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4fc442029a
rocksdb/table/block_based_table_builder.cc
Andrew Kryczka 62f70f6d14 Reduce scope of compression dictionary to single SST (#4952) 
Summary:
Our previous approach was to train one compression dictionary per compaction, using the first output SST to train a dictionary, and then applying it on subsequent SSTs in the same compaction. While this was great for minimizing CPU/memory/I/O overhead, it did not achieve good compression ratios in practice. In our most promising potential use case, moderate reductions in a dictionary's scope make a major difference on compression ratio.

So, this PR changes compression dictionary to be scoped per-SST. It accepts the tradeoff during table building to use more memory and CPU. Important changes include:

- The `BlockBasedTableBuilder` has a new state when dictionary compression is in-use: `kBuffered`. In that state it accumulates uncompressed data in-memory whenever `Add` is called.
- After accumulating target file size bytes or calling `BlockBasedTableBuilder::Finish`, a `BlockBasedTableBuilder` moves to the `kUnbuffered` state. The transition (`EnterUnbuffered()`) involves sampling the buffered data, training a dictionary, and compressing/writing out all buffered data. In the `kUnbuffered` state, a `BlockBasedTableBuilder` behaves the same as before -- blocks are compressed/written out as soon as they fill up.
- Samples are now whole uncompressed data blocks, except the final sample may be a partial data block so we don't breach the user's configured `max_dict_bytes` or `zstd_max_train_bytes`. The dictionary trainer is supposed to work better when we pass it real units of compression. Previously we were passing 64-byte KV samples which was not realistic.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4952

Differential Revision: D13967980

Pulled By: ajkr

fbshipit-source-id: 82bea6f7537e1529c7a1a4cdee84585f5949300f
2019-02-11 19:47:32 -08:00

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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).
//
// Copyright (c) 2011 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_table_builder.h"
#include <assert.h>
#include <stdio.h>
#include <list>
#include <map>
#include <memory>
#include <string>
#include <unordered_map>
#include <utility>
#include "db/dbformat.h"
#include "rocksdb/cache.h"
#include "rocksdb/comparator.h"
#include "rocksdb/env.h"
#include "rocksdb/filter_policy.h"
#include "rocksdb/flush_block_policy.h"
#include "rocksdb/merge_operator.h"
#include "rocksdb/table.h"
#include "table/block.h"
#include "table/block_based_filter_block.h"
#include "table/block_based_table_factory.h"
#include "table/block_based_table_reader.h"
#include "table/block_builder.h"
#include "table/filter_block.h"
#include "table/format.h"
#include "table/full_filter_block.h"
#include "table/table_builder.h"
#include "util/coding.h"
#include "util/compression.h"
#include "util/crc32c.h"
#include "util/memory_allocator.h"
#include "util/stop_watch.h"
#include "util/string_util.h"
#include "util/xxhash.h"
#include "table/index_builder.h"
#include "table/partitioned_filter_block.h"
namespace rocksdb {
extern const std::string kHashIndexPrefixesBlock;
extern const std::string kHashIndexPrefixesMetadataBlock;
typedef BlockBasedTableOptions::IndexType IndexType;
// Without anonymous namespace here, we fail the warning -Wmissing-prototypes
namespace {
// Create a filter block builder based on its type.
FilterBlockBuilder* CreateFilterBlockBuilder(
const ImmutableCFOptions& /*opt*/, const MutableCFOptions& mopt,
const BlockBasedTableOptions& table_opt,
const bool use_delta_encoding_for_index_values,
PartitionedIndexBuilder* const p_index_builder) {
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(mopt.prefix_extractor.get(),
table_opt);
} else {
if (table_opt.partition_filters) {
assert(p_index_builder != nullptr);
// Since after partition cut request from filter builder it takes time
// until index builder actully cuts the partition, we take the lower bound
// as partition size.
assert(table_opt.block_size_deviation <= 100);
auto partition_size = static_cast<uint32_t>(
((table_opt.metadata_block_size *
(100 - table_opt.block_size_deviation)) + 99) / 100);
partition_size = std::max(partition_size, static_cast<uint32_t>(1));
return new PartitionedFilterBlockBuilder(
mopt.prefix_extractor.get(), table_opt.whole_key_filtering,
filter_bits_builder, table_opt.index_block_restart_interval,
use_delta_encoding_for_index_values, p_index_builder, partition_size);
} else {
return new FullFilterBlockBuilder(mopt.prefix_extractor.get(),
table_opt.whole_key_filtering,
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);
}
} // namespace
// format_version is the block format as defined in include/rocksdb/table.h
Slice CompressBlock(const Slice& raw, const CompressionInfo& compression_info,
CompressionType* type, uint32_t format_version,
std::string* compressed_output) {
*type = compression_info.type();
if (compression_info.type() == kNoCompression) {
return raw;
}
// Will return compressed block contents if (1) the compression method is
// supported in this platform and (2) the compression rate is "good enough".
switch (compression_info.type()) {
case kSnappyCompression:
if (Snappy_Compress(compression_info, raw.data(), raw.size(),
compressed_output) &&
GoodCompressionRatio(compressed_output->size(), raw.size())) {
return *compressed_output;
}
break; // fall back to no compression.
case kZlibCompression:
if (Zlib_Compress(
compression_info,
GetCompressFormatForVersion(kZlibCompression, format_version),
raw.data(), raw.size(), compressed_output) &&
GoodCompressionRatio(compressed_output->size(), raw.size())) {
return *compressed_output;
}
break; // fall back to no compression.
