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Implement full filter for block based table. 

Summary:
1. Make filter_block.h a base class. Derive block_based_filter_block and full_filter_block. The previous one is the traditional filter block. The full_filter_block is newly added. It would generate a filter block that contain all the keys in SST file.

2. When querying a key, table would first check if full_filter is available. If not, it would go to the exact data block and check using block_based filter.

3. User could choose to use full_filter or tradional(block_based_filter). They would be stored in SST file with different meta index name. "filter.filter_policy" or "full_filter.filter_policy". Then, Table reader is able to know the fllter block type.

4. Some optimizations have been done for full_filter_block, thus it requires a different interface compared to the original one in filter_policy.h.

5. Actual implementation of filter bits coding/decoding is placed in util/bloom_impl.cc

Benchmark: base commit 1d23b5c470
Command:
db_bench --db=/dev/shm/rocksdb --num_levels=6 --key_size=20 --prefix_size=20 --keys_per_prefix=0 --value_size=100 --write_buffer_size=134217728 --max_write_buffer_number=2 --target_file_size_base=33554432 --max_bytes_for_level_base=1073741824 --verify_checksum=false --max_background_compactions=4 --use_plain_table=0 --memtablerep=prefix_hash --open_files=-1 --mmap_read=1 --mmap_write=0 --bloom_bits=10 --bloom_locality=1 --memtable_bloom_bits=500000 --compression_type=lz4 --num=393216000 --use_hash_search=1 --block_size=1024 --block_restart_interval=16 --use_existing_db=1 --threads=1 --benchmarks=readrandom —disable_auto_compactions=1
Read QPS increase for about 30% from 2230002 to 2991411.

Test Plan:
make all check
valgrind db_test
db_stress --use_block_based_filter = 0
./auto_sanity_test.sh

Reviewers: igor, yhchiang, ljin, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D20979
This commit is contained in:
Feng Zhu 2014-09-08 10:37:05 -07:00
parent 9360cc690e
commit 0af157f9bf
23 changed files with 1707 additions and 482 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
Makefile
View File

@ -90,7 +90,8 @@ TESTS = \
blob_store_test \
filelock_test \
filename_test \
filter_block_test \
block_based_filter_block_test \
full_filter_block_test \
histogram_test \
log_test \
manual_compaction_test \
@ -393,8 +394,11 @@ rate_limiter_test: util/rate_limiter_test.o $(LIBOBJECTS) $(TESTHARNESS)
filename_test: db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(CXX) db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
filter_block_test: table/filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(CXX) table/filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
block_based_filter_block_test: table/block_based_filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(CXX) table/block_based_filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
full_filter_block_test: table/full_filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(CXX) table/full_filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
log_test: db/log_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(CXX) db/log_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

2
db/c.cc
View File

@ -118,7 +118,7 @@ struct rocksdb_compactionfilter_t : public CompactionFilter {
const Slice& existing_value,
std::string* new_value,
bool* value_changed) const {
char* c_new_value = NULL;
char* c_new_value = nullptr;
size_t new_value_length = 0;
unsigned char c_value_changed = 0;
unsigned char result = (*filter_)(

12
db/db_bench.cc
View File

@ -39,8 +39,8 @@ int main() {
#include "rocksdb/memtablerep.h"
#include "rocksdb/write_batch.h"
#include "rocksdb/slice.h"
#include "rocksdb/filter_policy.h"
#include "rocksdb/slice_transform.h"
#include "rocksdb/statistics.h"
#include "rocksdb/perf_context.h"
#include "port/port.h"
#include "port/stack_trace.h"
@ -553,7 +553,9 @@ DEFINE_double(cuckoo_hash_ratio, 0.9, "Hash ratio for Cuckoo SST table.");
DEFINE_bool(use_hash_search, false, "if use kHashSearch "
"instead of kBinarySearch. "
"This is valid if only we use BlockTable");
DEFINE_bool(use_block_based_filter, false, "if use kBlockBasedFilter "
"instead of kFullFilter for filter block. "
"This is valid if only we use BlockTable");
DEFINE_string(merge_operator, "", "The merge operator to use with the database."
"If a new merge operator is specified, be sure to use fresh"
" database The possible merge operators are defined in"
@ -1076,9 +1078,9 @@ class Benchmark {
(FLAGS_cache_numshardbits >= 1 ?
NewLRUCache(FLAGS_compressed_cache_size, FLAGS_cache_numshardbits) :
NewLRUCache(FLAGS_compressed_cache_size)) : nullptr),
filter_policy_(FLAGS_bloom_bits >= 0
? NewBloomFilterPolicy(FLAGS_bloom_bits)
: nullptr),
filter_policy_(FLAGS_bloom_bits >= 0 ?
NewBloomFilterPolicy(FLAGS_bloom_bits, FLAGS_use_block_based_filter)
: nullptr),
prefix_extractor_(NewFixedPrefixTransform(FLAGS_prefix_size)),
num_(FLAGS_num),
value_size_(FLAGS_value_size),

224
db/db_test.cc
View File

@ -324,21 +324,22 @@ class DBTest {
kHashCuckoo = 7,
kMergePut = 8,
kFilter = 9,
kUncompressed = 10,
kNumLevel_3 = 11,
kDBLogDir = 12,
kWalDir = 13,
kManifestFileSize = 14,
kCompactOnFlush = 15,
kPerfOptions = 16,
kDeletesFilterFirst = 17,
kHashSkipList = 18,
kUniversalCompaction = 19,
kCompressedBlockCache = 20,
kInfiniteMaxOpenFiles = 21,
kxxHashChecksum = 22,
kFIFOCompaction = 23,
kEnd = 24
kFullFilter = 10,
kUncompressed = 11,
kNumLevel_3 = 12,
kDBLogDir = 13,
kWalDir = 14,
kManifestFileSize = 15,
kCompactOnFlush = 16,
kPerfOptions = 17,
kDeletesFilterFirst = 18,
kHashSkipList = 19,
kUniversalCompaction = 20,
kCompressedBlockCache = 21,
kInfiniteMaxOpenFiles = 22,
kxxHashChecksum = 23,
kFIFOCompaction = 24,
kEnd = 25
};
int option_config_;
@ -448,6 +449,30 @@ class DBTest {
}
}
// Switch between different filter policy
// Jump from kDefault to kFilter to kFullFilter
bool ChangeFilterOptions(Options* prev_options = nullptr) {
if (option_config_ == kDefault) {
option_config_ = kFilter;
if (prev_options == nullptr) {
prev_options = &last_options_;
}
Destroy(prev_options);
TryReopen();
return true;
} else if (option_config_ == kFilter) {
option_config_ = kFullFilter;
if (prev_options == nullptr) {
prev_options = &last_options_;
}
Destroy(prev_options);
TryReopen();
return true;
} else {
return false;
}
}
// Return the current option configuration.
Options CurrentOptions(
const anon::OptionsOverride& options_override = anon::OptionsOverride()) {
@ -486,7 +511,10 @@ class DBTest {
options.merge_operator = MergeOperators::CreatePutOperator();
break;
case kFilter:
table_options.filter_policy.reset(NewBloomFilterPolicy(10));
table_options.filter_policy.reset(NewBloomFilterPolicy(10, true));
break;
case kFullFilter:
table_options.filter_policy.reset(NewBloomFilterPolicy(10, false));
break;
case kUncompressed:
options.compression = kNoCompression;
@ -5744,6 +5772,92 @@ TEST(DBTest, BloomFilter) {
} while (ChangeCompactOptions());
}
TEST(DBTest, BloomFilterRate) {
while (ChangeFilterOptions()) {
Options options = CurrentOptions();
options.statistics = rocksdb::CreateDBStatistics();
CreateAndReopenWithCF({"pikachu"}, &options);
const int maxKey = 10000;
for (int i = 0; i < maxKey; i++) {
ASSERT_OK(Put(1, Key(i), Key(i)));
}
// Add a large key to make the file contain wide range
ASSERT_OK(Put(1, Key(maxKey + 55555), Key(maxKey + 55555)));
Flush(1);
// Check if they can be found
for (int i = 0; i < maxKey; i++) {
ASSERT_EQ(Key(i), Get(1, Key(i)));
}
ASSERT_EQ(TestGetTickerCount(options, BLOOM_FILTER_USEFUL), 0);
// Check if filter is useful
for (int i = 0; i < maxKey; i++) {
ASSERT_EQ("NOT_FOUND", Get(1, Key(i+33333)));
}
ASSERT_GE(TestGetTickerCount(options, BLOOM_FILTER_USEFUL), maxKey*0.98);
}
}
TEST(DBTest, BloomFilterCompatibility) {
Options options;
options.statistics = rocksdb::CreateDBStatistics();
BlockBasedTableOptions table_options;
table_options.filter_policy.reset(NewBloomFilterPolicy(10, true));
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
// Create with block based filter
CreateAndReopenWithCF({"pikachu"}, &options);
const int maxKey = 10000;
for (int i = 0; i < maxKey; i++) {
ASSERT_OK(Put(1, Key(i), Key(i)));
}
ASSERT_OK(Put(1, Key(maxKey + 55555), Key(maxKey + 55555)));
Flush(1);
// Check db with full filter
table_options.filter_policy.reset(NewBloomFilterPolicy(10, false));
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
ReopenWithColumnFamilies({"default", "pikachu"}, &options);
// Check if they can be found
for (int i = 0; i < maxKey; i++) {
ASSERT_EQ(Key(i), Get(1, Key(i)));
}
ASSERT_EQ(TestGetTickerCount(options, BLOOM_FILTER_USEFUL), 0);
}
TEST(DBTest, BloomFilterReverseCompatibility) {
Options options;
options.statistics = rocksdb::CreateDBStatistics();
BlockBasedTableOptions table_options;
table_options.filter_policy.reset(NewBloomFilterPolicy(10, false));
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
// Create with full filter
CreateAndReopenWithCF({"pikachu"}, &options);
const int maxKey = 10000;
for (int i = 0; i < maxKey; i++) {
ASSERT_OK(Put(1, Key(i), Key(i)));
}
ASSERT_OK(Put(1, Key(maxKey + 55555), Key(maxKey + 55555)));
Flush(1);
// Check db with block_based filter
table_options.filter_policy.reset(NewBloomFilterPolicy(10, true));
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
ReopenWithColumnFamilies({"default", "pikachu"}, &options);
// Check if they can be found
for (int i = 0; i < maxKey; i++) {
ASSERT_EQ(Key(i), Get(1, Key(i)));
}
ASSERT_EQ(TestGetTickerCount(options, BLOOM_FILTER_USEFUL), 0);
}
TEST(DBTest, SnapshotFiles) {
do {
Options options = CurrentOptions();
@ -7194,47 +7308,49 @@ void PrefixScanInit(DBTest *dbtest) {
} // namespace
TEST(DBTest, PrefixScan) {
int count;
Slice prefix;
Slice key;
char buf[100];
Iterator* iter;
snprintf(buf, sizeof(buf), "03______:");
prefix = Slice(buf, 8);
key = Slice(buf, 9);
// db configs
env_->count_random_reads_ = true;
Options options = CurrentOptions();
options.env = env_;
options.prefix_extractor.reset(NewFixedPrefixTransform(8));
options.disable_auto_compactions = true;
options.max_background_compactions = 2;
options.create_if_missing = true;
options.memtable_factory.reset(NewHashSkipListRepFactory(16));
while (ChangeFilterOptions()) {
int count;
Slice prefix;
Slice key;
char buf[100];
Iterator* iter;
snprintf(buf, sizeof(buf), "03______:");
prefix = Slice(buf, 8);
key = Slice(buf, 9);
// db configs
env_->count_random_reads_ = true;
Options options = CurrentOptions();
options.env = env_;
options.prefix_extractor.reset(NewFixedPrefixTransform(8));
options.disable_auto_compactions = true;
options.max_background_compactions = 2;
options.create_if_missing = true;
options.memtable_factory.reset(NewHashSkipListRepFactory(16));
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.filter_policy.reset(NewBloomFilterPolicy(10));
table_options.whole_key_filtering = false;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.filter_policy.reset(NewBloomFilterPolicy(10));
table_options.whole_key_filtering = false;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
// 11 RAND I/Os
DestroyAndReopen(&options);
PrefixScanInit(this);
count = 0;
env_->random_read_counter_.Reset();
iter = db_->NewIterator(ReadOptions());
for (iter->Seek(prefix); iter->Valid(); iter->Next()) {
if (! iter->key().starts_with(prefix)) {
break;
// 11 RAND I/Os
DestroyAndReopen(&options);
PrefixScanInit(this);
count = 0;
env_->random_read_counter_.Reset();
iter = db_->NewIterator(ReadOptions());
for (iter->Seek(prefix); iter->Valid(); iter->Next()) {
if (! iter->key().starts_with(prefix)) {
break;
}
count++;
}
count++;
}
ASSERT_OK(iter->status());
delete iter;
ASSERT_EQ(count, 2);
ASSERT_EQ(env_->random_read_counter_.Read(), 2);
Close();
ASSERT_OK(iter->status());
delete iter;
ASSERT_EQ(count, 2);
ASSERT_EQ(env_->random_read_counter_.Read(), 2);
Close();
} // end of while
}
TEST(DBTest, TailingIteratorSingle) {

