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rocksdb/table/block_based_table_builder.cc

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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// 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 <inttypes.h>
#include <stdio.h>
#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/table.h"
#include "table/block.h"
#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/block_based_table_factory.h"
#include "table/full_filter_block.h"
#include "table/format.h"
#include "table/meta_blocks.h"
#include "table/table_builder.h"
#include "util/string_util.h"
#include "util/coding.h"
#include "util/compression.h"
#include "util/crc32c.h"
#include "util/stop_watch.h"
#include "util/xxhash.h"
namespace rocksdb {
extern const std::string kHashIndexPrefixesBlock;
extern const std::string kHashIndexPrefixesMetadataBlock;
typedef BlockBasedTableOptions::IndexType IndexType;
// The interface for building index.
// Instruction for adding a new concrete IndexBuilder:
// 1. Create a subclass instantiated from IndexBuilder.
// 2. Add a new entry associated with that subclass in TableOptions::IndexType.
// 3. Add a create function for the new subclass in CreateIndexBuilder.
// Note: we can devise more advanced design to simplify the process for adding
// new subclass, which will, on the other hand, increase the code complexity and
// catch unwanted attention from readers. Given that we won't add/change
// indexes frequently, it makes sense to just embrace a more straightforward
// design that just works.
class IndexBuilder {
public:
// Index builder will construct a set of blocks which contain:
// 1. One primary index block.
// 2. (Optional) a set of metablocks that contains the metadata of the
// primary index.
struct IndexBlocks {
Slice index_block_contents;
std::unordered_map<std::string, Slice> meta_blocks;
};
explicit IndexBuilder(const Comparator* comparator)
: comparator_(comparator) {}
virtual ~IndexBuilder() {}
// Add a new index entry to index block.
// To allow further optimization, we provide `last_key_in_current_block` and
// `first_key_in_next_block`, based on which the specific implementation can
// determine the best index key to be used for the index block.
// @last_key_in_current_block: this parameter maybe overridden with the value
// "substitute key".
// @first_key_in_next_block: it will be nullptr if the entry being added is
// the last one in the table
//
// REQUIRES: Finish() has not yet been called.
virtual void AddIndexEntry(std::string* last_key_in_current_block,
const Slice* first_key_in_next_block,
const BlockHandle& block_handle) = 0;
// This method will be called whenever a key is added. The subclasses may
// override OnKeyAdded() if they need to collect additional information.
virtual void OnKeyAdded(const Slice& key) {}
// Inform the index builder that all entries has been written. Block builder
// may therefore perform any operation required for block finalization.
//
// REQUIRES: Finish() has not yet been called.
virtual Status Finish(IndexBlocks* index_blocks) = 0;
// Get the estimated size for index block.
virtual size_t EstimatedSize() const = 0;
protected:
const Comparator* comparator_;
};
// This index builder builds space-efficient index block.
//
// Optimizations:
// 1. Made block's `block_restart_interval` to be 1, which will avoid linear
// search when doing index lookup.
// 2. Shorten the key length for index block. Other than honestly using the
// last key in the data block as the index key, we instead find a shortest
// substitute key that serves the same function.
class ShortenedIndexBuilder : public IndexBuilder {
public:
explicit ShortenedIndexBuilder(const Comparator* comparator)
: IndexBuilder(comparator),
index_block_builder_(1 /* block_restart_interval == 1 */) {}
virtual void AddIndexEntry(std::string* last_key_in_current_block,
const Slice* first_key_in_next_block,
const BlockHandle& block_handle) override {
if (first_key_in_next_block != nullptr) {
comparator_->FindShortestSeparator(last_key_in_current_block,
*first_key_in_next_block);
} else {
comparator_->FindShortSuccessor(last_key_in_current_block);
}
std::string handle_encoding;
block_handle.EncodeTo(&handle_encoding);
index_block_builder_.Add(*last_key_in_current_block, handle_encoding);
}
virtual Status Finish(IndexBlocks* index_blocks) override {
index_blocks->index_block_contents = index_block_builder_.Finish();
return Status::OK();
}
virtual size_t EstimatedSize() const override {
return index_block_builder_.CurrentSizeEstimate();
}
private:
BlockBuilder index_block_builder_;
};
// HashIndexBuilder contains a binary-searchable primary index and the
// metadata for secondary hash index construction.
// The metadata for hash index consists two parts:
// - a metablock that compactly contains a sequence of prefixes. All prefixes
// are stored consectively without any metadata (like, prefix sizes) being
// stored, which is kept in the other metablock.
// - a metablock contains the metadata of the prefixes, including prefix size,
// restart index and number of block it spans. The format looks like:
//
// +-----------------+---------------------------+---------------------+ <=prefix 1
// | length: 4 bytes | restart interval: 4 bytes | num-blocks: 4 bytes |
// +-----------------+---------------------------+---------------------+ <=prefix 2
// | length: 4 bytes | restart interval: 4 bytes | num-blocks: 4 bytes |
// +-----------------+---------------------------+---------------------+
// | |
// | .... |
// | |
// +-----------------+---------------------------+---------------------+ <=prefix n
// | length: 4 bytes | restart interval: 4 bytes | num-blocks: 4 bytes |
// +-----------------+---------------------------+---------------------+
//
// The reason of separating these two metablocks is to enable the efficiently
// reuse the first metablock during hash index construction without unnecessary
// data copy or small heap allocations for prefixes.