case kBZip2Compression:
if (BZip2_Compress(
compression_info,
GetCompressFormatForVersion(kBZip2Compression, format_version),
raw.data(), raw.size(), compressed_output) &&
GoodCompressionRatio(compressed_output->size(), raw.size())) {
return *compressed_output;
}
break; // fall back to no compression.
case kLZ4Compression:
if (LZ4_Compress(
compression_info,
GetCompressFormatForVersion(kLZ4Compression, format_version),
raw.data(), raw.size(), compressed_output) &&
GoodCompressionRatio(compressed_output->size(), raw.size())) {
return *compressed_output;
}
break; // fall back to no compression.
case kLZ4HCCompression:
if (LZ4HC_Compress(
compression_info,
GetCompressFormatForVersion(kLZ4HCCompression, format_version),
raw.data(), raw.size(), compressed_output) &&
GoodCompressionRatio(compressed_output->size(), raw.size())) {
return *compressed_output;
}
break; // fall back to no compression.
case kXpressCompression:
if (XPRESS_Compress(raw.data(), raw.size(),
compressed_output) &&
GoodCompressionRatio(compressed_output->size(), raw.size())) {
return *compressed_output;
}
break;
case kZSTD:
case kZSTDNotFinalCompression:
if (ZSTD_Compress(compression_info, raw.data(), raw.size(),
compressed_output) &&
GoodCompressionRatio(compressed_output->size(), raw.size())) {
return *compressed_output;
}
break; // fall back to no compression.
default: {} // Do not recognize this compression type
}
// Compression method is not supported, or not good compression ratio, so just
// fall back to uncompressed form.
*type = kNoCompression;
return raw;
}
// kBlockBasedTableMagicNumber was picked by running
// echo rocksdb.table.block_based | sha1sum
// and taking the leading 64 bits.
// Please note that kBlockBasedTableMagicNumber may also be accessed by other
// .cc files
// for that reason we declare it extern in the header but to get the space
// allocated
// it must be not extern in one place.
const uint64_t kBlockBasedTableMagicNumber = 0x88e241b785f4cff7ull;
// We also support reading and writing legacy block based table format (for
// backwards compatibility)
const uint64_t kLegacyBlockBasedTableMagicNumber = 0xdb4775248b80fb57ull;
// A collector that collects properties of interest to block-based table.
// For now this class looks heavy-weight since we only write one additional
// property.
// But in the foreseeable future, we will add more and more properties that are
// specific to block-based table.
class BlockBasedTableBuilder::BlockBasedTablePropertiesCollector
: public IntTblPropCollector {
public:
explicit BlockBasedTablePropertiesCollector(
BlockBasedTableOptions::IndexType index_type, bool whole_key_filtering,
bool prefix_filtering)
: index_type_(index_type),
whole_key_filtering_(whole_key_filtering),
prefix_filtering_(prefix_filtering) {}
virtual Status InternalAdd(const Slice& /*key*/, const Slice& /*value*/,
uint64_t /*file_size*/) override {
// Intentionally left blank. Have no interest in collecting stats for
// individual key/value pairs.
return Status::OK();
}
virtual Status Finish(UserCollectedProperties* properties) override {
std::string val;
PutFixed32(&val, static_cast<uint32_t>(index_type_));
properties->insert({BlockBasedTablePropertyNames::kIndexType, val});
properties->insert({BlockBasedTablePropertyNames::kWholeKeyFiltering,
whole_key_filtering_ ? kPropTrue : kPropFalse});
properties->insert({BlockBasedTablePropertyNames::kPrefixFiltering,
prefix_filtering_ ? kPropTrue : kPropFalse});
return Status::OK();
}
// The name of the properties collector can be used for debugging purpose.
virtual const char* Name() const override {
return "BlockBasedTablePropertiesCollector";
}
virtual UserCollectedProperties GetReadableProperties() const override {
// Intentionally left blank.
return UserCollectedProperties();
}
private:
BlockBasedTableOptions::IndexType index_type_;
bool whole_key_filtering_;
bool prefix_filtering_;
};
struct BlockBasedTableBuilder::Rep {
const ImmutableCFOptions ioptions;
const MutableCFOptions moptions;
const BlockBasedTableOptions table_options;
const InternalKeyComparator& internal_comparator;
WritableFileWriter* file;
uint64_t offset = 0;
Status status;
size_t alignment;
BlockBuilder data_block;
// Buffers uncompressed data blocks and keys to replay later. Needed when
// compression dictionary is enabled so we can finalize the dictionary before
// compressing any data blocks.
// TODO(ajkr): ideally we don't buffer all keys and all uncompressed data
// blocks as it's redundant, but it's easier to implement for now.
std::vector<std::pair<std::string, std::vector<std::string>>>
data_block_and_keys_buffers;
BlockBuilder range_del_block;
InternalKeySliceTransform internal_prefix_transform;
std::unique_ptr<IndexBuilder> index_builder;
PartitionedIndexBuilder* p_index_builder_ = nullptr;
std::string last_key;
CompressionType compression_type;
CompressionOptions compression_opts;
std::unique_ptr<CompressionDict> compression_dict;
CompressionContext compression_ctx;
std::unique_ptr<UncompressionContext> verify_ctx;
std::unique_ptr<UncompressionDict> verify_dict;
size_t data_begin_offset = 0;
TableProperties props;
// States of the builder.
