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rocksdb/table/data_block_hash_index_test.cc

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// 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 <cstdlib>
#include <string>
#include <unordered_map>
#include "rocksdb/slice.h"
#include "table/block.h"
#include "table/block_based_table_reader.h"
#include "table/block_builder.h"
#include "table/data_block_hash_index.h"
#include "table/get_context.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace rocksdb {
bool SearchForOffset(DataBlockHashIndex& index, const char* data,
uint16_t map_offset, const Slice& key,
uint8_t& restart_point) {
uint8_t entry = index.Lookup(data, map_offset, key);
if (entry == kCollision) {
return true;
}
if (entry == kNoEntry) {
return false;
}
return entry == restart_point;
}
// Random KV generator similer to block_test
static std::string RandomString(Random* rnd, int len) {
std::string r;
test::RandomString(rnd, len, &r);
return r;
}
std::string GenerateKey(int primary_key, int secondary_key, int padding_size,
Random* rnd) {
char buf[50];
char* p = &buf[0];
snprintf(buf, sizeof(buf), "%6d%4d", primary_key, secondary_key);
std::string k(p);
if (padding_size) {
k += RandomString(rnd, padding_size);
}
return k;
}
// Generate random key value pairs.
// The generated key will be sorted. You can tune the parameters to generated
// different kinds of test key/value pairs for different scenario.
void GenerateRandomKVs(std::vector<std::string>* keys,
std::vector<std::string>* values, const int from,
const int len, const int step = 1,
const int padding_size = 0,
const int keys_share_prefix = 1) {
Random rnd(302);
// generate different prefix
for (int i = from; i < from + len; i += step) {
// generating keys that shares the prefix
for (int j = 0; j < keys_share_prefix; ++j) {
keys->emplace_back(GenerateKey(i, j, padding_size, &rnd));
// 100 bytes values
values->emplace_back(RandomString(&rnd, 100));
}
}
}
TEST(DataBlockHashIndex, DataBlockHashTestSmall) {
DataBlockHashIndexBuilder builder;
builder.Initialize(0.75 /*util_ratio*/);
for (int j = 0; j < 5; j++) {
for (uint8_t i = 0; i < 2 + j; i++) {
std::string key("key" + std::to_string(i));
uint8_t restart_point = i;
builder.Add(key, restart_point);
}
size_t estimated_size = builder.EstimateSize();
std::string buffer("fake"), buffer2;
size_t original_size = buffer.size();
estimated_size += original_size;
builder.Finish(buffer);
ASSERT_EQ(buffer.size(), estimated_size);
buffer2 = buffer; // test for the correctness of relative offset
Slice s(buffer2);
DataBlockHashIndex index;
uint16_t map_offset;
index.Initialize(s.data(), static_cast<uint16_t>(s.size()), &map_offset);
// the additional hash map should start at the end of the buffer
ASSERT_EQ(original_size, map_offset);
for (uint8_t i = 0; i < 2; i++) {
std::string key("key" + std::to_string(i));
uint8_t restart_point = i;
ASSERT_TRUE(
SearchForOffset(index, s.data(), map_offset, key, restart_point));
}
builder.Reset();
}
}
TEST(DataBlockHashIndex, DataBlockHashTest) {
// bucket_num = 200, #keys = 100. 50% utilization
DataBlockHashIndexBuilder builder;
builder.Initialize(0.75 /*util_ratio*/);
for (uint8_t i = 0; i < 100; i++) {
std::string key("key" + std::to_string(i));