64
include/rocksdb/filter_policy.h
View File

@ -21,11 +21,52 @@
#define STORAGE_ROCKSDB_INCLUDE_FILTER_POLICY_H_
#include <string>
#include <memory>
namespace rocksdb {
class Slice;
// A class that takes a bunch of keys, then generates filter
class FilterBitsBuilder {
public:
virtual ~FilterBitsBuilder() {}
// Add Key to filter, you could use any way to store the key.
// Such as: storing hashes or original keys
// Keys are in sorted order and duplicated keys are possible.
virtual void AddKey(const Slice& key) = 0;
// Generate the filter using the keys that are added
// The return value of this function would be the filter bits,
// The ownership of actual data is set to buf
virtual Slice Finish(std::unique_ptr<const char[]>* buf) = 0;
};
// A class that checks if a key can be in filter
// It should be initialized by Slice generated by BitsBuilder
class FilterBitsReader {
public:
virtual ~FilterBitsReader() {}
// Check if the entry match the bits in filter
virtual bool MayMatch(const Slice& entry) = 0;
};
// We add a new format of filter block called full filter block
// This new interface gives you more space of customization
//
// For the full filter block, you can plug in your version by implement
// the FilterBitsBuilder and FilterBitsReader
//
// There are two sets of interface in FilterPolicy
// Set 1: CreateFilter, KeyMayMatch: used for blockbased filter
// Set 2: GetFilterBitsBuilder, GetFilterBitsReader, they are used for
// full filter.
// Set 1 MUST be implemented correctly, Set 2 is optional
// RocksDB would first try using functions in Set 2. if they return nullptr,
// it would use Set 1 instead.
// You can choose filter type in NewBloomFilterPolicy
class FilterPolicy {
public:
virtual ~FilterPolicy();
@ -51,11 +92,28 @@ class FilterPolicy {
// This method may return true or false if the key was not on the
// list, but it should aim to return false with a high probability.
virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const = 0;
// Get the FilterBitsBuilder, which is ONLY used for full filter block
// It contains interface to take individual key, then generate filter
virtual FilterBitsBuilder* GetFilterBitsBuilder() const {
return nullptr;
}
// Get the FilterBitsReader, which is ONLY used for full filter block
// It contains interface to tell if key can be in filter
// The input slice should NOT be deleted by FilterPolicy
virtual FilterBitsReader* GetFilterBitsReader(const Slice& contents) const {
return nullptr;
}
};
// Return a new filter policy that uses a bloom filter with approximately
// the specified number of bits per key. A good value for bits_per_key
// the specified number of bits per key.
//
// bits_per_key: bits per key in bloom filter. A good value for bits_per_key
// is 10, which yields a filter with ~ 1% false positive rate.
// use_block_based_builder: use block based filter rather than full fiter.
// If you want to builder full filter, it needs to be set to false.
//
// Callers must delete the result after any database that is using the
// result has been closed.
@ -67,8 +125,8 @@ class FilterPolicy {
// ignores trailing spaces, it would be incorrect to use a
// FilterPolicy (like NewBloomFilterPolicy) that does not ignore
// trailing spaces in keys.
extern const FilterPolicy* NewBloomFilterPolicy(int bits_per_key);
extern const FilterPolicy* NewBloomFilterPolicy(int bits_per_key,
bool use_block_based_builder = true);
}
#endif // STORAGE_ROCKSDB_INCLUDE_FILTER_POLICY_H_

2
include/rocksdb/statistics.h
View File

@ -115,7 +115,7 @@ enum Tickers : uint32_t {
// head of the writers queue.
WRITE_DONE_BY_SELF,
WRITE_DONE_BY_OTHER,
WRITE_TIMEDOUT, // Number of writes ending up with timed-out.
WRITE_TIMEDOUT, // Number of writes ending up with timed-out.
WRITE_WITH_WAL, // Number of Write calls that request WAL
COMPACT_READ_BYTES, // Bytes read during compaction
COMPACT_WRITE_BYTES, // Bytes written during compaction

124
table/filter_block.cc → table/block_based_filter_block.cc
View File

@ -7,7 +7,7 @@
// 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 "table/filter_block.h"
#include "table/block_based_filter_block.h"
#include "db/dbformat.h"
#include "rocksdb/filter_policy.h"
@ -15,21 +15,39 @@
namespace rocksdb {
namespace {
bool SamePrefix(const SliceTransform* prefix_extractor,
const Slice& key1, const Slice& key2) {
if (!prefix_extractor->InDomain(key1) &&
!prefix_extractor->InDomain(key2)) {
return true;
} else if (!prefix_extractor->InDomain(key1) ||
!prefix_extractor->InDomain(key2)) {
return false;
} else {
return (prefix_extractor->Transform(key1) ==
prefix_extractor->Transform(key2));
}
}
} // namespace
// See doc/table_format.txt for an explanation of the filter block format.
// Generate new filter every 2KB of data
static const size_t kFilterBaseLg = 11;
static const size_t kFilterBase = 1 << kFilterBaseLg;
FilterBlockBuilder::FilterBlockBuilder(const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
const Comparator* internal_comparator)
BlockBasedFilterBlockBuilder::BlockBasedFilterBlockBuilder(
const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt)
: policy_(table_opt.filter_policy.get()),
prefix_extractor_(prefix_extractor),
whole_key_filtering_(table_opt.whole_key_filtering),
comparator_(internal_comparator) {}
whole_key_filtering_(table_opt.whole_key_filtering) {
assert(policy_);
}
void FilterBlockBuilder::StartBlock(uint64_t block_offset) {
void BlockBasedFilterBlockBuilder::StartBlock(uint64_t block_offset) {
uint64_t filter_index = (block_offset / kFilterBase);
assert(filter_index >= filter_offsets_.size());
while (filter_index > filter_offsets_.size()) {
@ -37,53 +55,45 @@ void FilterBlockBuilder::StartBlock(uint64_t block_offset) {
}
}
bool FilterBlockBuilder::SamePrefix(const Slice &key1,
const Slice &key2) const {
if (!prefix_extractor_->InDomain(key1) &&
!prefix_extractor_->InDomain(key2)) {
return true;
} else if (!prefix_extractor_->InDomain(key1) ||
!prefix_extractor_->InDomain(key2)) {
return false;
} else {
return (prefix_extractor_->Transform(key1) ==
prefix_extractor_->Transform(key2));
void BlockBasedFilterBlockBuilder::Add(const Slice& key) {
added_to_start_ = 0;
if (whole_key_filtering_) {
AddKey(key);
added_to_start_ = 1;
}
if (prefix_extractor_ && prefix_extractor_->InDomain(key)) {
AddPrefix(key);
}
}
void FilterBlockBuilder::AddKey(const Slice& key) {
// Add key to filter if needed
inline void BlockBasedFilterBlockBuilder::AddKey(const Slice& key) {
start_.push_back(entries_.size());
entries_.append(key.data(), key.size());
}
// Add prefix to filter if needed
inline void BlockBasedFilterBlockBuilder::AddPrefix(const Slice& key) {
// get slice for most recently added entry
Slice prev;
size_t added_to_start = 0;
// add key to filter if needed
if (whole_key_filtering_) {
start_.push_back(entries_.size());
++added_to_start;
entries_.append(key.data(), key.size());
}
if (start_.size() > added_to_start) {
size_t prev_start = start_[start_.size() - 1 - added_to_start];
if (start_.size() > added_to_start_) {
size_t prev_start = start_[start_.size() - 1 - added_to_start_];
const char* base = entries_.data() + prev_start;
size_t length = entries_.size() - prev_start;
prev = Slice(base, length);
}
// add prefix to filter if needed
if (prefix_extractor_ && prefix_extractor_->InDomain(key)) {
// this assumes prefix(prefix(key)) == prefix(key), as the last
// entry in entries_ may be either a key or prefix, and we use
// prefix(last entry) to get the prefix of the last key.
if (prev.size() == 0 || !SamePrefix(key, prev)) {
Slice prefix = prefix_extractor_->Transform(key);
start_.push_back(entries_.size());
entries_.append(prefix.data(), prefix.size());
}
// this assumes prefix(prefix(key)) == prefix(key), as the last
// entry in entries_ may be either a key or prefix, and we use
// prefix(last entry) to get the prefix of the last key.
if (prev.size() == 0 || !SamePrefix(prefix_extractor_, key, prev)) {
Slice prefix = prefix_extractor_->Transform(key);
start_.push_back(entries_.size());
entries_.append(prefix.data(), prefix.size());
}
}
Slice FilterBlockBuilder::Finish() {
Slice BlockBasedFilterBlockBuilder::Finish() {
if (!start_.empty()) {
GenerateFilter();
}
@ -99,7 +109,7 @@ Slice FilterBlockBuilder::Finish() {
return Slice(result_);
}
void FilterBlockBuilder::GenerateFilter() {
void BlockBasedFilterBlockBuilder::GenerateFilter() {
const size_t num_entries = start_.size();
if (num_entries == 0) {
// Fast path if there are no keys for this filter
@ -112,7 +122,7 @@ void FilterBlockBuilder::GenerateFilter() {
tmp_entries_.resize(num_entries);
for (size_t i = 0; i < num_entries; i++) {
const char* base = entries_.data() + start_[i];
size_t length = start_[i+1] - start_[i];
size_t length = start_[i + 1] - start_[i];
tmp_entries_[i] = Slice(base, length);
}
@ -125,7 +135,7 @@ void FilterBlockBuilder::GenerateFilter() {
start_.clear();
}
FilterBlockReader::FilterBlockReader(
BlockBasedFilterBlockReader::BlockBasedFilterBlockReader(
const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
const Slice& contents, bool delete_contents_after_use)
@ -136,9 +146,10 @@ FilterBlockReader::FilterBlockReader(
offset_(nullptr),
num_(0),
base_lg_(0) {
assert(policy_);
size_t n = contents.size();
if (n < 5) return; // 1 byte for base_lg_ and 4 for start of offset array
base_lg_ = contents[n-1];
base_lg_ = contents[n - 1];
uint32_t last_word = DecodeFixed32(contents.data() + n - 5);
if (last_word > n - 5) return;
data_ = contents.data();
@ -149,27 +160,30 @@ FilterBlockReader::FilterBlockReader(
}
}
bool FilterBlockReader::KeyMayMatch(uint64_t block_offset,
const Slice& key) {
bool BlockBasedFilterBlockReader::KeyMayMatch(const Slice& key,
uint64_t block_offset) {
assert(block_offset != kNotValid);
if (!whole_key_filtering_) {
return true;
}
return MayMatch(block_offset, key);
return MayMatch(key, block_offset);
}
bool FilterBlockReader::PrefixMayMatch(uint64_t block_offset,
const Slice& prefix) {
bool BlockBasedFilterBlockReader::PrefixMayMatch(const Slice& prefix,
uint64_t block_offset) {
assert(block_offset != kNotValid);
if (!prefix_extractor_) {
return true;
}
return MayMatch(block_offset, prefix);
return MayMatch(prefix, block_offset);
}
bool FilterBlockReader::MayMatch(uint64_t block_offset, const Slice& entry) {
bool BlockBasedFilterBlockReader::MayMatch(const Slice& entry,
uint64_t block_offset) {
uint64_t index = block_offset >> base_lg_;
if (index < num_) {
uint32_t start = DecodeFixed32(offset_ + index*4);
uint32_t limit = DecodeFixed32(offset_ + index*4 + 4);
uint32_t start = DecodeFixed32(offset_ + index * 4);
uint32_t limit = DecodeFixed32(offset_ + index * 4 + 4);
if (start <= limit && limit <= (uint32_t)(offset_ - data_)) {
Slice filter = Slice(data_ + start, limit - start);
return policy_->KeyMayMatch(entry, filter);
@ -181,7 +195,7 @@ bool FilterBlockReader::MayMatch(uint64_t block_offset, const Slice& entry) {
return true; // Errors are treated as potential matches
}
size_t FilterBlockReader::ApproximateMemoryUsage() const {
size_t BlockBasedFilterBlockReader::ApproximateMemoryUsage() const {
return num_ * 4 + 5 + (offset_ - data_);
}
}