//
// - `kBuffered`: This is the initial state where zero or more data blocks are
// accumulated uncompressed in-memory. From this state, call
// `EnterUnbuffered()` to finalize the compression dictionary if enabled,
// compress/write out any buffered blocks, and proceed to the `kUnbuffered`
// state.
//
// - `kUnbuffered`: This is the state when compression dictionary is finalized
// either because it wasn't enabled in the first place or it's been created
// from sampling previously buffered data. In this state, blocks are simply
// compressed/written out as they fill up. From this state, call `Finish()`
// to complete the file (write meta-blocks, etc.), or `Abandon()` to delete
// the partially created file.
//
// - `kClosed`: This indicates either `Finish()` or `Abandon()` has been
// called, so the table builder is no longer usable. We must be in this
// state by the time the destructor runs.
enum class State {
kBuffered,
kUnbuffered,
kClosed,
};
State state;
const bool use_delta_encoding_for_index_values;
std::unique_ptr<FilterBlockBuilder> filter_builder;
char compressed_cache_key_prefix[BlockBasedTable::kMaxCacheKeyPrefixSize];
size_t compressed_cache_key_prefix_size;
BlockHandle pending_handle; // Handle to add to index block
std::string compressed_output;
std::unique_ptr<FlushBlockPolicy> flush_block_policy;
uint32_t column_family_id;
const std::string& column_family_name;
uint64_t creation_time = 0;
uint64_t oldest_key_time = 0;
const bool is_bottommost_level;
const uint64_t target_file_size;
std::vector<std::unique_ptr<IntTblPropCollector>> table_properties_collectors;
Rep(const ImmutableCFOptions& _ioptions, const MutableCFOptions& _moptions,
const BlockBasedTableOptions& table_opt,
const InternalKeyComparator& icomparator,
const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
int_tbl_prop_collector_factories,
uint32_t _column_family_id, WritableFileWriter* f,
const CompressionType _compression_type,
const CompressionOptions& _compression_opts, const bool skip_filters,
const std::string& _column_family_name, const uint64_t _creation_time,
const uint64_t _oldest_key_time, const bool _is_bottommost_level,
const uint64_t _target_file_size)
: ioptions(_ioptions),
moptions(_moptions),
table_options(table_opt),
internal_comparator(icomparator),
file(f),
alignment(table_options.block_align
? std::min(table_options.block_size, kDefaultPageSize)
: 0),
data_block(table_options.block_restart_interval,
table_options.use_delta_encoding,
false /* use_value_delta_encoding */,
icomparator.user_comparator()
->CanKeysWithDifferentByteContentsBeEqual()
? BlockBasedTableOptions::kDataBlockBinarySearch
: table_options.data_block_index_type,
table_options.data_block_hash_table_util_ratio),
range_del_block(1 /* block_restart_interval */),
internal_prefix_transform(_moptions.prefix_extractor.get()),
compression_type(_compression_type),
compression_opts(_compression_opts),
compression_dict(),
compression_ctx(_compression_type),
verify_dict(),
state((_is_bottommost_level && _compression_opts.max_dict_bytes > 0)
? State::kBuffered
: State::kUnbuffered),
use_delta_encoding_for_index_values(table_opt.format_version >= 4 &&
!table_opt.block_align),
compressed_cache_key_prefix_size(0),
flush_block_policy(
table_options.flush_block_policy_factory->NewFlushBlockPolicy(
table_options, data_block)),
column_family_id(_column_family_id),
column_family_name(_column_family_name),
creation_time(_creation_time),
oldest_key_time(_oldest_key_time),
is_bottommost_level(_is_bottommost_level),
target_file_size(_target_file_size) {
if (table_options.index_type ==
BlockBasedTableOptions::kTwoLevelIndexSearch) {
p_index_builder_ = PartitionedIndexBuilder::CreateIndexBuilder(
&internal_comparator, use_delta_encoding_for_index_values,
table_options);
index_builder.reset(p_index_builder_);
} else {
index_builder.reset(IndexBuilder::CreateIndexBuilder(
table_options.index_type, &internal_comparator,
&this->internal_prefix_transform, use_delta_encoding_for_index_values,
table_options));
}
if (skip_filters) {
filter_builder = nullptr;
} else {
filter_builder.reset(CreateFilterBlockBuilder(
_ioptions, _moptions, table_options,
use_delta_encoding_for_index_values, p_index_builder_));
}
for (auto& collector_factories : *int_tbl_prop_collector_factories) {
table_properties_collectors.emplace_back(
collector_factories->CreateIntTblPropCollector(column_family_id));
}
table_properties_collectors.emplace_back(
new BlockBasedTablePropertiesCollector(
table_options.index_type, table_options.whole_key_filtering,
_moptions.prefix_extractor != nullptr));
if (table_options.verify_compression) {
verify_ctx.reset(new UncompressionContext(UncompressionContext::NoCache(),
compression_type));
}
}
Rep(const Rep&) = delete;
Rep& operator=(const Rep&) = delete;
~Rep() {}
};
BlockBasedTableBuilder::BlockBasedTableBuilder(
const ImmutableCFOptions& ioptions, const MutableCFOptions& moptions,
const BlockBasedTableOptions& table_options,
const InternalKeyComparator& internal_comparator,
const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
int_tbl_prop_collector_factories,
uint32_t column_family_id, WritableFileWriter* file,
const CompressionType compression_type,
const CompressionOptions& compression_opts, const bool skip_filters,
const std::string& column_family_name, const uint64_t creation_time,
const uint64_t oldest_key_time, const bool is_bottommost_level,
const uint64_t target_file_size) {
BlockBasedTableOptions sanitized_table_options(table_options);
if (sanitized_table_options.format_version == 0 &&