uint8_t restart_point = i;
builder.Add(key, restart_point);
}
size_t estimated_size = builder.EstimateSize();
std::string buffer("fake content"), buffer2;
size_t original_size = buffer.size();
estimated_size += original_size;
builder.Finish(buffer);
ASSERT_EQ(buffer.size(), estimated_size);
buffer2 = buffer; // test for the correctness of relative offset
Slice s(buffer2);
DataBlockHashIndex index;
uint16_t map_offset;
index.Initialize(s.data(), static_cast<uint16_t>(s.size()), &map_offset);
// the additional hash map should start at the end of the buffer
ASSERT_EQ(original_size, map_offset);
for (uint8_t i = 0; i < 100; i++) {
std::string key("key" + std::to_string(i));
uint8_t restart_point = i;
ASSERT_TRUE(
SearchForOffset(index, s.data(), map_offset, key, restart_point));
}
}
TEST(DataBlockHashIndex, DataBlockHashTestCollision) {
// bucket_num = 2. There will be intense hash collisions
DataBlockHashIndexBuilder builder;
builder.Initialize(0.75 /*util_ratio*/);
for (uint8_t i = 0; i < 100; i++) {
std::string key("key" + std::to_string(i));
uint8_t restart_point = i;
builder.Add(key, restart_point);
}
size_t estimated_size = builder.EstimateSize();
std::string buffer("some other fake content to take up space"), buffer2;
size_t original_size = buffer.size();
estimated_size += original_size;
builder.Finish(buffer);
ASSERT_EQ(buffer.size(), estimated_size);
buffer2 = buffer; // test for the correctness of relative offset
Slice s(buffer2);
DataBlockHashIndex index;
uint16_t map_offset;
index.Initialize(s.data(), static_cast<uint16_t>(s.size()), &map_offset);
// the additional hash map should start at the end of the buffer
ASSERT_EQ(original_size, map_offset);
for (uint8_t i = 0; i < 100; i++) {
std::string key("key" + std::to_string(i));
uint8_t restart_point = i;
ASSERT_TRUE(
SearchForOffset(index, s.data(), map_offset, key, restart_point));
}
}
TEST(DataBlockHashIndex, DataBlockHashTestLarge) {
DataBlockHashIndexBuilder builder;
builder.Initialize(0.75 /*util_ratio*/);
std::unordered_map<std::string, uint8_t> m;
for (uint8_t i = 0; i < 100; i++) {
if (i % 2) {
continue; // leave half of the keys out
}
std::string key = "key" + std::to_string(i);
uint8_t restart_point = i;
builder.Add(key, restart_point);
m[key] = restart_point;
}
size_t estimated_size = builder.EstimateSize();
std::string buffer("filling stuff"), buffer2;
size_t original_size = buffer.size();
estimated_size += original_size;
builder.Finish(buffer);
ASSERT_EQ(buffer.size(), estimated_size);
buffer2 = buffer; // test for the correctness of relative offset
Slice s(buffer2);
DataBlockHashIndex index;
uint16_t map_offset;
index.Initialize(s.data(), static_cast<uint16_t>(s.size()), &map_offset);
// the additional hash map should start at the end of the buffer
ASSERT_EQ(original_size, map_offset);
for (uint8_t i = 0; i < 100; i++) {
std::string key = "key" + std::to_string(i);
uint8_t restart_point = i;
if (m.count(key)) {
ASSERT_TRUE(m[key] == restart_point);
ASSERT_TRUE(
SearchForOffset(index, s.data(), map_offset, key, restart_point));
} else {
// we allow false positve, so don't test the nonexisting keys.
// when false positive happens, the search will continue to the
// restart intervals to see if the key really exist.