102
table/block_based_filter_block.h Normal file
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@ -0,0 +1,102 @@
// 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.
//
// Copyright (c) 2012 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.
//
// A filter block is stored near the end of a Table file. It contains
// filters (e.g., bloom filters) for all data blocks in the table combined
// into a single filter block.
#pragma once
#include <stddef.h>
#include <stdint.h>
#include <string>
#include <memory>
#include <vector>
#include "rocksdb/options.h"
#include "rocksdb/slice.h"
#include "rocksdb/slice_transform.h"
#include "table/filter_block.h"
#include "util/hash.h"
namespace rocksdb {
// A BlockBasedFilterBlockBuilder is used to construct all of the filters for a
// particular Table. It generates a single string which is stored as
// a special block in the Table.
//
// The sequence of calls to BlockBasedFilterBlockBuilder must match the regexp:
// (StartBlock Add*)* Finish
class BlockBasedFilterBlockBuilder : public FilterBlockBuilder {
public:
BlockBasedFilterBlockBuilder(const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt);
virtual bool IsBlockBased() override { return true; }
virtual void StartBlock(uint64_t block_offset) override;
virtual void Add(const Slice& key) override;
virtual Slice Finish() override;
private:
void AddKey(const Slice& key);
void AddPrefix(const Slice& key);
void GenerateFilter();
// important: all of these might point to invalid addresses
// at the time of destruction of this filter block. destructor
// should NOT dereference them.
const FilterPolicy* policy_;
const SliceTransform* prefix_extractor_;
bool whole_key_filtering_;
std::string entries_; // Flattened entry contents
std::vector<size_t> start_; // Starting index in entries_ of each entry
uint32_t added_to_start_; // To indicate if key is added
std::string result_; // Filter data computed so far
std::vector<Slice> tmp_entries_; // policy_->CreateFilter() argument
std::vector<uint32_t> filter_offsets_;
// No copying allowed
BlockBasedFilterBlockBuilder(const BlockBasedFilterBlockBuilder&);
void operator=(const BlockBasedFilterBlockBuilder&);
};
// A FilterBlockReader is used to parse filter from SST table.
// KeyMayMatch and PrefixMayMatch would trigger filter checking
class BlockBasedFilterBlockReader : public FilterBlockReader {
public:
// REQUIRES: "contents" and *policy must stay live while *this is live.
BlockBasedFilterBlockReader(const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
const Slice& contents,
bool delete_contents_after_use = false);
virtual bool IsBlockBased() override { return true; }
virtual bool KeyMayMatch(const Slice& key,
uint64_t block_offset = kNotValid) override;
virtual bool PrefixMayMatch(const Slice& prefix,
uint64_t block_offset = kNotValid) override;
virtual size_t ApproximateMemoryUsage() const override;
private:
const FilterPolicy* policy_;
const SliceTransform* prefix_extractor_;
bool whole_key_filtering_;
const char* data_; // Pointer to filter data (at block-start)
const char* offset_; // Pointer to beginning of offset array (at block-end)
size_t num_; // Number of entries in offset array
size_t base_lg_; // Encoding parameter (see kFilterBaseLg in .cc file)
std::unique_ptr<const char[]> filter_data;
bool MayMatch(const Slice& entry, uint64_t block_offset);
// No copying allowed
BlockBasedFilterBlockReader(const BlockBasedFilterBlockReader&);
void operator=(const BlockBasedFilterBlockReader&);
};
} // namespace rocksdb

242
table/block_based_filter_block_test.cc Normal file
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@ -0,0 +1,242 @@
// 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.
//
// Copyright (c) 2012 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 "table/block_based_filter_block.h"
#include "rocksdb/filter_policy.h"
#include "util/coding.h"
#include "util/hash.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace rocksdb {
// For testing: emit an array with one hash value per key
class TestHashFilter : public FilterPolicy {
public:
virtual const char* Name() const {
return "TestHashFilter";
}
virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const {
for (int i = 0; i < n; i++) {
uint32_t h = Hash(keys[i].data(), keys[i].size(), 1);
PutFixed32(dst, h);
}
}
virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const {
uint32_t h = Hash(key.data(), key.size(), 1);
for (unsigned int i = 0; i + 4 <= filter.size(); i += 4) {
if (h == DecodeFixed32(filter.data() + i)) {
return true;
}
}
return false;
}
};
class FilterBlockTest {
public:
TestHashFilter policy_;
BlockBasedTableOptions table_options_;
FilterBlockTest() {
table_options_.filter_policy.reset(new TestHashFilter());
}
};
TEST(FilterBlockTest, EmptyBuilder) {
BlockBasedFilterBlockBuilder builder(nullptr, table_options_);
Slice block = builder.Finish();
ASSERT_EQ("\\x00\\x00\\x00\\x00\\x0b", EscapeString(block));
BlockBasedFilterBlockReader reader(nullptr, table_options_, block);
ASSERT_TRUE(reader.KeyMayMatch("foo", 0));
ASSERT_TRUE(reader.KeyMayMatch("foo", 100000));
}
TEST(FilterBlockTest, SingleChunk) {
BlockBasedFilterBlockBuilder builder(nullptr, table_options_);
builder.StartBlock(100);
builder.Add("foo");
builder.Add("bar");
builder.Add("box");
builder.StartBlock(200);
builder.Add("box");
builder.StartBlock(300);
builder.Add("hello");
Slice block = builder.Finish();
BlockBasedFilterBlockReader reader(nullptr, table_options_, block);
ASSERT_TRUE(reader.KeyMayMatch("foo", 100));
ASSERT_TRUE(reader.KeyMayMatch("bar", 100));
ASSERT_TRUE(reader.KeyMayMatch("box", 100));
ASSERT_TRUE(reader.KeyMayMatch("hello", 100));
ASSERT_TRUE(reader.KeyMayMatch("foo", 100));
ASSERT_TRUE(!reader.KeyMayMatch("missing", 100));
ASSERT_TRUE(!reader.KeyMayMatch("other", 100));
}
TEST(FilterBlockTest, MultiChunk) {
BlockBasedFilterBlockBuilder builder(nullptr, table_options_);
// First filter
builder.StartBlock(0);
builder.Add("foo");
builder.StartBlock(2000);
builder.Add("bar");
// Second filter
builder.StartBlock(3100);
builder.Add("box");
// Third filter is empty
// Last filter
builder.StartBlock(9000);
builder.Add("box");
builder.Add("hello");
Slice block = builder.Finish();
BlockBasedFilterBlockReader reader(nullptr, table_options_, block);
// Check first filter
ASSERT_TRUE(reader.KeyMayMatch("foo", 0));
ASSERT_TRUE(reader.KeyMayMatch("bar", 2000));
ASSERT_TRUE(!reader.KeyMayMatch("box", 0));
ASSERT_TRUE(!reader.KeyMayMatch("hello", 0));
// Check second filter
ASSERT_TRUE(reader.KeyMayMatch("box", 3100));
ASSERT_TRUE(!reader.KeyMayMatch("foo", 3100));
ASSERT_TRUE(!reader.KeyMayMatch("bar", 3100));
ASSERT_TRUE(!reader.KeyMayMatch("hello", 3100));
// Check third filter (empty)
ASSERT_TRUE(!reader.KeyMayMatch("foo", 4100));
ASSERT_TRUE(!reader.KeyMayMatch("bar", 4100));
ASSERT_TRUE(!reader.KeyMayMatch("box", 4100));
ASSERT_TRUE(!reader.KeyMayMatch("hello", 4100));
// Check last filter
ASSERT_TRUE(reader.KeyMayMatch("box", 9000));
ASSERT_TRUE(reader.KeyMayMatch("hello", 9000));
ASSERT_TRUE(!reader.KeyMayMatch("foo", 9000));
ASSERT_TRUE(!reader.KeyMayMatch("bar", 9000));
}
// Test for block based filter block
// use new interface in FilterPolicy to create filter builder/reader
class BlockBasedFilterBlockTest {
public:
BlockBasedTableOptions table_options_;
BlockBasedFilterBlockTest() {
table_options_.filter_policy.reset(NewBloomFilterPolicy(10));
}
~BlockBasedFilterBlockTest() {}
};
TEST(BlockBasedFilterBlockTest, BlockBasedEmptyBuilder) {
FilterBlockBuilder* builder = new BlockBasedFilterBlockBuilder(
nullptr, table_options_);
Slice block = builder->Finish();
ASSERT_EQ("\\x00\\x00\\x00\\x00\\x0b", EscapeString(block));
FilterBlockReader* reader = new BlockBasedFilterBlockReader(
nullptr, table_options_, block);
ASSERT_TRUE(reader->KeyMayMatch("foo", 0));
ASSERT_TRUE(reader->KeyMayMatch("foo", 100000));
delete builder;
delete reader;
}
TEST(BlockBasedFilterBlockTest, BlockBasedSingleChunk) {
FilterBlockBuilder* builder = new BlockBasedFilterBlockBuilder(
nullptr, table_options_);
builder->StartBlock(100);
builder->Add("foo");
builder->Add("bar");
builder->Add("box");
builder->StartBlock(200);
builder->Add("box");
builder->StartBlock(300);
builder->Add("hello");
Slice block = builder->Finish();
FilterBlockReader* reader = new BlockBasedFilterBlockReader(
nullptr, table_options_, block);
ASSERT_TRUE(reader->KeyMayMatch("foo", 100));
ASSERT_TRUE(reader->KeyMayMatch("bar", 100));
ASSERT_TRUE(reader->KeyMayMatch("box", 100));
ASSERT_TRUE(reader->KeyMayMatch("hello", 100));
ASSERT_TRUE(reader->KeyMayMatch("foo", 100));
ASSERT_TRUE(!reader->KeyMayMatch("missing", 100));
ASSERT_TRUE(!reader->KeyMayMatch("other", 100));
delete builder;
delete reader;
}
TEST(BlockBasedFilterBlockTest, BlockBasedMultiChunk) {
FilterBlockBuilder* builder = new BlockBasedFilterBlockBuilder(
nullptr, table_options_);
// First filter
builder->StartBlock(0);
builder->Add("foo");
builder->StartBlock(2000);
builder->Add("bar");
// Second filter
builder->StartBlock(3100);
builder->Add("box");
// Third filter is empty
// Last filter
builder->StartBlock(9000);
builder->Add("box");
builder->Add("hello");
Slice block = builder->Finish();
FilterBlockReader* reader = new BlockBasedFilterBlockReader(
nullptr, table_options_, block);
// Check first filter
ASSERT_TRUE(reader->KeyMayMatch("foo", 0));
ASSERT_TRUE(reader->KeyMayMatch("bar", 2000));
ASSERT_TRUE(!reader->KeyMayMatch("box", 0));
ASSERT_TRUE(!reader->KeyMayMatch("hello", 0));
// Check second filter
ASSERT_TRUE(reader->KeyMayMatch("box", 3100));
ASSERT_TRUE(!reader->KeyMayMatch("foo", 3100));
ASSERT_TRUE(!reader->KeyMayMatch("bar", 3100));
ASSERT_TRUE(!reader->KeyMayMatch("hello", 3100));
// Check third filter (empty)
ASSERT_TRUE(!reader->KeyMayMatch("foo", 4100));
ASSERT_TRUE(!reader->KeyMayMatch("bar", 4100));
ASSERT_TRUE(!reader->KeyMayMatch("box", 4100));
ASSERT_TRUE(!reader->KeyMayMatch("hello", 4100));
// Check last filter
ASSERT_TRUE(reader->KeyMayMatch("box", 9000));
ASSERT_TRUE(reader->KeyMayMatch("hello", 9000));
ASSERT_TRUE(!reader->KeyMayMatch("foo", 9000));
ASSERT_TRUE(!reader->KeyMayMatch("bar", 9000));
delete builder;
delete reader;
}
} // namespace rocksdb
int main(int argc, char** argv) { return rocksdb::test::RunAllTests(); }