sanitized_table_options.checksum != kCRC32c) {
ROCKS_LOG_WARN(
ioptions.info_log,
"Silently converting format_version to 1 because checksum is "
"non-default");
// silently convert format_version to 1 to keep consistent with current
// behavior
sanitized_table_options.format_version = 1;
}
rep_ = new Rep(ioptions, moptions, sanitized_table_options,
internal_comparator, int_tbl_prop_collector_factories,
column_family_id, file, compression_type, compression_opts,
skip_filters, column_family_name, creation_time,
oldest_key_time, is_bottommost_level, target_file_size);
if (rep_->filter_builder != nullptr) {
rep_->filter_builder->StartBlock(0);
}
if (table_options.block_cache_compressed.get() != nullptr) {
BlockBasedTable::GenerateCachePrefix(
table_options.block_cache_compressed.get(), file->writable_file(),
&rep_->compressed_cache_key_prefix[0],
&rep_->compressed_cache_key_prefix_size);
}
}
BlockBasedTableBuilder::~BlockBasedTableBuilder() {
// Catch errors where caller forgot to call Finish()
assert(rep_->state == Rep::State::kClosed);
delete rep_;
}
void BlockBasedTableBuilder::Add(const Slice& key, const Slice& value) {
Rep* r = rep_;
assert(rep_->state != Rep::State::kClosed);
if (!ok()) return;
ValueType value_type = ExtractValueType(key);
if (IsValueType(value_type)) {
#ifndef NDEBUG
if (r->props.num_entries > r->props.num_range_deletions) {
assert(r->internal_comparator.Compare(key, Slice(r->last_key)) > 0);
}
#endif // NDEBUG
auto should_flush = r->flush_block_policy->Update(key, value);
if (should_flush) {
assert(!r->data_block.empty());
Flush();
if (r->state == Rep::State::kBuffered &&
r->data_begin_offset > r->target_file_size) {
EnterUnbuffered();
}
// Add item to index block.
// We do not emit the index entry for a block until we have seen the
// first key for the next data block. This allows us to use shorter
// keys in the index block. For example, consider a block boundary
// between the keys "the quick brown fox" and "the who". We can use
// "the r" as the key for the index block entry since it is >= all
// entries in the first block and < all entries in subsequent
// blocks.
if (ok() && r->state == Rep::State::kUnbuffered) {
r->index_builder->AddIndexEntry(&r->last_key, &key, r->pending_handle);
}
}
// Note: PartitionedFilterBlockBuilder requires key being added to filter
// builder after being added to index builder.
if (r->state == Rep::State::kUnbuffered && r->filter_builder != nullptr) {
r->filter_builder->Add(ExtractUserKey(key));
}
r->last_key.assign(key.data(), key.size());
r->data_block.Add(key, value);
if (r->state == Rep::State::kBuffered) {
// Buffer keys to be replayed during `Finish()` once compression
// dictionary has been finalized.
if (r->data_block_and_keys_buffers.empty() || should_flush) {
r->data_block_and_keys_buffers.emplace_back();
}
r->data_block_and_keys_buffers.back().second.emplace_back(key.ToString());
} else {
r->index_builder->OnKeyAdded(key);
}
NotifyCollectTableCollectorsOnAdd(key, value, r->offset,
r->table_properties_collectors,
r->ioptions.info_log);
} else if (value_type == kTypeRangeDeletion) {
r->range_del_block.Add(key, value);
NotifyCollectTableCollectorsOnAdd(key, value, r->offset,
r->table_properties_collectors,
r->ioptions.info_log);
} else {
assert(false);
}
r->props.num_entries++;
r->props.raw_key_size += key.size();
r->props.raw_value_size += value.size();
if (value_type == kTypeDeletion || value_type == kTypeSingleDeletion) {
r->props.num_deletions++;
} else if (value_type == kTypeRangeDeletion) {
r->props.num_deletions++;
r->props.num_range_deletions++;
} else if (value_type == kTypeMerge) {
r->props.num_merge_operands++;
}
}
void BlockBasedTableBuilder::Flush() {
Rep* r = rep_;
assert(rep_->state != Rep::State::kClosed);
if (!ok()) return;
if (r->data_block.empty()) return;
WriteBlock(&r->data_block, &r->pending_handle, true /* is_data_block */);
}
void BlockBasedTableBuilder::WriteBlock(BlockBuilder* block,
BlockHandle* handle,
bool is_data_block) {
WriteBlock(block->Finish(), handle, is_data_block);
block->Reset();
}
void BlockBasedTableBuilder::WriteBlock(const Slice& raw_block_contents,
BlockHandle* handle,
bool is_data_block) {
// File format contains a sequence of blocks where each block has:
// block_data: uint8[n]
// type: uint8
// crc: uint32
assert(ok());
Rep* r = rep_;
auto type = r->compression_type;
Slice block_contents;
bool abort_compression = false;
StopWatchNano timer(r->ioptions.env,
ShouldReportDetailedTime(r->ioptions.env, r->ioptions.statistics));
if (r->state == Rep::State::kBuffered) {
assert(is_data_block);
assert(!r->data_block_and_keys_buffers.empty());
r->data_block_and_keys_buffers.back().first = raw_block_contents.ToString();
r->data_begin_offset += r->data_block_and_keys_buffers.back().first.size();
return;
}
if (raw_block_contents.size() < kCompressionSizeLimit) {
const CompressionDict* compression_dict;
if (!is_data_block || r->compression_dict == nullptr) {
compression_dict = &CompressionDict::GetEmptyDict();
} else {
compression_dict = r->compression_dict.get();
}
assert(compression_dict != nullptr);
CompressionInfo compression_info(r->compression_opts, r->compression_ctx,
*compression_dict, r->compression_type);
block_contents =
CompressBlock(raw_block_contents, compression_info, &type,
r->table_options.format_version, &r->compressed_output);
// Some of the compression algorithms are known to be unreliable. If
// the verify_compression flag is set then try to de-compress the
// compressed data and compare to the input.