}
}
}
TEST(DataBlockHashIndex, RestartIndexExceedMax) {
DataBlockHashIndexBuilder builder;
builder.Initialize(0.75 /*util_ratio*/);
std::unordered_map<std::string, uint8_t> m;
for (uint8_t i = 0; i <= 253; i++) {
std::string key = "key" + std::to_string(i);
uint8_t restart_point = i;
builder.Add(key, restart_point);
}
ASSERT_TRUE(builder.Valid());
builder.Reset();
for (uint8_t i = 0; i <= 254; i++) {
std::string key = "key" + std::to_string(i);
uint8_t restart_point = i;
builder.Add(key, restart_point);
}
ASSERT_FALSE(builder.Valid());
builder.Reset();
ASSERT_TRUE(builder.Valid());
}
TEST(DataBlockHashIndex, BlockRestartIndexExceedMax) {
Options options = Options();
BlockBuilder builder(1 /* block_restart_interval */,
true /* use_delta_encoding */,
false /* use_value_delta_encoding */,
BlockBasedTableOptions::kDataBlockBinaryAndHash);
// #restarts <= 253. HashIndex is valid
for (int i = 0; i <= 253; i++) {
std::string ukey = "key" + std::to_string(i);
InternalKey ikey(ukey, 0, kTypeValue);
builder.Add(ikey.Encode().ToString(), "value");
}
{
// read serialized contents of the block
Slice rawblock = builder.Finish();
// create block reader
BlockContents contents;
contents.data = rawblock;
contents.cachable = false;
Block reader(std::move(contents), kDisableGlobalSequenceNumber);
ASSERT_EQ(reader.IndexType(),
BlockBasedTableOptions::kDataBlockBinaryAndHash);
}
builder.Reset();
// #restarts > 253. HashIndex is not used
for (int i = 0; i <= 254; i++) {
std::string ukey = "key" + std::to_string(i);
InternalKey ikey(ukey, 0, kTypeValue);
builder.Add(ikey.Encode().ToString(), "value");
}
{
// read serialized contents of the block
Slice rawblock = builder.Finish();
// create block reader
BlockContents contents;
contents.data = rawblock;
contents.cachable = false;
Block reader(std::move(contents), kDisableGlobalSequenceNumber);
ASSERT_EQ(reader.IndexType(),
BlockBasedTableOptions::kDataBlockBinarySearch);
}
}
TEST(DataBlockHashIndex, BlockSizeExceedMax) {
Options options = Options();
std::string ukey(10, 'k');
InternalKey ikey(ukey, 0, kTypeValue);
BlockBuilder builder(1 /* block_restart_interval */,
false /* use_delta_encoding */,
false /* use_value_delta_encoding */,
BlockBasedTableOptions::kDataBlockBinaryAndHash);
{
// insert a large value. The block size plus HashIndex is 65536.
std::string value(65502, 'v');
builder.Add(ikey.Encode().ToString(), value);
// read serialized contents of the block
Slice rawblock = builder.Finish();
ASSERT_LE(rawblock.size(), kMaxBlockSizeSupportedByHashIndex);
std::cerr << "block size: " << rawblock.size() << std::endl;
// create block reader
BlockContents contents;
contents.data = rawblock;
contents.cachable = false;
Block reader(std::move(contents), kDisableGlobalSequenceNumber);
ASSERT_EQ(reader.IndexType(),
BlockBasedTableOptions::kDataBlockBinaryAndHash);
}
builder.Reset();
{
// insert a large value. The block size plus HashIndex would be 65537.
// This excceed the max block size supported by HashIndex (65536).
// So when build finishes HashIndex will not be created for the block.
std::string value(65503, 'v');
builder.Add(ikey.Encode().ToString(), value);
// read serialized contents of the block
Slice rawblock = builder.Finish();
ASSERT_LE(rawblock.size(), kMaxBlockSizeSupportedByHashIndex);
std::cerr << "block size: " << rawblock.size() << std::endl;
// create block reader
BlockContents contents;
contents.data = rawblock;
contents.cachable = false;
Block reader(std::move(contents), kDisableGlobalSequenceNumber);
// the index type have fallen back to binary when build finish.