39
table/block_based_table_builder.cc
View File

@ -31,6 +31,8 @@
#include "table/block_based_table_reader.h"
#include "table/block_builder.h"
#include "table/filter_block.h"
#include "table/block_based_filter_block.h"
#include "table/full_filter_block.h"
#include "table/format.h"
#include "table/meta_blocks.h"
#include "table/table_builder.h"
@ -274,6 +276,21 @@ IndexBuilder* CreateIndexBuilder(IndexType type, const Comparator* comparator,
return nullptr;
}
// Create a index builder based on its type.
FilterBlockBuilder* CreateFilterBlockBuilder(const ImmutableCFOptions& opt,
const BlockBasedTableOptions& table_opt) {
if (table_opt.filter_policy == nullptr) return nullptr;
FilterBitsBuilder* filter_bits_builder =
table_opt.filter_policy->GetFilterBitsBuilder();
if (filter_bits_builder == nullptr) {
return new BlockBasedFilterBlockBuilder(opt.prefix_extractor, table_opt);
} else {
return new FullFilterBlockBuilder(opt.prefix_extractor, table_opt,
filter_bits_builder);
}
}
bool GoodCompressionRatio(size_t compressed_size, size_t raw_size) {
// Check to see if compressed less than 12.5%
return compressed_size < raw_size - (raw_size / 8u);
@ -365,7 +382,6 @@ class BlockBasedTableBuilder::BlockBasedTablePropertiesCollector
std::string val;
PutFixed32(&val, static_cast<uint32_t>(index_type_));
properties->insert({BlockBasedTablePropertyNames::kIndexType, val});
return Status::OK();
}
@ -428,11 +444,7 @@ struct BlockBasedTableBuilder::Rep {
table_options.index_type, &internal_comparator,
&this->internal_prefix_transform)),
compression_type(compression_type),
compression_opts(compression_opts),
filter_block(table_options.filter_policy == nullptr ?
nullptr :
new FilterBlockBuilder(ioptions.prefix_extractor,
table_options, &internal_comparator)),
filter_block(CreateFilterBlockBuilder(ioptions, table_options)),
flush_block_policy(
table_options.flush_block_policy_factory->NewFlushBlockPolicy(
table_options, data_block)) {
@ -497,7 +509,7 @@ void BlockBasedTableBuilder::Add(const Slice& key, const Slice& value) {
}
if (r->filter_block != nullptr) {
r->filter_block->AddKey(ExtractUserKey(key));
r->filter_block->Add(ExtractUserKey(key));
}
r->last_key.assign(key.data(), key.size());
@ -661,10 +673,7 @@ Status BlockBasedTableBuilder::Finish() {
assert(!r->closed);
r->closed = true;
BlockHandle filter_block_handle,
metaindex_block_handle,
index_block_handle;
BlockHandle filter_block_handle, metaindex_block_handle, index_block_handle;
// Write filter block
if (ok() && r->filter_block != nullptr) {
auto filter_contents = r->filter_block->Finish();
@ -703,7 +712,12 @@ Status BlockBasedTableBuilder::Finish() {
if (r->filter_block != nullptr) {
// Add mapping from "<filter_block_prefix>.Name" to location
// of filter data.
std::string key = BlockBasedTable::kFilterBlockPrefix;
std::string key;
if (r->filter_block->IsBlockBased()) {
key = BlockBasedTable::kFilterBlockPrefix;
} else {
key = BlockBasedTable::kFullFilterBlockPrefix;
}
key.append(r->table_options.filter_policy->Name());
meta_index_builder.Add(key, filter_block_handle);
}
@ -807,5 +821,6 @@ uint64_t BlockBasedTableBuilder::FileSize() const {
}
const std::string BlockBasedTable::kFilterBlockPrefix = "filter.";
const std::string BlockBasedTable::kFullFilterBlockPrefix = "fullfilter.";
} // namespace rocksdb

266
table/block_based_table_reader.cc
View File

@ -26,6 +26,8 @@
#include "table/block.h"
#include "table/filter_block.h"
#include "table/block_based_filter_block.h"
#include "table/full_filter_block.h"
#include "table/block_hash_index.h"
#include "table/block_prefix_index.h"
#include "table/format.h"
@ -46,7 +48,6 @@ using std::unique_ptr;
typedef BlockBasedTable::IndexReader IndexReader;
namespace {
// The longest the prefix of the cache key used to identify blocks can be.
// We are using the fact that we know for Posix files the unique ID is three
// varints.
@ -527,11 +528,18 @@ Status BlockBasedTable::Open(const ImmutableCFOptions& ioptions,
// Set filter block
if (rep->filter_policy) {
std::string key = kFilterBlockPrefix;
key.append(rep->filter_policy->Name());
BlockHandle handle;
if (FindMetaBlock(meta_iter.get(), key, &handle).ok()) {
rep->filter.reset(ReadFilter(handle, rep));
// First try reading full_filter, then reading block_based_filter
for (auto filter_block_prefix : { kFullFilterBlockPrefix,
kFilterBlockPrefix }) {
std::string key = filter_block_prefix;
key.append(rep->filter_policy->Name());
BlockHandle handle;
if (FindMetaBlock(meta_iter.get(), key, &handle).ok()) {
rep->filter.reset(ReadFilter(handle, rep,
filter_block_prefix, nullptr));
break;
}
}
}
} else {
@ -741,9 +749,9 @@ Status BlockBasedTable::PutDataBlockToCache(
return s;
}
FilterBlockReader* BlockBasedTable::ReadFilter(const BlockHandle& filter_handle,
BlockBasedTable::Rep* rep,
size_t* filter_size) {
FilterBlockReader* BlockBasedTable::ReadFilter(
const BlockHandle& filter_handle, BlockBasedTable::Rep* rep,
const std::string& filter_block_prefix, size_t* filter_size) {
// TODO: We might want to unify with ReadBlockFromFile() if we start
// requiring checksum verification in Table::Open.
ReadOptions opt;
@ -757,13 +765,25 @@ FilterBlockReader* BlockBasedTable::ReadFilter(const BlockHandle& filter_handle,
*filter_size = block.data.size();
}
return new FilterBlockReader(
rep->ioptions.prefix_extractor, rep->table_options,
block.data, block.heap_allocated);
assert(rep->filter_policy);
if (kFilterBlockPrefix == filter_block_prefix) {
return new BlockBasedFilterBlockReader(rep->ioptions.prefix_extractor,
rep->table_options, block.data, block.heap_allocated);
} else if (kFullFilterBlockPrefix == filter_block_prefix) {
auto filter_bits_reader = rep->filter_policy->
GetFilterBitsReader(block.data);
if (filter_bits_reader != nullptr) {
return new FullFilterBlockReader(rep->ioptions.prefix_extractor,
rep->table_options, block.data, filter_bits_reader,
block.heap_allocated);
}
}
return nullptr;
}
BlockBasedTable::CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
bool no_io) const {
bool no_io) const {
// filter pre-populated
if (rep_->filter != nullptr) {
return {rep_->filter.get(), nullptr /* cache handle */};
@ -777,11 +797,9 @@ BlockBasedTable::CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
// Fetching from the cache
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
auto key = GetCacheKey(
rep_->cache_key_prefix,
rep_->cache_key_prefix_size,
rep_->footer.metaindex_handle(),
cache_key
auto key = GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
rep_->footer.metaindex_handle(),
cache_key
);
Statistics* statistics = rep_->ioptions.statistics;
@ -791,8 +809,8 @@ BlockBasedTable::CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
FilterBlockReader* filter = nullptr;
if (cache_handle != nullptr) {
filter = reinterpret_cast<FilterBlockReader*>(
block_cache->Value(cache_handle));
filter = reinterpret_cast<FilterBlockReader*>(
block_cache->Value(cache_handle));
} else if (no_io) {
// Do not invoke any io.
return CachableEntry<FilterBlockReader>();
@ -803,17 +821,22 @@ BlockBasedTable::CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
auto s = ReadMetaBlock(rep_, &meta, &iter);
if (s.ok()) {
std::string filter_block_key = kFilterBlockPrefix;
filter_block_key.append(rep_->filter_policy->Name());
BlockHandle handle;
if (FindMetaBlock(iter.get(), filter_block_key, &handle).ok()) {
filter = ReadFilter(handle, rep_, &filter_size);
assert(filter);
assert(filter_size > 0);
// First try reading full_filter, then reading block_based_filter
for (auto filter_block_prefix : {kFullFilterBlockPrefix,
kFilterBlockPrefix}) {
std::string filter_block_key = filter_block_prefix;
filter_block_key.append(rep_->filter_policy->Name());
BlockHandle handle;
if (FindMetaBlock(iter.get(), filter_block_key, &handle).ok()) {
filter = ReadFilter(handle, rep_, filter_block_prefix, &filter_size);
cache_handle = block_cache->Insert(
key, filter, filter_size, &DeleteCachedEntry<FilterBlockReader>);
RecordTick(statistics, BLOCK_CACHE_ADD);
if (filter == nullptr) break; // err happen in ReadFilter
assert(filter_size > 0);
cache_handle = block_cache->Insert(
key, filter, filter_size, &DeleteCachedEntry<FilterBlockReader>);
RecordTick(statistics, BLOCK_CACHE_ADD);
break;
}
}
}
}
@ -918,8 +941,8 @@ Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
// create key for block cache
if (block_cache != nullptr) {
key = GetCacheKey(rep->cache_key_prefix,
rep->cache_key_prefix_size, handle, cache_key);
key = GetCacheKey(rep->cache_key_prefix, rep->cache_key_prefix_size,
handle, cache_key);
}
if (block_cache_compressed != nullptr) {
@ -1039,42 +1062,50 @@ bool BlockBasedTable::PrefixMayMatch(const Slice& internal_key) {
// loaded to memory.
ReadOptions no_io_read_options;
no_io_read_options.read_tier = kBlockCacheTier;
unique_ptr<Iterator> iiter(NewIndexIterator(no_io_read_options));
iiter->Seek(internal_prefix);
if (!iiter->Valid()) {
// we're past end of file
// if it's incomplete, it means that we avoided I/O
// and we're not really sure that we're past the end
// of the file
may_match = iiter->status().IsIncomplete();
} else if (ExtractUserKey(iiter->key()).starts_with(
ExtractUserKey(internal_prefix))) {
// we need to check for this subtle case because our only
// guarantee is that "the key is a string >= last key in that data
// block" according to the doc/table_format.txt spec.
//
// Suppose iiter->key() starts with the desired prefix; it is not
// necessarily the case that the corresponding data block will
// contain the prefix, since iiter->key() need not be in the
// block. However, the next data block may contain the prefix, so
// we return true to play it safe.
may_match = true;
} else {
// iiter->key() does NOT start with the desired prefix. Because
// Seek() finds the first key that is >= the seek target, this
// means that iiter->key() > prefix. Thus, any data blocks coming
// after the data block corresponding to iiter->key() cannot
// possibly contain the key. Thus, the corresponding data block
// is the only one which could potentially contain the prefix.
Slice handle_value = iiter->value();
BlockHandle handle;
s = handle.DecodeFrom(&handle_value);
assert(s.ok());
auto filter_entry = GetFilter(true /* no io */);
may_match = filter_entry.value == nullptr ||
filter_entry.value->PrefixMayMatch(handle.offset(), prefix);
filter_entry.Release(rep_->table_options.block_cache.get());
// First, try check with full filter
auto filter_entry = GetFilter(true /* no io */);
FilterBlockReader* filter = filter_entry.value;
if (filter != nullptr && !filter->IsBlockBased()) {
may_match = filter->PrefixMayMatch(prefix);
}
// Then, try find it within each block
if (may_match) {
unique_ptr<Iterator> iiter(NewIndexIterator(no_io_read_options));
iiter->Seek(internal_prefix);
if (!iiter->Valid()) {
// we're past end of file
// if it's incomplete, it means that we avoided I/O
// and we're not really sure that we're past the end
// of the file
may_match = iiter->status().IsIncomplete();
} else if (ExtractUserKey(iiter->key()).starts_with(
ExtractUserKey(internal_prefix))) {
// we need to check for this subtle case because our only
// guarantee is that "the key is a string >= last key in that data
// block" according to the doc/table_format.txt spec.
//
// Suppose iiter->key() starts with the desired prefix; it is not
// necessarily the case that the corresponding data block will
// contain the prefix, since iiter->key() need not be in the
// block. However, the next data block may contain the prefix, so
// we return true to play it safe.
may_match = true;
} else if (filter != nullptr && filter->IsBlockBased()) {
// iiter->key() does NOT start with the desired prefix. Because
// Seek() finds the first key that is >= the seek target, this
// means that iiter->key() > prefix. Thus, any data blocks coming
// after the data block corresponding to iiter->key() cannot
// possibly contain the key. Thus, the corresponding data block
// is the only on could potentially contain the prefix.
Slice handle_value = iiter->value();
BlockHandle handle;
s = handle.DecodeFrom(&handle_value);
assert(s.ok());
may_match = filter->PrefixMayMatch(prefix, handle.offset());
}
}
Statistics* statistics = rep_->ioptions.statistics;
@ -1083,6 +1114,7 @@ bool BlockBasedTable::PrefixMayMatch(const Slice& internal_key) {
RecordTick(statistics, BLOOM_FILTER_PREFIX_USEFUL);
}
filter_entry.Release(rep_->table_options.block_cache.get());
return may_match;
}
@ -1098,64 +1130,72 @@ Status BlockBasedTable::Get(
const Slice& v),
void (*mark_key_may_exist_handler)(void* handle_context)) {
Status s;
BlockIter iiter;
NewIndexIterator(read_options, &iiter);
auto filter_entry = GetFilter(read_options.read_tier == kBlockCacheTier);
FilterBlockReader* filter = filter_entry.value;
bool done = false;
for (iiter.Seek(key); iiter.Valid() && !done; iiter.Next()) {
Slice handle_value = iiter.value();
BlockHandle handle;
bool may_not_exist_in_filter =
filter != nullptr && handle.DecodeFrom(&handle_value).ok() &&
!filter->KeyMayMatch(handle.offset(), ExtractUserKey(key));
// First check the full filter
// If full filter not useful, Then go into each block
if (filter != nullptr && !filter->IsBlockBased()
&& !filter->KeyMayMatch(ExtractUserKey(key))) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
} else {
BlockIter iiter;
NewIndexIterator(read_options, &iiter);
if (may_not_exist_in_filter) {
// Not found
// TODO: think about interaction with Merge. If a user key cannot
// cross one data block, we should be fine.
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
break;
} else {
BlockIter biter;
NewDataBlockIterator(rep_, read_options, iiter.value(), &biter);
bool done = false;
for (iiter.Seek(key); iiter.Valid() && !done; iiter.Next()) {
Slice handle_value = iiter.value();
if (read_options.read_tier && biter.status().IsIncomplete()) {
// couldn't get block from block_cache
// Update Saver.state to Found because we are only looking for whether
// we can guarantee the key is not there when "no_io" is set
(*mark_key_may_exist_handler)(handle_context);
BlockHandle handle;
bool not_exist_in_filter =
filter != nullptr && filter->IsBlockBased() == true &&
handle.DecodeFrom(&handle_value).ok() &&
!filter->KeyMayMatch(ExtractUserKey(key), handle.offset());
if (not_exist_in_filter) {
// Not found
// TODO: think about interaction with Merge. If a user key cannot
// cross one data block, we should be fine.
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
break;
}
if (!biter.status().ok()) {
s = biter.status();
break;
}
} else {
BlockIter biter;
NewDataBlockIterator(rep_, read_options, iiter.value(), &biter);
// Call the *saver function on each entry/block until it returns false
for (biter.Seek(key); biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (!(*result_handler)(handle_context, parsed_key,
biter.value())) {
done = true;
if (read_options.read_tier && biter.status().IsIncomplete()) {
// couldn't get block from block_cache
// Update Saver.state to Found because we are only looking for whether
// we can guarantee the key is not there when "no_io" is set
(*mark_key_may_exist_handler)(handle_context);
break;
}
if (!biter.status().ok()) {
s = biter.status();
break;
}
// Call the *saver function on each entry/block until it returns false
for (biter.Seek(key); biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (!(*result_handler)(handle_context, parsed_key,
biter.value())) {
done = true;
break;
}
}
s = biter.status();
}
s = biter.status();
}
if (s.ok()) {
s = iiter.status();
}
}
filter_entry.Release(rep_->table_options.block_cache.get());
if (s.ok()) {
s = iiter.status();
}
return s;
}
@ -1175,8 +1215,8 @@ bool BlockBasedTable::TEST_KeyInCache(const ReadOptions& options,
char cache_key_storage[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
Slice cache_key =
GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size, handle,
cache_key_storage);
GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
handle, cache_key_storage);
Slice ckey;
s = GetDataBlockFromCache(cache_key, ckey, block_cache, nullptr, nullptr,