if (type != kNoCompression && r->table_options.verify_compression) {
// Retrieve the uncompressed contents into a new buffer
const UncompressionDict* verify_dict;
if (!is_data_block || r->verify_dict == nullptr) {
verify_dict = &UncompressionDict::GetEmptyDict();
} else {
verify_dict = r->verify_dict.get();
}
assert(verify_dict != nullptr);
BlockContents contents;
UncompressionInfo uncompression_info(*r->verify_ctx, *verify_dict,
r->compression_type);
Status stat = UncompressBlockContentsForCompressionType(
uncompression_info, block_contents.data(), block_contents.size(),
&contents, r->table_options.format_version, r->ioptions);
if (stat.ok()) {
bool compressed_ok = contents.data.compare(raw_block_contents) == 0;
if (!compressed_ok) {
// The result of the compression was invalid. abort.
abort_compression = true;
ROCKS_LOG_ERROR(r->ioptions.info_log,
"Decompressed block did not match raw block");
r->status =
Status::Corruption("Decompressed block did not match raw block");
}
} else {
// Decompression reported an error. abort.
r->status = Status::Corruption("Could not decompress");
abort_compression = true;
}
}
} else {
// Block is too big to be compressed.
abort_compression = true;
}
// Abort compression if the block is too big, or did not pass
// verification.
if (abort_compression) {
RecordTick(r->ioptions.statistics, NUMBER_BLOCK_NOT_COMPRESSED);
type = kNoCompression;
block_contents = raw_block_contents;
} else if (type != kNoCompression) {
if (ShouldReportDetailedTime(r->ioptions.env, r->ioptions.statistics)) {
MeasureTime(r->ioptions.statistics, COMPRESSION_TIMES_NANOS,
timer.ElapsedNanos());
}
MeasureTime(r->ioptions.statistics, BYTES_COMPRESSED,
raw_block_contents.size());
RecordTick(r->ioptions.statistics, NUMBER_BLOCK_COMPRESSED);
} else if (type != r->compression_type) {
RecordTick(r->ioptions.statistics, NUMBER_BLOCK_NOT_COMPRESSED);
}
WriteRawBlock(block_contents, type, handle, is_data_block);
r->compressed_output.clear();
if (is_data_block) {
if (r->filter_builder != nullptr) {
r->filter_builder->StartBlock(r->offset);
}
r->props.data_size = r->offset;
++r->props.num_data_blocks;
}
}
void BlockBasedTableBuilder::WriteRawBlock(const Slice& block_contents,
CompressionType type,
BlockHandle* handle,
bool is_data_block) {
Rep* r = rep_;
StopWatch sw(r->ioptions.env, r->ioptions.statistics, WRITE_RAW_BLOCK_MICROS);
handle->set_offset(r->offset);
handle->set_size(block_contents.size());
assert(r->status.ok());
r->status = r->file->Append(block_contents);
if (r->status.ok()) {
char trailer[kBlockTrailerSize];
trailer[0] = type;
char* trailer_without_type = trailer + 1;
switch (r->table_options.checksum) {
case kNoChecksum:
EncodeFixed32(trailer_without_type, 0);
break;
case kCRC32c: {
auto crc = crc32c::Value(block_contents.data(), block_contents.size());
crc = crc32c::Extend(crc, trailer, 1); // Extend to cover block type
EncodeFixed32(trailer_without_type, crc32c::Mask(crc));
break;
}
case kxxHash: {
void* xxh = XXH32_init(0);
XXH32_update(xxh, block_contents.data(),
static_cast<uint32_t>(block_contents.size()));
XXH32_update(xxh, trailer, 1); // Extend to cover block type
EncodeFixed32(trailer_without_type, XXH32_digest(xxh));
break;
}
case kxxHash64: {
XXH64_state_t* const state = XXH64_createState();
XXH64_reset(state, 0);
XXH64_update(state, block_contents.data(),
static_cast<uint32_t>(block_contents.size()));
XXH64_update(state, trailer, 1); // Extend to cover block type
EncodeFixed32(trailer_without_type,
static_cast<uint32_t>(XXH64_digest(state) & // lower 32 bits
uint64_t{0xffffffff}));
XXH64_freeState(state);
break;
}
}
assert(r->status.ok());