ASSERT_EQ(reader.IndexType(),
BlockBasedTableOptions::kDataBlockBinarySearch);
}
}
TEST(DataBlockHashIndex, BlockTestSingleKey) {
Options options = Options();
BlockBuilder builder(16 /* block_restart_interval */,
true /* use_delta_encoding */,
false /* use_value_delta_encoding */,
BlockBasedTableOptions::kDataBlockBinaryAndHash);
std::string ukey("gopher");
std::string value("gold");
InternalKey ikey(ukey, 10, kTypeValue);
builder.Add(ikey.Encode().ToString(), value /*value*/);
// read serialized contents of the block
Slice rawblock = builder.Finish();
// create block reader
BlockContents contents;
contents.data = rawblock;
contents.cachable = false;
Block reader(std::move(contents), kDisableGlobalSequenceNumber);
const InternalKeyComparator icmp(BytewiseComparator());
auto iter = reader.NewIterator<DataBlockIter>(&icmp, icmp.user_comparator());
bool may_exist;
// search in block for the key just inserted
{
InternalKey seek_ikey(ukey, 10, kValueTypeForSeek);
may_exist = iter->SeekForGet(seek_ikey.Encode().ToString());
ASSERT_TRUE(may_exist);
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(
options.comparator->Compare(iter->key(), ikey.Encode().ToString()), 0);
ASSERT_EQ(iter->value(), value);
}
// search in block for the existing ukey, but with higher seqno
{
InternalKey seek_ikey(ukey, 20, kValueTypeForSeek);
// HashIndex should be able to set the iter correctly
may_exist = iter->SeekForGet(seek_ikey.Encode().ToString());
ASSERT_TRUE(may_exist);
ASSERT_TRUE(iter->Valid());
// user key should match
ASSERT_EQ(options.comparator->Compare(ExtractUserKey(iter->key()), ukey),
0);
// seek_key seqno number should be greater than that of iter result
ASSERT_GT(GetInternalKeySeqno(seek_ikey.Encode()),
GetInternalKeySeqno(iter->key()));
ASSERT_EQ(iter->value(), value);
}
// Search in block for the existing ukey, but with lower seqno
// in this case, hash can find the only occurrence of the user_key, but
// ParseNextDataKey() will skip it as it does not have a older seqno.
// In this case, GetForSeek() is effective to locate the user_key, and
// iter->Valid() == false indicates that we've reached to the end of
// the block and the caller should continue searching the next block.
{
InternalKey seek_ikey(ukey, 5, kValueTypeForSeek);
may_exist = iter->SeekForGet(seek_ikey.Encode().ToString());
ASSERT_TRUE(may_exist);
ASSERT_FALSE(iter->Valid()); // should have reached to the end of block
}
delete iter;
}
TEST(DataBlockHashIndex, BlockTestLarge) {
Random rnd(1019);
Options options = Options();
std::vector<std::string> keys;
std::vector<std::string> values;
BlockBuilder builder(16 /* block_restart_interval */,
true /* use_delta_encoding */,
false /* use_value_delta_encoding */,
BlockBasedTableOptions::kDataBlockBinaryAndHash);
int num_records = 500;
GenerateRandomKVs(&keys, &values, 0, num_records);
// Generate keys. Adding a trailing "1" to indicate existent keys.
// Later will Seeking for keys with a trailing "0" to test seeking
// non-existent keys.
for (int i = 0; i < num_records; i++) {
std::string ukey(keys[i] + "1" /* existing key marker */);
InternalKey ikey(ukey, 0, kTypeValue);
builder.Add(ikey.Encode().ToString(), values[i]);
}
// read serialized contents of the block
Slice rawblock = builder.Finish();
// create block reader
BlockContents contents;
contents.data = rawblock;
contents.cachable = false;
Block reader(std::move(contents), kDisableGlobalSequenceNumber);
const InternalKeyComparator icmp(BytewiseComparator());
// random seek existent keys
for (int i = 0; i < num_records; i++) {
auto iter =
reader.NewIterator<DataBlockIter>(&icmp, icmp.user_comparator());
// find a random key in the lookaside array
int index = rnd.Uniform(num_records);
std::string ukey(keys[index] + "1" /* existing key marker */);
InternalKey ikey(ukey, 0, kTypeValue);
// search in block for this key
bool may_exist = iter->SeekForGet(ikey.Encode().ToString());
ASSERT_TRUE(may_exist);
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(values[index], iter->value());
delete iter;
}
// random seek non-existent user keys
// In this case A), the user_key cannot be found in HashIndex. The key may
// exist in the next block. So the iter is set invalidated to tell the
// caller to search the next block. This test case belongs to this case A).