7
table/block_based_table_reader.h
View File

@ -28,6 +28,8 @@ class BlockIter;
class BlockHandle;
class Cache;
class FilterBlockReader;
class BlockBasedFilterBlockReader;
class FullFilterBlockReader;
class Footer;
class InternalKeyComparator;
class Iterator;
@ -47,6 +49,7 @@ using std::unique_ptr;
class BlockBasedTable : public TableReader {
public:
static const std::string kFilterBlockPrefix;
static const std::string kFullFilterBlockPrefix;
// Attempt to open the table that is stored in bytes [0..file_size)
// of "file", and read the metadata entries necessary to allow
@ -184,7 +187,9 @@ class BlockBasedTable : public TableReader {
// Create the filter from the filter block.
static FilterBlockReader* ReadFilter(const BlockHandle& filter_handle,
Rep* rep, size_t* filter_size = nullptr);
Rep* rep,
const std::string& filter_block_prefix,
size_t* filter_size = nullptr);
static void SetupCacheKeyPrefix(Rep* rep);

82
table/filter_block.h
View File

@ -10,86 +10,70 @@
// A filter block is stored near the end of a Table file. It contains
// filters (e.g., bloom filters) for all data blocks in the table combined
// into a single filter block.
//
// It is a base class for BlockBasedFilter and FullFilter.
// These two are both used in BlockBasedTable. The first one contain filter
// For a part of keys in sst file, the second contain filter for all keys
// in sst file.
#pragma once
#include <memory>
#include <stddef.h>
#include <stdint.h>
#include <string>
#include <vector>
#include "rocksdb/options.h"
#include "rocksdb/slice.h"
#include "rocksdb/slice_transform.h"
#include "rocksdb/table.h"
#include "util/hash.h"
namespace rocksdb {
class FilterPolicy;
const uint64_t kNotValid = ULLONG_MAX;
// A FilterBlockBuilder is used to construct all of the filters for a
// particular Table. It generates a single string which is stored as
// a special block in the Table.
//
// The sequence of calls to FilterBlockBuilder must match the regexp:
// (StartBlock AddKey*)* Finish
// (StartBlock Add*)* Finish
//
// BlockBased/Full FilterBlock would be called in the same way.
class FilterBlockBuilder {
public:
explicit FilterBlockBuilder(const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
const Comparator* internal_comparator);
explicit FilterBlockBuilder() {}
virtual ~FilterBlockBuilder() {}
void StartBlock(uint64_t block_offset);
void AddKey(const Slice& key);
Slice Finish();
virtual bool IsBlockBased() = 0; // If is blockbased filter
virtual void StartBlock(uint64_t block_offset) = 0; // Start new block filter
virtual void Add(const Slice& key) = 0; // Add a key to current filter
virtual Slice Finish() = 0; // Generate Filter
private:
bool SamePrefix(const Slice &key1, const Slice &key2) const;
void GenerateFilter();
// important: all of these might point to invalid addresses
// at the time of destruction of this filter block. destructor
// should NOT dereference them.
const FilterPolicy* policy_;
const SliceTransform* prefix_extractor_;
bool whole_key_filtering_;
const Comparator* comparator_;
std::string entries_; // Flattened entry contents
std::vector<size_t> start_; // Starting index in entries_ of each entry
std::string result_; // Filter data computed so far
std::vector<Slice> tmp_entries_; // policy_->CreateFilter() argument
std::vector<uint32_t> filter_offsets_;
// No copying allowed
FilterBlockBuilder(const FilterBlockBuilder&);
void operator=(const FilterBlockBuilder&);
};
// A FilterBlockReader is used to parse filter from SST table.
// KeyMayMatch and PrefixMayMatch would trigger filter checking
//
// BlockBased/Full FilterBlock would be called in the same way.
class FilterBlockReader {
public:
// REQUIRES: "contents" and *policy must stay live while *this is live.
FilterBlockReader(
const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
const Slice& contents,
bool delete_contents_after_use = false);
bool KeyMayMatch(uint64_t block_offset, const Slice& key);
bool PrefixMayMatch(uint64_t block_offset, const Slice& prefix);
size_t ApproximateMemoryUsage() const;
explicit FilterBlockReader() {}
virtual ~FilterBlockReader() {}
virtual bool IsBlockBased() = 0; // If is blockbased filter
virtual bool KeyMayMatch(const Slice& key,
uint64_t block_offset = kNotValid) = 0;
virtual bool PrefixMayMatch(const Slice& prefix,
uint64_t block_offset = kNotValid) = 0;
virtual size_t ApproximateMemoryUsage() const = 0;
private:
const FilterPolicy* policy_;
const SliceTransform* prefix_extractor_;
bool whole_key_filtering_;
const char* data_; // Pointer to filter data (at block-start)
const char* offset_; // Pointer to beginning of offset array (at block-end)
size_t num_; // Number of entries in offset array
size_t base_lg_; // Encoding parameter (see kFilterBaseLg in .cc file)
std::unique_ptr<const char[]> filter_data;
bool MayMatch(uint64_t block_offset, const Slice& entry);
// No copying allowed
FilterBlockReader(const FilterBlockReader&);
void operator=(const FilterBlockReader&);
};
}
} // namespace rocksdb