TEST_SYNC_POINT_CALLBACK(
"BlockBasedTableBuilder::WriteRawBlock:TamperWithChecksum",
static_cast<char*>(trailer));
r->status = r->file->Append(Slice(trailer, kBlockTrailerSize));
if (r->status.ok()) {
r->status = InsertBlockInCache(block_contents, type, handle);
}
if (r->status.ok()) {
r->offset += block_contents.size() + kBlockTrailerSize;
if (r->table_options.block_align && is_data_block) {
size_t pad_bytes =
(r->alignment - ((block_contents.size() + kBlockTrailerSize) &
(r->alignment - 1))) &
(r->alignment - 1);
r->status = r->file->Pad(pad_bytes);
if (r->status.ok()) {
r->offset += pad_bytes;
}
}
}
}
}
Status BlockBasedTableBuilder::status() const {
return rep_->status;
}
static void DeleteCachedBlockContents(const Slice& /*key*/, void* value) {
BlockContents* bc = reinterpret_cast<BlockContents*>(value);
delete bc;
}
//
// Make a copy of the block contents and insert into compressed block cache
//
Status BlockBasedTableBuilder::InsertBlockInCache(const Slice& block_contents,
const CompressionType type,
const BlockHandle* handle) {
Rep* r = rep_;
Cache* block_cache_compressed = r->table_options.block_cache_compressed.get();
if (type != kNoCompression && block_cache_compressed != nullptr) {
size_t size = block_contents.size();
auto ubuf =
AllocateBlock(size + 1, block_cache_compressed->memory_allocator());
memcpy(ubuf.get(), block_contents.data(), size);
ubuf[size] = type;
BlockContents* block_contents_to_cache =
new BlockContents(std::move(ubuf), size);
#ifndef NDEBUG
block_contents_to_cache->is_raw_block = true;
#endif // NDEBUG
// make cache key by appending the file offset to the cache prefix id
char* end = EncodeVarint64(
r->compressed_cache_key_prefix +
r->compressed_cache_key_prefix_size,
handle->offset());
Slice key(r->compressed_cache_key_prefix, static_cast<size_t>
(end - r->compressed_cache_key_prefix));
// Insert into compressed block cache.
block_cache_compressed->Insert(
key, block_contents_to_cache,
block_contents_to_cache->ApproximateMemoryUsage(),
&DeleteCachedBlockContents);
// Invalidate OS cache.
r->file->InvalidateCache(static_cast<size_t>(r->offset), size);
}
return Status::OK();
}
void BlockBasedTableBuilder::WriteFilterBlock(
MetaIndexBuilder* meta_index_builder) {
BlockHandle filter_block_handle;
bool empty_filter_block = (rep_->filter_builder == nullptr ||
rep_->filter_builder->NumAdded() == 0);
if (ok() && !empty_filter_block) {
Status s = Status::Incomplete();
while (ok() && s.IsIncomplete()) {
Slice filter_content =
rep_->filter_builder->Finish(filter_block_handle, &s);
assert(s.ok() || s.IsIncomplete());
rep_->props.filter_size += filter_content.size();
WriteRawBlock(filter_content, kNoCompression, &filter_block_handle);
}
}
if (ok() && !empty_filter_block) {
// Add mapping from "<filter_block_prefix>.Name" to location
// of filter data.
std::string key;
if (rep_->filter_builder->IsBlockBased()) {
key = BlockBasedTable::kFilterBlockPrefix;
} else {
key = rep_->table_options.partition_filters
? BlockBasedTable::kPartitionedFilterBlockPrefix
: BlockBasedTable::kFullFilterBlockPrefix;
}
key.append(rep_->table_options.filter_policy->Name());
meta_index_builder->Add(key, filter_block_handle);
}
}
void BlockBasedTableBuilder::WriteIndexBlock(
MetaIndexBuilder* meta_index_builder, BlockHandle* index_block_handle) {
IndexBuilder::IndexBlocks index_blocks;
auto index_builder_status = rep_->index_builder->Finish(&index_blocks);
if (index_builder_status.IsIncomplete()) {
// We we have more than one index partition then meta_blocks are not
// supported for the index. Currently meta_blocks are used only by
// HashIndexBuilder which is not multi-partition.