//
// Note that for non-existent keys, there is possibility of false positive,
// i.e. the key is still hashed into some restart interval.
// Two additional possible outcome:
// B) linear seek the restart interval and not found, the iter stops at the
// starting of the next restart interval. The key does not exist
// anywhere.
// C) linear seek the restart interval and not found, the iter stops at the
// the end of the block, i.e. restarts_. The key may exist in the next
// block.
// So these combinations are possible when searching non-existent user_key:
//
// case# may_exist iter->Valid()
// A true false
// B false true
// C true false
for (int i = 0; i < num_records; i++) {
auto iter =
reader.NewIterator<DataBlockIter>(&icmp, icmp.user_comparator());
// find a random key in the lookaside array
int index = rnd.Uniform(num_records);
std::string ukey(keys[index] + "0" /* non-existing key marker */);
InternalKey ikey(ukey, 0, kTypeValue);
// search in block for this key
bool may_exist = iter->SeekForGet(ikey.Encode().ToString());
if (!may_exist) {
ASSERT_TRUE(iter->Valid());
}
if (!iter->Valid()) {
ASSERT_TRUE(may_exist);
}
delete iter;
}
}
// helper routine for DataBlockHashIndex.BlockBoundary
void TestBoundary(InternalKey& ik1, std::string& v1, InternalKey& ik2,
std::string& v2, InternalKey& seek_ikey,
GetContext& get_context, Options& options) {
unique_ptr<WritableFileWriter> file_writer;
unique_ptr<RandomAccessFileReader> file_reader;
unique_ptr<TableReader> table_reader;
int level_ = -1;
std::vector<std::string> keys;
const ImmutableCFOptions ioptions(options);
const MutableCFOptions moptions(options);
const InternalKeyComparator internal_comparator(options.comparator);
EnvOptions soptions;
soptions.use_mmap_reads = ioptions.allow_mmap_reads;
file_writer.reset(test::GetWritableFileWriter(new test::StringSink()));
unique_ptr<TableBuilder> builder;
std::vector<std::unique_ptr<IntTblPropCollectorFactory>>
int_tbl_prop_collector_factories;
std::string column_family_name;
builder.reset(ioptions.table_factory->NewTableBuilder(
TableBuilderOptions(ioptions, moptions, internal_comparator,
&int_tbl_prop_collector_factories,
options.compression, CompressionOptions(),
nullptr /* compression_dict */,
false /* skip_filters */, column_family_name, level_),
TablePropertiesCollectorFactory::Context::kUnknownColumnFamily,
file_writer.get()));
builder->Add(ik1.Encode().ToString(), v1);
builder->Add(ik2.Encode().ToString(), v2);
EXPECT_TRUE(builder->status().ok());
Status s = builder->Finish();
file_writer->Flush();
EXPECT_TRUE(s.ok()) << s.ToString();
EXPECT_EQ(static_cast<test::StringSink*>(file_writer->writable_file())
->contents()
.size(),
builder->FileSize());
// Open the table
file_reader.reset(test::GetRandomAccessFileReader(new test::StringSource(
static_cast<test::StringSink*>(file_writer->writable_file())->contents(),
0 /*uniq_id*/, ioptions.allow_mmap_reads)));
const bool kSkipFilters = true;
const bool kImmortal = true;
ioptions.table_factory->NewTableReader(
TableReaderOptions(ioptions, moptions.prefix_extractor.get(), soptions,
internal_comparator, !kSkipFilters, !kImmortal,
level_),
std::move(file_reader),
static_cast<test::StringSink*>(file_writer->writable_file())
->contents()
.size(),
&table_reader);
// Search using Get()
ReadOptions ro;
ASSERT_OK(table_reader->Get(ro, seek_ikey.Encode().ToString(), &get_context,
moptions.prefix_extractor.get()));
}
TEST(DataBlockHashIndex, BlockBoundary) {
BlockBasedTableOptions table_options;
table_options.data_block_index_type =
BlockBasedTableOptions::kDataBlockBinaryAndHash;
table_options.block_restart_interval = 1;
table_options.block_size = 4096;
Options options;
options.comparator = BytewiseComparator();
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
// insert two large k/v pair. Given that the block_size is 4096, one k/v
// pair will take up one block.
