) {
cuckoo_builder.Add(Slice(keys[key_idx]), Slice(values[key_idx]));
ASSERT_OK(cuckoo_builder.status());
ASSERT_EQ(cuckoo_builder.NumEntries(), key_idx + 1);
}
cuckoo_builder.Add(Slice(keys.back()), Slice(values.back()));
ASSERT_TRUE(cuckoo_builder.status().IsCorruption());
cuckoo_builder.Abandon();
writable_file->Close();
}
TEST(CuckooBuilderTest, FailWhenTableIsFull) {
hash_map.clear();
file_size = 160;
num_items = 7;
std::vector<std::string> user_keys(num_items);
std::vector<std::string> keys(num_items);
std::vector<std::string> values(num_items);
for (unsigned int i = 0; i < num_items; i++) {
user_keys[i] = "keys" + std::to_string(i+1000);
ParsedInternalKey ikey(user_keys[i], i + 1000, kTypeValue);
AppendInternalKey(&keys[i], ikey);
values[i] = "value" + std::to_string(i+100);
AddHashLookups(user_keys[i], i, num_hash_fun);
}
ikey_length = keys[0].size();
value_length = values[0].size();
bucket_length = ikey_length + value_length;
// Check that number of items is tight.
ASSERT_GT(bucket_length * num_items, file_size);
ASSERT_LE(bucket_length * (num_items-1), file_size);
unique_ptr<WritableFile> writable_file;
fname = test::TmpDir() + "/FailWhenTabelIsFull_writable";
ASSERT_OK(env_->NewWritableFile(fname, &writable_file, env_options_));
CuckooTableBuilder cuckoo_builder(
writable_file.get(), ikey_length,
value_length, hash_table_ratio, file_size, num_hash_fun,
100, GetSliceHash);
ASSERT_OK(cuckoo_builder.status());
for (unsigned int key_idx = 0; key_idx < num_items-1; key_idx++) {
cuckoo_builder.Add(Slice(keys[key_idx]), Slice(values[key_idx]));
ASSERT_OK(cuckoo_builder.status());
ASSERT_EQ(cuckoo_builder.NumEntries(), key_idx + 1);
}
cuckoo_builder.Add(Slice(keys.back()), Slice(values.back()));
ASSERT_TRUE(cuckoo_builder.status().IsCorruption());
cuckoo_builder.Abandon();
writable_file->Close();
}
} // namespace rocksdb
int main(int argc, char** argv) { return rocksdb::test::RunAllTests(); }