assert(index_blocks.meta_blocks.empty());
} else if (ok() && !index_builder_status.ok()) {
rep_->status = index_builder_status;
}
if (ok()) {
for (const auto& item : index_blocks.meta_blocks) {
BlockHandle block_handle;
WriteBlock(item.second, &block_handle, false /* is_data_block */);
if (!ok()) {
break;
}
meta_index_builder->Add(item.first, block_handle);
}
}
if (ok()) {
if (rep_->table_options.enable_index_compression) {
WriteBlock(index_blocks.index_block_contents, index_block_handle, false);
} else {
WriteRawBlock(index_blocks.index_block_contents, kNoCompression,
index_block_handle);
}
}
// If there are more index partitions, finish them and write them out
Status s = index_builder_status;
while (ok() && s.IsIncomplete()) {
s = rep_->index_builder->Finish(&index_blocks, *index_block_handle);
if (!s.ok() && !s.IsIncomplete()) {
rep_->status = s;
return;
}
if (rep_->table_options.enable_index_compression) {
WriteBlock(index_blocks.index_block_contents, index_block_handle, false);
} else {
WriteRawBlock(index_blocks.index_block_contents, kNoCompression,
index_block_handle);
}
// The last index_block_handle will be for the partition index block
}
}
void BlockBasedTableBuilder::WritePropertiesBlock(
MetaIndexBuilder* meta_index_builder) {
BlockHandle properties_block_handle;
if (ok()) {
PropertyBlockBuilder property_block_builder;
rep_->props.column_family_id = rep_->column_family_id;
rep_->props.column_family_name = rep_->column_family_name;
rep_->props.filter_policy_name =
rep_->table_options.filter_policy != nullptr
? rep_->table_options.filter_policy->Name()
: "";
rep_->props.index_size =
rep_->index_builder->IndexSize() + kBlockTrailerSize;
rep_->props.comparator_name = rep_->ioptions.user_comparator != nullptr
? rep_->ioptions.user_comparator->Name()
: "nullptr";
rep_->props.merge_operator_name =
rep_->ioptions.merge_operator != nullptr
? rep_->ioptions.merge_operator->Name()
: "nullptr";
rep_->props.compression_name =
CompressionTypeToString(rep_->compression_type);
rep_->props.prefix_extractor_name =
rep_->moptions.prefix_extractor != nullptr
? rep_->moptions.prefix_extractor->Name()
: "nullptr";
std::string property_collectors_names = "[";
for (size_t i = 0;
i < rep_->ioptions.table_properties_collector_factories.size(); ++i) {
if (i != 0) {
property_collectors_names += ",";
}
property_collectors_names +=
rep_->ioptions.table_properties_collector_factories[i]->Name();
}
property_collectors_names += "]";
rep_->props.property_collectors_names = property_collectors_names;
if (rep_->table_options.index_type ==
BlockBasedTableOptions::kTwoLevelIndexSearch) {
assert(rep_->p_index_builder_ != nullptr);
rep_->props.index_partitions = rep_->p_index_builder_->NumPartitions();
rep_->props.top_level_index_size =
rep_->p_index_builder_->TopLevelIndexSize(rep_->offset);
}
rep_->props.index_key_is_user_key =
!rep_->index_builder->seperator_is_key_plus_seq();
rep_->props.index_value_is_delta_encoded =
rep_->use_delta_encoding_for_index_values;
rep_->props.creation_time = rep_->creation_time;
rep_->props.oldest_key_time = rep_->oldest_key_time;
// Add basic properties
property_block_builder.AddTableProperty(rep_->props);
// Add use collected properties
NotifyCollectTableCollectorsOnFinish(rep_->table_properties_collectors,
rep_->ioptions.info_log,
&property_block_builder);
WriteRawBlock(property_block_builder.Finish(), kNoCompression,
&properties_block_handle);
}
if (ok()) {
#ifndef NDEBUG
{
uint64_t props_block_offset = properties_block_handle.offset();
uint64_t props_block_size = properties_block_handle.size();
TEST_SYNC_POINT_CALLBACK(
"BlockBasedTableBuilder::WritePropertiesBlock:GetPropsBlockOffset",
&props_block_offset);
TEST_SYNC_POINT_CALLBACK(
"BlockBasedTableBuilder::WritePropertiesBlock:GetPropsBlockSize",
&props_block_size);
}
#endif // !NDEBUG
meta_index_builder->Add(kPropertiesBlock, properties_block_handle);
}
}
void BlockBasedTableBuilder::WriteCompressionDictBlock(
MetaIndexBuilder* meta_index_builder) {
if (rep_->compression_dict != nullptr &&
rep_->compression_dict->GetRawDict().size()) {
BlockHandle compression_dict_block_handle;
if (ok()) {
WriteRawBlock(rep_->compression_dict->GetRawDict(), kNoCompression,
&compression_dict_block_handle);
#ifndef NDEBUG
Slice compression_dict = rep_->compression_dict->GetRawDict();
TEST_SYNC_POINT_CALLBACK(
"BlockBasedTableBuilder::WriteCompressionDictBlock:RawDict",
&compression_dict);
#endif // NDEBUG
}
if (ok()) {
meta_index_builder->Add(kCompressionDictBlock,
compression_dict_block_handle);
}
}
}
void BlockBasedTableBuilder::WriteRangeDelBlock(
MetaIndexBuilder* meta_index_builder) {
if (ok() && !rep_->range_del_block.empty()) {
BlockHandle range_del_block_handle;
WriteRawBlock(rep_->range_del_block.Finish(), kNoCompression,
&range_del_block_handle);
meta_index_builder->Add(kRangeDelBlock, range_del_block_handle);
}
}
void BlockBasedTableBuilder::WriteFooter(BlockHandle& metaindex_block_handle,
BlockHandle& index_block_handle) {
Rep* r = rep_;
// No need to write out new footer if we're using default checksum.