// [ k1/v1 ][ k2/v2 ]
// [ Block N ][ Block N+1 ]
{
// [ "aab"@100 ][ "axy"@10 ]
// | Block N ][ Block N+1 ]
// seek for "axy"@60
std::string uk1("aab");
InternalKey ik1(uk1, 100, kTypeValue);
std::string v1(4100, '1'); // large value
std::string uk2("axy");
InternalKey ik2(uk2, 10, kTypeValue);
std::string v2(4100, '2'); // large value
PinnableSlice value;
std::string seek_ukey("axy");
InternalKey seek_ikey(seek_ukey, 60, kTypeValue);
GetContext get_context(options.comparator, nullptr, nullptr, nullptr,
GetContext::kNotFound, seek_ukey, &value, nullptr,
nullptr, nullptr, nullptr);
TestBoundary(ik1, v1, ik2, v2, seek_ikey, get_context, options);
ASSERT_EQ(get_context.State(), GetContext::kFound);
ASSERT_EQ(value, v2);
value.Reset();
}
{
// [ "axy"@100 ][ "axy"@10 ]
// | Block N ][ Block N+1 ]
// seek for "axy"@60
std::string uk1("axy");
InternalKey ik1(uk1, 100, kTypeValue);
std::string v1(4100, '1'); // large value
std::string uk2("axy");
InternalKey ik2(uk2, 10, kTypeValue);
std::string v2(4100, '2'); // large value
PinnableSlice value;
std::string seek_ukey("axy");
InternalKey seek_ikey(seek_ukey, 60, kTypeValue);
GetContext get_context(options.comparator, nullptr, nullptr, nullptr,
GetContext::kNotFound, seek_ukey, &value, nullptr,
nullptr, nullptr, nullptr);
TestBoundary(ik1, v1, ik2, v2, seek_ikey, get_context, options);
ASSERT_EQ(get_context.State(), GetContext::kFound);
ASSERT_EQ(value, v2);
value.Reset();
}
{
// [ "axy"@100 ][ "axy"@10 ]
// | Block N ][ Block N+1 ]
// seek for "axy"@120
std::string uk1("axy");
InternalKey ik1(uk1, 100, kTypeValue);
std::string v1(4100, '1'); // large value
std::string uk2("axy");
InternalKey ik2(uk2, 10, kTypeValue);
std::string v2(4100, '2'); // large value
PinnableSlice value;
std::string seek_ukey("axy");
InternalKey seek_ikey(seek_ukey, 120, kTypeValue);
GetContext get_context(options.comparator, nullptr, nullptr, nullptr,
GetContext::kNotFound, seek_ukey, &value, nullptr,
nullptr, nullptr, nullptr);
TestBoundary(ik1, v1, ik2, v2, seek_ikey, get_context, options);
ASSERT_EQ(get_context.State(), GetContext::kFound);
ASSERT_EQ(value, v1);
value.Reset();
}
{
// [ "axy"@100 ][ "axy"@10 ]
// | Block N ][ Block N+1 ]
// seek for "axy"@5
std::string uk1("axy");
InternalKey ik1(uk1, 100, kTypeValue);
std::string v1(4100, '1'); // large value
std::string uk2("axy");
InternalKey ik2(uk2, 10, kTypeValue);
std::string v2(4100, '2'); // large value
PinnableSlice value;
std::string seek_ukey("axy");
InternalKey seek_ikey(seek_ukey, 5, kTypeValue);
GetContext get_context(options.comparator, nullptr, nullptr, nullptr,
GetContext::kNotFound, seek_ukey, &value, nullptr,
nullptr, nullptr, nullptr);
TestBoundary(ik1, v1, ik2, v2, seek_ikey, get_context, options);
ASSERT_EQ(get_context.State(), GetContext::kNotFound);
value.Reset();
}
}
} // namespace rocksdb
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}