139
table/filter_block_test.cc
View File

@ -1,139 +0,0 @@
// 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.
//
// Copyright (c) 2012 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 "table/filter_block.h"
#include "rocksdb/filter_policy.h"
#include "util/coding.h"
#include "util/hash.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace rocksdb {
// For testing: emit an array with one hash value per key
class TestHashFilter : public FilterPolicy {
public:
virtual const char* Name() const {
return "TestHashFilter";
}
virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const {
for (int i = 0; i < n; i++) {
uint32_t h = Hash(keys[i].data(), keys[i].size(), 1);
PutFixed32(dst, h);
}
}
virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const {
uint32_t h = Hash(key.data(), key.size(), 1);
for (unsigned int i = 0; i + 4 <= filter.size(); i += 4) {
if (h == DecodeFixed32(filter.data() + i)) {
return true;
}
}
return false;
}
};
class FilterBlockTest {
public:
const Comparator* comparator_;
BlockBasedTableOptions table_options_;
FilterBlockTest()
: comparator_(BytewiseComparator()) {
table_options_.filter_policy.reset(new TestHashFilter());
}
};
TEST(FilterBlockTest, EmptyBuilder) {
FilterBlockBuilder builder(nullptr, table_options_, comparator_);
Slice block = builder.Finish();
ASSERT_EQ("\\x00\\x00\\x00\\x00\\x0b", EscapeString(block));
FilterBlockReader reader(nullptr, table_options_, block);
ASSERT_TRUE(reader.KeyMayMatch(0, "foo"));
ASSERT_TRUE(reader.KeyMayMatch(100000, "foo"));
}
TEST(FilterBlockTest, SingleChunk) {
FilterBlockBuilder builder(nullptr, table_options_, comparator_);
builder.StartBlock(100);
builder.AddKey("foo");
builder.AddKey("bar");
builder.AddKey("box");
builder.StartBlock(200);
builder.AddKey("box");
builder.StartBlock(300);
builder.AddKey("hello");
Slice block = builder.Finish();
FilterBlockReader reader(nullptr, table_options_, block);
ASSERT_TRUE(reader.KeyMayMatch(100, "foo"));
ASSERT_TRUE(reader.KeyMayMatch(100, "bar"));
ASSERT_TRUE(reader.KeyMayMatch(100, "box"));
ASSERT_TRUE(reader.KeyMayMatch(100, "hello"));
ASSERT_TRUE(reader.KeyMayMatch(100, "foo"));
ASSERT_TRUE(! reader.KeyMayMatch(100, "missing"));
ASSERT_TRUE(! reader.KeyMayMatch(100, "other"));
}
TEST(FilterBlockTest, MultiChunk) {
FilterBlockBuilder builder(nullptr, table_options_, comparator_);
// First filter
builder.StartBlock(0);
builder.AddKey("foo");
builder.StartBlock(2000);
builder.AddKey("bar");
// Second filter
builder.StartBlock(3100);
builder.AddKey("box");
// Third filter is empty
// Last filter
builder.StartBlock(9000);
builder.AddKey("box");
builder.AddKey("hello");
Slice block = builder.Finish();
FilterBlockReader reader(nullptr, table_options_, block);
// Check first filter
ASSERT_TRUE(reader.KeyMayMatch(0, "foo"));
ASSERT_TRUE(reader.KeyMayMatch(2000, "bar"));
ASSERT_TRUE(! reader.KeyMayMatch(0, "box"));
ASSERT_TRUE(! reader.KeyMayMatch(0, "hello"));
// Check second filter
ASSERT_TRUE(reader.KeyMayMatch(3100, "box"));
ASSERT_TRUE(! reader.KeyMayMatch(3100, "foo"));
ASSERT_TRUE(! reader.KeyMayMatch(3100, "bar"));
ASSERT_TRUE(! reader.KeyMayMatch(3100, "hello"));
// Check third filter (empty)
ASSERT_TRUE(! reader.KeyMayMatch(4100, "foo"));
ASSERT_TRUE(! reader.KeyMayMatch(4100, "bar"));
ASSERT_TRUE(! reader.KeyMayMatch(4100, "box"));
ASSERT_TRUE(! reader.KeyMayMatch(4100, "hello"));
// Check last filter
ASSERT_TRUE(reader.KeyMayMatch(9000, "box"));
ASSERT_TRUE(reader.KeyMayMatch(9000, "hello"));
ASSERT_TRUE(! reader.KeyMayMatch(9000, "foo"));
ASSERT_TRUE(! reader.KeyMayMatch(9000, "bar"));
}
} // namespace rocksdb
int main(int argc, char** argv) {
return rocksdb::test::RunAllTests();
}

99
table/full_filter_block.cc Normal file
View File

@ -0,0 +1,99 @@
// Copyright (c) 2014, 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 "table/full_filter_block.h"
#include "rocksdb/filter_policy.h"
#include "port/port.h"
#include "util/coding.h"
namespace rocksdb {
FullFilterBlockBuilder::FullFilterBlockBuilder(
const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
FilterBitsBuilder* filter_bits_builder)
: prefix_extractor_(prefix_extractor),
whole_key_filtering_(table_opt.whole_key_filtering),
num_added_(0) {
assert(filter_bits_builder != nullptr);
filter_bits_builder_.reset(filter_bits_builder);
}
void FullFilterBlockBuilder::Add(const Slice& key) {
if (whole_key_filtering_) {
AddKey(key);
}
if (prefix_extractor_ && prefix_extractor_->InDomain(key)) {
AddPrefix(key);
}
}
// Add key to filter if needed
inline void FullFilterBlockBuilder::AddKey(const Slice& key) {
filter_bits_builder_->AddKey(key);
num_added_++;
}
// Add prefix to filter if needed
inline void FullFilterBlockBuilder::AddPrefix(const Slice& key) {
Slice prefix = prefix_extractor_->Transform(key);
filter_bits_builder_->AddKey(prefix);
num_added_++;
}
Slice FullFilterBlockBuilder::Finish() {
if (num_added_ != 0) {
num_added_ = 0;
return filter_bits_builder_->Finish(&filter_data);
}
return Slice();
}
FullFilterBlockReader::FullFilterBlockReader(
const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
const Slice& contents,
FilterBitsReader* filter_bits_reader, bool delete_contents_after_use)
: prefix_extractor_(prefix_extractor),
whole_key_filtering_(table_opt.whole_key_filtering),
contents_(contents) {
assert(filter_bits_reader != nullptr);
filter_bits_reader_.reset(filter_bits_reader);
if (delete_contents_after_use) {
filter_data.reset(contents.data());
}
}
bool FullFilterBlockReader::KeyMayMatch(const Slice& key,
uint64_t block_offset) {
assert(block_offset == kNotValid);
if (!whole_key_filtering_) {
return true;
}
return MayMatch(key);
}
bool FullFilterBlockReader::PrefixMayMatch(const Slice& prefix,
uint64_t block_offset) {
assert(block_offset == kNotValid);
if (!prefix_extractor_) {
return true;
}
return MayMatch(prefix);
}
bool FullFilterBlockReader::MayMatch(const Slice& entry) {
if (contents_.size() != 0) {
return filter_bits_reader_->MayMatch(entry);
}
return true; // remain the same with block_based filter
}
size_t FullFilterBlockReader::ApproximateMemoryUsage() const {
return contents_.size();
}
} // namespace rocksdb

107
table/full_filter_block.h Normal file
View File

@ -0,0 +1,107 @@
// Copyright (c) 2014, 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.
#pragma once
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <string>
#include <vector>
#include "rocksdb/options.h"
#include "rocksdb/slice.h"
#include "rocksdb/slice_transform.h"
#include "db/dbformat.h"
#include "util/hash.h"
#include "table/filter_block.h"
namespace rocksdb {
class FilterPolicy;
class FilterBitsBuilder;
class FilterBitsReader;
// A FullFilterBlockBuilder is used to construct a full filter for a
// particular Table. It generates a single string which is stored as
// a special block in the Table.
// The format of full filter block is:
// +----------------------------------------------------------------+
// | full filter for all keys in sst file |
// +----------------------------------------------------------------+
// The full filter can be very large. At the end of it, we put
// num_probes: how many hash functions are used in bloom filter
//
class FullFilterBlockBuilder : public FilterBlockBuilder {
public:
explicit FullFilterBlockBuilder(const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
FilterBitsBuilder* filter_bits_builder);
// bits_builder is created in filter_policy, it should be passed in here
// directly. and be deleted here
~FullFilterBlockBuilder() {}
virtual bool IsBlockBased() override { return false; }
virtual void StartBlock(uint64_t block_offset) override {}
virtual void Add(const Slice& key) override;
virtual Slice Finish() override;
private:
// important: all of these might point to invalid addresses
// at the time of destruction of this filter block. destructor
// should NOT dereference them.
const SliceTransform* prefix_extractor_;
bool whole_key_filtering_;
uint32_t num_added_;
std::unique_ptr<FilterBitsBuilder> filter_bits_builder_;
std::unique_ptr<const char[]> filter_data;
void AddKey(const Slice& key);
void AddPrefix(const Slice& key);
// No copying allowed
FullFilterBlockBuilder(const FullFilterBlockBuilder&);
void operator=(const FullFilterBlockBuilder&);
};
// A FilterBlockReader is used to parse filter from SST table.
// KeyMayMatch and PrefixMayMatch would trigger filter checking
class FullFilterBlockReader : public FilterBlockReader {
public:
// REQUIRES: "contents" and filter_bits_reader must stay live
// while *this is live.
explicit FullFilterBlockReader(const SliceTransform* prefix_extractor,
const BlockBasedTableOptions& table_opt,
const Slice& contents,
FilterBitsReader* filter_bits_reader,
bool delete_contents_after_use = false);
// bits_reader is created in filter_policy, it should be passed in here
// directly. and be deleted here
~FullFilterBlockReader() {}
virtual bool IsBlockBased() override { return false; }
virtual bool KeyMayMatch(const Slice& key,
uint64_t block_offset = kNotValid) override;
virtual bool PrefixMayMatch(const Slice& prefix,
uint64_t block_offset = kNotValid) override;
virtual size_t ApproximateMemoryUsage() const override;
private:
const SliceTransform* prefix_extractor_;
bool whole_key_filtering_;
std::unique_ptr<FilterBitsReader> filter_bits_reader_;
Slice contents_;
std::unique_ptr<const char[]> filter_data;
bool MayMatch(const Slice& entry);
// No copying allowed
FullFilterBlockReader(const FullFilterBlockReader&);
void operator=(const FullFilterBlockReader&);
};
} // namespace rocksdb