// We're writing legacy magic number because we want old versions of RocksDB
// be able to read files generated with new release (just in case if
// somebody wants to roll back after an upgrade)
// TODO(icanadi) at some point in the future, when we're absolutely sure
// nobody will roll back to RocksDB 2.x versions, retire the legacy magic
// number and always write new table files with new magic number
bool legacy = (r->table_options.format_version == 0);
// this is guaranteed by BlockBasedTableBuilder's constructor
assert(r->table_options.checksum == kCRC32c ||
r->table_options.format_version != 0);
Footer footer(
legacy ? kLegacyBlockBasedTableMagicNumber : kBlockBasedTableMagicNumber,
r->table_options.format_version);
footer.set_metaindex_handle(metaindex_block_handle);
footer.set_index_handle(index_block_handle);
footer.set_checksum(r->table_options.checksum);
std::string footer_encoding;
footer.EncodeTo(&footer_encoding);
assert(r->status.ok());
r->status = r->file->Append(footer_encoding);
if (r->status.ok()) {
r->offset += footer_encoding.size();
}
}
void BlockBasedTableBuilder::EnterUnbuffered() {
Rep* r = rep_;
assert(r->state == Rep::State::kBuffered);
r->state = Rep::State::kUnbuffered;
const size_t kSampleBytes = r->compression_opts.zstd_max_train_bytes > 0
? r->compression_opts.zstd_max_train_bytes
: r->compression_opts.max_dict_bytes;
Random64 generator{r->creation_time};
std::string compression_dict_samples;
std::vector<size_t> compression_dict_sample_lens;
if (!r->data_block_and_keys_buffers.empty()) {
while (compression_dict_samples.size() < kSampleBytes) {
size_t rand_idx =
generator.Uniform(r->data_block_and_keys_buffers.size());
size_t copy_len =
std::min(kSampleBytes - compression_dict_samples.size(),
r->data_block_and_keys_buffers[rand_idx].first.size());
compression_dict_samples.append(
r->data_block_and_keys_buffers[rand_idx].first, 0, copy_len);
compression_dict_sample_lens.emplace_back(copy_len);
}
}
// final data block flushed, now we can generate dictionary from the samples.
// OK if compression_dict_samples is empty, we'll just get empty dictionary.
std::string dict;
if (r->compression_opts.zstd_max_train_bytes > 0) {
dict = ZSTD_TrainDictionary(compression_dict_samples,
compression_dict_sample_lens,
r->compression_opts.max_dict_bytes);
} else {
dict = std::move(compression_dict_samples);
}
r->compression_dict.reset(new CompressionDict(dict, r->compression_type,
r->compression_opts.level));
r->verify_dict.reset(new UncompressionDict(
dict, r->compression_type == kZSTD ||
r->compression_type == kZSTDNotFinalCompression));
for (size_t i = 0; ok() && i < r->data_block_and_keys_buffers.size(); ++i) {
const auto& data_block = r->data_block_and_keys_buffers[i].first;
auto& keys = r->data_block_and_keys_buffers[i].second;
assert(!data_block.empty());
assert(!keys.empty());
for (const auto& key : keys) {
if (r->filter_builder != nullptr) {
r->filter_builder->Add(ExtractUserKey(key));
}
r->index_builder->OnKeyAdded(key);
}
WriteBlock(Slice(data_block), &r->pending_handle, true /* is_data_block */);
if (ok() && i + 1 < r->data_block_and_keys_buffers.size()) {
Slice first_key_in_next_block =
r->data_block_and_keys_buffers[i + 1].second.front();
Slice* first_key_in_next_block_ptr = &first_key_in_next_block;
r->index_builder->AddIndexEntry(&keys.back(), first_key_in_next_block_ptr,
r->pending_handle);
}
}
r->data_block_and_keys_buffers.clear();
}
Status BlockBasedTableBuilder::Finish() {
Rep* r = rep_;
assert(r->state != Rep::State::kClosed);
bool empty_data_block = r->data_block.empty();
Flush();
if (r->state == Rep::State::kBuffered) {
EnterUnbuffered();
}
// To make sure properties block is able to keep the accurate size of index
// block, we will finish writing all index entries first.
if (ok() && !empty_data_block) {
r->index_builder->AddIndexEntry(
&r->last_key, nullptr /* no next data block */, r->pending_handle);
}
// Write meta blocks, metaindex block and footer in the following order.
// 1. [meta block: filter]
// 2. [meta block: index]
// 3. [meta block: compression dictionary]
// 4. [meta block: range deletion tombstone]
// 5. [meta block: properties]
// 6. [metaindex block]
// 7. Footer
BlockHandle metaindex_block_handle, index_block_handle;
MetaIndexBuilder meta_index_builder;
WriteFilterBlock(&meta_index_builder);
WriteIndexBlock(&meta_index_builder, &index_block_handle);
WriteCompressionDictBlock(&meta_index_builder);
WriteRangeDelBlock(&meta_index_builder);
WritePropertiesBlock(&meta_index_builder);
if (ok()) {
// flush the meta index block
WriteRawBlock(meta_index_builder.Finish(), kNoCompression,
&metaindex_block_handle);
}
if (ok()) {
WriteFooter(metaindex_block_handle, index_block_handle);
}
r->state = Rep::State::kClosed;
return r->status;
}
void BlockBasedTableBuilder::Abandon() {
assert(rep_->state != Rep::State::kClosed);
rep_->state = Rep::State::kClosed;
}
uint64_t BlockBasedTableBuilder::NumEntries() const {
return rep_->props.num_entries;
}
uint64_t BlockBasedTableBuilder::FileSize() const { return rep_->offset; }
bool BlockBasedTableBuilder::NeedCompact() const {
for (const auto& collector : rep_->table_properties_collectors) {
if (collector->NeedCompact()) {
return true;
}
}
return false;
}
TableProperties BlockBasedTableBuilder::GetTableProperties() const {
TableProperties ret = rep_->props;
for (const auto& collector : rep_->table_properties_collectors) {
for (const auto& prop : collector->GetReadableProperties()) {
ret.readable_properties.insert(prop);
}
collector->Finish(&ret.user_collected_properties);
}
return ret;
}
const std::string BlockBasedTable::kFilterBlockPrefix = "filter.";
const std::string BlockBasedTable::kFullFilterBlockPrefix = "fullfilter.";
const std::string BlockBasedTable::kPartitionedFilterBlockPrefix =
"partitionedfilter.";
} // namespace rocksdb
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