181
table/full_filter_block_test.cc Normal file
View File

@ -0,0 +1,181 @@
// Copyright (c) 2014, 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 "table/full_filter_block.h"
#include "rocksdb/filter_policy.h"
#include "util/coding.h"
#include "util/hash.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace rocksdb {
class TestFilterBitsBuilder : public FilterBitsBuilder {
public:
explicit TestFilterBitsBuilder() {}
// Add Key to filter
virtual void AddKey(const Slice& key) override {
hash_entries_.push_back(Hash(key.data(), key.size(), 1));
}
// Generate the filter using the keys that are added
virtual Slice Finish(std::unique_ptr<const char[]>* buf) override {
uint32_t len = hash_entries_.size() * 4;
char* data = new char[len];
for (size_t i = 0; i < hash_entries_.size(); i++) {
EncodeFixed32(data + i * 4, hash_entries_[i]);
}
buf->reset(data);
return Slice(data, len);
}
private:
std::vector<uint32_t> hash_entries_;
};
class TestFilterBitsReader : public FilterBitsReader {
public:
explicit TestFilterBitsReader(const Slice& contents)
: data_(contents.data()), len_(contents.size()) {}
virtual bool MayMatch(const Slice& entry) override {
uint32_t h = Hash(entry.data(), entry.size(), 1);
for (size_t i = 0; i + 4 <= len_; i += 4) {
if (h == DecodeFixed32(data_ + i)) {
return true;
}
}
return false;
}
private:
const char* data_;
uint32_t len_;
};
class TestHashFilter : public FilterPolicy {
public:
virtual const char* Name() const {
return "TestHashFilter";
}
virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const {
for (int i = 0; i < n; i++) {
uint32_t h = Hash(keys[i].data(), keys[i].size(), 1);
PutFixed32(dst, h);
}
}
virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const {
uint32_t h = Hash(key.data(), key.size(), 1);
for (unsigned int i = 0; i + 4 <= filter.size(); i += 4) {
if (h == DecodeFixed32(filter.data() + i)) {
return true;
}
}
return false;
}
virtual FilterBitsBuilder* GetFilterBitsBuilder() const override {
return new TestFilterBitsBuilder();
}
virtual FilterBitsReader* GetFilterBitsReader(const Slice& contents)
const override {
return new TestFilterBitsReader(contents);
}
};
class PluginFullFilterBlockTest {
public:
BlockBasedTableOptions table_options_;
PluginFullFilterBlockTest() {
table_options_.filter_policy.reset(new TestHashFilter());
}
};
TEST(PluginFullFilterBlockTest, PluginEmptyBuilder) {
FullFilterBlockBuilder builder(nullptr, table_options_,
table_options_.filter_policy->GetFilterBitsBuilder());
Slice block = builder.Finish();
ASSERT_EQ("", EscapeString(block));
FullFilterBlockReader reader(nullptr, table_options_, block,
table_options_.filter_policy->GetFilterBitsReader(block));
// Remain same symantic with blockbased filter
ASSERT_TRUE(reader.KeyMayMatch("foo"));
}
TEST(PluginFullFilterBlockTest, PluginSingleChunk) {
FullFilterBlockBuilder builder(nullptr, table_options_,
table_options_.filter_policy->GetFilterBitsBuilder());
builder.Add("foo");
builder.Add("bar");
builder.Add("box");
builder.Add("box");
builder.Add("hello");
Slice block = builder.Finish();
FullFilterBlockReader reader(nullptr, table_options_, block,
table_options_.filter_policy->GetFilterBitsReader(block));
ASSERT_TRUE(reader.KeyMayMatch("foo"));
ASSERT_TRUE(reader.KeyMayMatch("bar"));
ASSERT_TRUE(reader.KeyMayMatch("box"));
ASSERT_TRUE(reader.KeyMayMatch("hello"));
ASSERT_TRUE(reader.KeyMayMatch("foo"));
ASSERT_TRUE(!reader.KeyMayMatch("missing"));
ASSERT_TRUE(!reader.KeyMayMatch("other"));
}
class FullFilterBlockTest {
public:
BlockBasedTableOptions table_options_;
FullFilterBlockTest() {
table_options_.filter_policy.reset(NewBloomFilterPolicy(10, false));
}
~FullFilterBlockTest() {}
};
TEST(FullFilterBlockTest, EmptyBuilder) {
FullFilterBlockBuilder builder(nullptr, table_options_,
table_options_.filter_policy->GetFilterBitsBuilder());
Slice block = builder.Finish();
ASSERT_EQ("", EscapeString(block));
FullFilterBlockReader reader(nullptr, table_options_, block,
table_options_.filter_policy->GetFilterBitsReader(block));
// Remain same symantic with blockbased filter
ASSERT_TRUE(reader.KeyMayMatch("foo"));
}
TEST(FullFilterBlockTest, SingleChunk) {
FullFilterBlockBuilder builder(nullptr, table_options_,
table_options_.filter_policy->GetFilterBitsBuilder());
builder.Add("foo");
builder.Add("bar");
builder.Add("box");
builder.Add("box");
builder.Add("hello");
Slice block = builder.Finish();
FullFilterBlockReader reader(nullptr, table_options_, block,
table_options_.filter_policy->GetFilterBitsReader(block));
ASSERT_TRUE(reader.KeyMayMatch("foo"));
ASSERT_TRUE(reader.KeyMayMatch("bar"));
ASSERT_TRUE(reader.KeyMayMatch("box"));
ASSERT_TRUE(reader.KeyMayMatch("hello"));
ASSERT_TRUE(reader.KeyMayMatch("foo"));
ASSERT_TRUE(!reader.KeyMayMatch("missing"));
ASSERT_TRUE(!reader.KeyMayMatch("other"));
}
} // namespace rocksdb
int main(int argc, char** argv) { return rocksdb::test::RunAllTests(); }

1
table/plain_table_builder.cc
View File

@ -20,7 +20,6 @@
#include "table/block_builder.h"
#include "table/bloom_block.h"
#include "table/plain_table_index.h"
#include "table/filter_block.h"
#include "table/format.h"
#include "table/meta_blocks.h"
#include "util/coding.h"

1
table/plain_table_reader.cc
View File

@ -20,7 +20,6 @@
#include "table/block.h"
#include "table/bloom_block.h"
#include "table/filter_block.h"
#include "table/format.h"
#include "table/meta_blocks.h"
#include "table/two_level_iterator.h"

20
tools/db_sanity_test.cc
View File

@ -16,6 +16,7 @@
#include "include/rocksdb/comparator.h"
#include "include/rocksdb/table.h"
#include "include/rocksdb/slice_transform.h"
#include "include/rocksdb/filter_policy.h"
namespace rocksdb {
@ -146,13 +147,30 @@ class SanityTestPlainTableFactory : public SanityTest {
Options options_;
};
class SanityTestBloomFilter : public SanityTest {
public:
explicit SanityTestBloomFilter(const std::string& path)
: SanityTest(path) {
table_options_.filter_policy.reset(NewBloomFilterPolicy(10));
options_.table_factory.reset(NewBlockBasedTableFactory(table_options_));
}
~SanityTestBloomFilter() {}
virtual Options GetOptions() const { return options_; }
virtual std::string Name() const { return "BloomFilter"; }
private:
Options options_;
BlockBasedTableOptions table_options_;
};
namespace {
bool RunSanityTests(const std::string& command, const std::string& path) {
std::vector<SanityTest*> sanity_tests = {
new SanityTestBasic(path),
new SanityTestSpecialComparator(path),
new SanityTestZlibCompression(path),
new SanityTestPlainTableFactory(path)};
new SanityTestPlainTableFactory(path),
new SanityTestBloomFilter(path)};
if (command == "create") {
fprintf(stderr, "Creating...\n");

9
tools/db_stress.cc
View File

@ -209,6 +209,9 @@ static const bool FLAGS_reopen_dummy __attribute__((unused)) =
DEFINE_int32(bloom_bits, 10, "Bloom filter bits per key. "
"Negative means use default settings.");
DEFINE_bool(use_block_based_filter, false, "use block based filter"
"instead of full filter for block based table");
DEFINE_string(db, "", "Use the db with the following name.");
DEFINE_bool(verify_checksum, false,
@ -757,8 +760,10 @@ class StressTest {
? NewLRUCache(FLAGS_compressed_cache_size)
: nullptr),
filter_policy_(FLAGS_bloom_bits >= 0
? NewBloomFilterPolicy(FLAGS_bloom_bits)
: nullptr),
? FLAGS_use_block_based_filter
? NewBloomFilterPolicy(FLAGS_bloom_bits, true)
: NewBloomFilterPolicy(FLAGS_bloom_bits, false)
: nullptr),
db_(nullptr),
new_column_family_name_(1),
num_times_reopened_(0) {

309
util/bloom.cc
View File

@ -1,4 +1,4 @@
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// Copyright (c) 2014, 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.
@ -10,42 +10,266 @@
#include "rocksdb/filter_policy.h"
#include "rocksdb/slice.h"
#include "table/block_based_filter_block.h"
#include "table/full_filter_block.h"
#include "util/hash.h"
#include "util/coding.h"
namespace rocksdb {
namespace {
class BlockBasedFilterBlockBuilder;
class FullFilterBlockBuilder;
namespace {
class FullFilterBitsBuilder : public FilterBitsBuilder {
public:
explicit FullFilterBitsBuilder(const size_t bits_per_key,
const size_t num_probes)
: bits_per_key_(bits_per_key),
num_probes_(num_probes) {
assert(bits_per_key_);
}
~FullFilterBitsBuilder() {}
virtual void AddKey(const Slice& key) override {
uint32_t hash = BloomHash(key);
if (hash_entries_.size() == 0 || hash != hash_entries_.back()) {
hash_entries_.push_back(hash);
}
}
// Create a filter that for hashes [0, n-1], the filter is allocated here
// When creating filter, it is ensured that
// total_bits = num_lines * CACHE_LINE_SIZE * 8
// dst len is >= 5, 1 for num_probes, 4 for num_lines
// Then total_bits = (len - 5) * 8, and cache_line_size could be calulated
// +----------------------------------------------------------------+
// | filter data with length total_bits/8 |
// +----------------------------------------------------------------+
// | |
// | ... |
// | |
// +----------------------------------------------------------------+
// | ... | num_probes : 1 byte | num_lines : 4 bytes |
// +----------------------------------------------------------------+
virtual Slice Finish(std::unique_ptr<const char[]>* buf) override {
char* data = nullptr;
uint32_t total_bits, num_lines;
data = ReserveSpace(hash_entries_.size(), &total_bits, &num_lines);
assert(data);
if (total_bits != 0 && num_lines != 0) {
for (auto h : hash_entries_) {
AddHash(h, data, num_lines, total_bits);
}
}
data[total_bits/8] = static_cast<char>(num_probes_);
EncodeFixed32(data + total_bits/8 + 1, static_cast<uint32_t>(num_lines));
buf->reset(data);
hash_entries_.clear();
return Slice(data, total_bits / 8 + 5);
}
class BloomFilterPolicy : public FilterPolicy {
private:
size_t bits_per_key_;
size_t k_;
uint32_t (*hash_func_)(const Slice& key);
size_t num_probes_;
std::vector<uint32_t> hash_entries_;
void initialize() {
// We intentionally round down to reduce probing cost a little bit
k_ = static_cast<size_t>(bits_per_key_ * 0.69); // 0.69 =~ ln(2)
if (k_ < 1) k_ = 1;
if (k_ > 30) k_ = 30;
// Get totalbits that optimized for cpu cache line
uint32_t GetTotalBitsForLocality(uint32_t total_bits);
// Reserve space for new filter
char* ReserveSpace(const int num_entry, uint32_t* total_bits,
uint32_t* num_lines);
// Assuming single threaded access to this function.
void AddHash(uint32_t h, char* data, uint32_t num_lines,
uint32_t total_bits);
// No Copy allowed
FullFilterBitsBuilder(const FullFilterBitsBuilder&);
void operator=(const FullFilterBitsBuilder&);
};
uint32_t FullFilterBitsBuilder::GetTotalBitsForLocality(uint32_t total_bits) {
uint32_t num_lines =
(total_bits + CACHE_LINE_SIZE * 8 - 1) / (CACHE_LINE_SIZE * 8);
// Make num_lines an odd number to make sure more bits are involved
// when determining which block.
if (num_lines % 2 == 0) {
num_lines++;
}
return num_lines * (CACHE_LINE_SIZE * 8);
}
char* FullFilterBitsBuilder::ReserveSpace(const int num_entry,
uint32_t* total_bits, uint32_t* num_lines) {
assert(bits_per_key_);
char* data = nullptr;
if (num_entry != 0) {
uint32_t total_bits_tmp = num_entry * bits_per_key_;
*total_bits = GetTotalBitsForLocality(total_bits_tmp);
*num_lines = *total_bits / (CACHE_LINE_SIZE * 8);
assert(*total_bits > 0 && *total_bits % 8 == 0);
} else {
// filter is empty, just leave space for metadata
*total_bits = 0;
*num_lines = 0;
}
// Reserve space for Filter
uint32_t sz = *total_bits / 8;
sz += 5; // 4 bytes for num_lines, 1 byte for num_probes
data = new char[sz];
memset(data, 0, sz);
return data;
}
inline void FullFilterBitsBuilder::AddHash(uint32_t h, char* data,
uint32_t num_lines, uint32_t total_bits) {
assert(num_lines > 0 && total_bits > 0);
const uint32_t delta = (h >> 17) | (h << 15); // Rotate right 17 bits
uint32_t b = (h % num_lines) * (CACHE_LINE_SIZE * 8);
for (uint32_t i = 0; i < num_probes_; ++i) {
// Since CACHE_LINE_SIZE is defined as 2^n, this line will be optimized
// to a simple operation by compiler.
const uint32_t bitpos = b + (h % (CACHE_LINE_SIZE * 8));
data[bitpos / 8] |= (1 << (bitpos % 8));
h += delta;
}
}
class FullFilterBitsReader : public FilterBitsReader {
public:
explicit BloomFilterPolicy(int bits_per_key,
uint32_t (*hash_func)(const Slice& key))
: bits_per_key_(bits_per_key), hash_func_(hash_func) {
initialize();
explicit FullFilterBitsReader(const Slice& contents)
: data_(const_cast<char*>(contents.data())),
data_len_(contents.size()),
num_probes_(0), num_lines_(0) {
assert(data_);
GetFilterMeta(contents, &num_probes_, &num_lines_);
// Sanitize broken parameter
if (num_lines_ != 0 && (data_len_-5) % num_lines_ != 0) {
num_lines_ = 0;
num_probes_ = 0;
}
}
explicit BloomFilterPolicy(int bits_per_key)
: bits_per_key_(bits_per_key) {
hash_func_ = BloomHash;
~FullFilterBitsReader() {}
virtual bool MayMatch(const Slice& entry) override {
if (data_len_ <= 5) { // remain same with original filter
return false;
}
// Other Error params, including a broken filter, regarded as match
if (num_probes_ == 0 || num_lines_ == 0) return true;
uint32_t hash = BloomHash(entry);
return HashMayMatch(hash, Slice(data_, data_len_),
num_probes_, num_lines_);
}
private:
// Filter meta data
char* data_;
uint32_t data_len_;
size_t num_probes_;
uint32_t num_lines_;
// Get num_probes, and num_lines from filter
// If filter format broken, set both to 0.
void GetFilterMeta(const Slice& filter, size_t* num_probes,
uint32_t* num_lines);
// "filter" contains the data appended by a preceding call to
// CreateFilterFromHash() on this class. This method must return true if
// the key was in the list of keys passed to CreateFilter().
// This method may return true or false if the key was not on the
// list, but it should aim to return false with a high probability.
//
// hash: target to be checked
// filter: the whole filter, including meta data bytes
// num_probes: number of probes, read before hand
// num_lines: filter metadata, read before hand
// Before calling this function, need to ensure the input meta data
// is valid.
bool HashMayMatch(const uint32_t& hash, const Slice& filter,
const size_t& num_probes, const uint32_t& num_lines);
// No Copy allowed
FullFilterBitsReader(const FullFilterBitsReader&);
void operator=(const FullFilterBitsReader&);
};
void FullFilterBitsReader::GetFilterMeta(const Slice& filter,
size_t* num_probes, uint32_t* num_lines) {
uint32_t len = filter.size();
if (len <= 5) {
// filter is empty or broken
*num_probes = 0;
*num_lines = 0;
return;
}
*num_probes = filter.data()[len - 5];
*num_lines = DecodeFixed32(filter.data() + len - 4);
}
bool FullFilterBitsReader::HashMayMatch(const uint32_t& hash,
const Slice& filter, const size_t& num_probes,
const uint32_t& num_lines) {
uint32_t len = filter.size();
if (len <= 5) return false; // remain the same with original filter
// It is ensured the params are valid before calling it
assert(num_probes != 0);
assert(num_lines != 0 && (len - 5) % num_lines == 0);
uint32_t cache_line_size = (len - 5) / num_lines;
const char* data = filter.data();
uint32_t h = hash;
const uint32_t delta = (h >> 17) | (h << 15); // Rotate right 17 bits
uint32_t b = (h % num_lines) * (cache_line_size * 8);
for (uint32_t i = 0; i < num_probes; ++i) {
// Since CACHE_LINE_SIZE is defined as 2^n, this line will be optimized
// to a simple and operation by compiler.
const uint32_t bitpos = b + (h % (cache_line_size * 8));
if (((data[bitpos / 8]) & (1 << (bitpos % 8))) == 0) {
return false;
}
h += delta;
}
return true;
}
// An implementation of filter policy
class BloomFilterPolicy : public FilterPolicy {
public:
explicit BloomFilterPolicy(int bits_per_key, bool use_block_based_builder)
: bits_per_key_(bits_per_key), hash_func_(BloomHash),
use_block_based_builder_(use_block_based_builder) {
initialize();
}
virtual const char* Name() const {
~BloomFilterPolicy() {
}
virtual const char* Name() const override {
return "rocksdb.BuiltinBloomFilter";
}
virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const {
virtual void CreateFilter(const Slice* keys, int n,
std::string* dst) const override {
// Compute bloom filter size (in both bits and bytes)
size_t bits = n * bits_per_key_;
@ -58,14 +282,14 @@ class BloomFilterPolicy : public FilterPolicy {
const size_t init_size = dst->size();
dst->resize(init_size + bytes, 0);
dst->push_back(static_cast<char>(k_)); // Remember # of probes in filter
dst->push_back(static_cast<char>(num_probes_)); // Remember # of probes
char* array = &(*dst)[init_size];
for (size_t i = 0; i < (size_t)n; i++) {
// Use double-hashing to generate a sequence of hash values.
// See analysis in [Kirsch,Mitzenmacher 2006].
uint32_t h = hash_func_(keys[i]);
const uint32_t delta = (h >> 17) | (h << 15); // Rotate right 17 bits
for (size_t j = 0; j < k_; j++) {
for (size_t j = 0; j < num_probes_; j++) {
const uint32_t bitpos = h % bits;
array[bitpos/8] |= (1 << (bitpos % 8));
h += delta;
@ -73,7 +297,8 @@ class BloomFilterPolicy : public FilterPolicy {
}
}
virtual bool KeyMayMatch(const Slice& key, const Slice& bloom_filter) const {
virtual bool KeyMayMatch(const Slice& key,
const Slice& bloom_filter) const override {
const size_t len = bloom_filter.size();
if (len < 2) return false;
@ -98,11 +323,43 @@ class BloomFilterPolicy : public FilterPolicy {
}
return true;
}
};
}
const FilterPolicy* NewBloomFilterPolicy(int bits_per_key) {
return new BloomFilterPolicy(bits_per_key);
virtual FilterBitsBuilder* GetFilterBitsBuilder() const override {
if (use_block_based_builder_) {
return nullptr;
}
return new FullFilterBitsBuilder(bits_per_key_, num_probes_);
}
virtual FilterBitsReader* GetFilterBitsReader(const Slice& contents)
const override {
return new FullFilterBitsReader(contents);
}
// If choose to use block based builder
bool UseBlockBasedBuilder() { return use_block_based_builder_; }
private:
size_t bits_per_key_;
size_t num_probes_;
uint32_t (*hash_func_)(const Slice& key);
const bool use_block_based_builder_;
void initialize() {
// We intentionally round down to reduce probing cost a little bit
num_probes_ = static_cast<size_t>(bits_per_key_ * 0.69); // 0.69 =~ ln(2)
if (num_probes_ < 1) num_probes_ = 1;
if (num_probes_ > 30) num_probes_ = 30;
}
};
} // namespace
const FilterPolicy* NewBloomFilterPolicy(int bits_per_key,
bool use_block_based_builder) {
return new BloomFilterPolicy(bits_per_key, use_block_based_builder);
}
} // namespace rocksdb

147
util/bloom_test.cc
View File

@ -16,12 +16,13 @@ int main() {
#else
#include <gflags/gflags.h>
#include <vector>
#include "rocksdb/filter_policy.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "util/testutil.h"
#include "util/arena.h"
using GFLAGS::ParseCommandLineFlags;
@ -36,6 +37,19 @@ static Slice Key(int i, char* buffer) {
return Slice(buffer, sizeof(i));
}
static int NextLength(int length) {
if (length < 10) {
length += 1;
} else if (length < 100) {
length += 10;
} else if (length < 1000) {
length += 100;
} else {
length += 1000;
}
return length;
}
class BloomTest {
private:
const FilterPolicy* policy_;
@ -43,7 +57,8 @@ class BloomTest {
std::vector<std::string> keys_;
public:
BloomTest() : policy_(NewBloomFilterPolicy(FLAGS_bits_per_key)) { }
BloomTest() : policy_(
NewBloomFilterPolicy(FLAGS_bits_per_key)) {}
~BloomTest() {
delete policy_;
@ -117,19 +132,6 @@ TEST(BloomTest, Small) {
ASSERT_TRUE(! Matches("foo"));
}
static int NextLength(int length) {
if (length < 10) {
length += 1;
} else if (length < 100) {
length += 10;
} else if (length < 1000) {
length += 100;
} else {
length += 1000;
}
return length;
}
TEST(BloomTest, VaryingLengths) {
char buffer[sizeof(int)];
@ -171,6 +173,121 @@ TEST(BloomTest, VaryingLengths) {
// Different bits-per-byte
class FullBloomTest {
private:
const FilterPolicy* policy_;
std::unique_ptr<FilterBitsBuilder> bits_builder_;
std::unique_ptr<FilterBitsReader> bits_reader_;
std::unique_ptr<const char[]> buf_;
size_t filter_size_;
public:
FullBloomTest() :
policy_(NewBloomFilterPolicy(FLAGS_bits_per_key, false)),
filter_size_(0) {
Reset();
}
~FullBloomTest() {
delete policy_;
}
void Reset() {
bits_builder_.reset(policy_->GetFilterBitsBuilder());
bits_reader_.reset(nullptr);
buf_.reset(nullptr);
filter_size_ = 0;
}
void Add(const Slice& s) {
bits_builder_->AddKey(s);
}
void Build() {
Slice filter = bits_builder_->Finish(&buf_);
bits_reader_.reset(policy_->GetFilterBitsReader(filter));
filter_size_ = filter.size();
}
size_t FilterSize() const {
return filter_size_;
}
bool Matches(const Slice& s) {
if (bits_reader_ == nullptr) {
Build();
}
return bits_reader_->MayMatch(s);
}
double FalsePositiveRate() {
char buffer[sizeof(int)];
int result = 0;
for (int i = 0; i < 10000; i++) {
if (Matches(Key(i + 1000000000, buffer))) {
result++;
}
}
return result / 10000.0;
}
};
TEST(FullBloomTest, FullEmptyFilter) {
// Empty filter is not match, at this level
ASSERT_TRUE(!Matches("hello"));
ASSERT_TRUE(!Matches("world"));
}
TEST(FullBloomTest, FullSmall) {
Add("hello");
Add("world");
ASSERT_TRUE(Matches("hello"));
ASSERT_TRUE(Matches("world"));
ASSERT_TRUE(!Matches("x"));
ASSERT_TRUE(!Matches("foo"));
}
TEST(FullBloomTest, FullVaryingLengths) {
char buffer[sizeof(int)];
// Count number of filters that significantly exceed the false positive rate
int mediocre_filters = 0;
int good_filters = 0;
for (int length = 1; length <= 10000; length = NextLength(length)) {
Reset();
for (int i = 0; i < length; i++) {
Add(Key(i, buffer));
}
Build();
ASSERT_LE(FilterSize(), (size_t)((length * 10 / 8) + 128 + 5)) << length;
// All added keys must match
for (int i = 0; i < length; i++) {
ASSERT_TRUE(Matches(Key(i, buffer)))
<< "Length " << length << "; key " << i;
}
// Check false positive rate
double rate = FalsePositiveRate();
if (kVerbose >= 1) {
fprintf(stderr, "False positives: %5.2f%% @ length = %6d ; bytes = %6d\n",
rate*100.0, length, static_cast<int>(FilterSize()));
}
ASSERT_LE(rate, 0.02); // Must not be over 2%
if (rate > 0.0125)
mediocre_filters++; // Allowed, but not too often
else
good_filters++;
}
if (kVerbose >= 1) {
fprintf(stderr, "Filters: %d good, %d mediocre\n",
good_filters, mediocre_filters);
}
ASSERT_LE(mediocre_filters, good_filters/5);
}
} // namespace rocksdb
int main(int argc, char** argv) {