class HashIndexBuilder : public IndexBuilder {
public:
explicit HashIndexBuilder(const Comparator* comparator,
const SliceTransform* hash_key_extractor)
: IndexBuilder(comparator),
primary_index_builder_(comparator),
hash_key_extractor_(hash_key_extractor) {}
virtual void AddIndexEntry(std::string* last_key_in_current_block,
const Slice* first_key_in_next_block,
const BlockHandle& block_handle) override {
++current_restart_index_;
primary_index_builder_.AddIndexEntry(last_key_in_current_block,
first_key_in_next_block, block_handle);
}
virtual void OnKeyAdded(const Slice& key) override {
auto key_prefix = hash_key_extractor_->Transform(key);
bool is_first_entry = pending_block_num_ == 0;
// Keys may share the prefix
if (is_first_entry || pending_entry_prefix_ != key_prefix) {
if (!is_first_entry) {
FlushPendingPrefix();
}
// need a hard copy otherwise the underlying data changes all the time.
// TODO(kailiu) ToString() is expensive. We may speed up can avoid data
// copy.
pending_entry_prefix_ = key_prefix.ToString();
pending_block_num_ = 1;
pending_entry_index_ = static_cast<uint32_t>(current_restart_index_);
} else {
// entry number increments when keys share the prefix reside in
// different data blocks.
auto last_restart_index = pending_entry_index_ + pending_block_num_ - 1;
assert(last_restart_index <= current_restart_index_);
if (last_restart_index != current_restart_index_) {
++pending_block_num_;
}
}
}
virtual Status Finish(IndexBlocks* index_blocks) override {
FlushPendingPrefix();
primary_index_builder_.Finish(index_blocks);
index_blocks->meta_blocks.insert(
{kHashIndexPrefixesBlock.c_str(), prefix_block_});
index_blocks->meta_blocks.insert(
{kHashIndexPrefixesMetadataBlock.c_str(), prefix_meta_block_});
return Status::OK();
}
virtual size_t EstimatedSize() const override {
return primary_index_builder_.EstimatedSize() + prefix_block_.size() +
prefix_meta_block_.size();
}
private:
void FlushPendingPrefix() {
prefix_block_.append(pending_entry_prefix_.data(),
pending_entry_prefix_.size());
PutVarint32(&prefix_meta_block_,
static_cast<uint32_t>(pending_entry_prefix_.size()));
PutVarint32(&prefix_meta_block_, pending_entry_index_);
PutVarint32(&prefix_meta_block_, pending_block_num_);
}
ShortenedIndexBuilder primary_index_builder_;
const SliceTransform* hash_key_extractor_;
// stores a sequence of prefixes
std::string prefix_block_;
// stores the metadata of prefixes
std::string prefix_meta_block_;
// The following 3 variables keeps unflushed prefix and its metadata.
// The details of block_num and entry_index can be found in
// "block_hash_index.{h,cc}"
uint32_t pending_block_num_ = 0;
uint32_t pending_entry_index_ = 0;
std::string pending_entry_prefix_;
uint64_t current_restart_index_ = 0;
};
// Without anonymous namespace here, we fail the warning -Wmissing-prototypes
namespace {
// Create a index builder based on its type.
IndexBuilder* CreateIndexBuilder(IndexType type, const Comparator* comparator,
const SliceTransform* prefix_extractor) {
switch (type) {
case BlockBasedTableOptions::kBinarySearch: {
return new ShortenedIndexBuilder(comparator);
}
case BlockBasedTableOptions::kHashSearch: {
return new HashIndexBuilder(comparator, prefix_extractor);
}
default: {
assert(!"Do not recognize the index type ");
return nullptr;
}
}
// impossible.
assert(false);
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.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);
}
// format_version is the block format as defined in include/rocksdb/table.h
Slice CompressBlock(const Slice& raw,
const CompressionOptions& compression_options,
CompressionType* type, uint32_t format_version,
std::string* compressed_output) {
if (*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 (*type) {
case kSnappyCompression:
if (Snappy_Compress(compression_options, 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_options,
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_options,
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_options,
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_options,
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 kZSTDNotFinalCompression:
if (ZSTD_Compress(compression_options, 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;
}
} // namespace
// 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 BlockBasedTableOptions table_options;
const InternalKeyComparator& internal_comparator;
WritableFileWriter* file;
uint64_t offset = 0;
Status status;
BlockBuilder data_block;
InternalKeySliceTransform internal_prefix_transform;
std::unique_ptr<IndexBuilder> index_builder;
std::string last_key;
const CompressionType compression_type;
const CompressionOptions compression_opts;
TableProperties props;
bool closed = false; // Either Finish() or Abandon() has been called.
std::unique_ptr<FilterBlockBuilder> filter_block;
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;
std::vector<std::unique_ptr<IntTblPropCollector>> table_properties_collectors;
Rep(const ImmutableCFOptions& _ioptions,
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)
: ioptions(_ioptions),
table_options(table_opt),
internal_comparator(icomparator),
file(f),
data_block(table_options.block_restart_interval,
table_options.use_delta_encoding),
internal_prefix_transform(_ioptions.prefix_extractor),
index_builder(CreateIndexBuilder(table_options.index_type,
&internal_comparator,
&this->internal_prefix_transform)),
compression_type(_compression_type),
compression_opts(_compression_opts),
filter_block(skip_filters ? nullptr : CreateFilterBlockBuilder(
_ioptions, table_options)),
flush_block_policy(
table_options.flush_block_policy_factory->NewFlushBlockPolicy(
table_options, data_block)) {
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,
_ioptions.prefix_extractor != nullptr));
}
};
BlockBasedTableBuilder::BlockBasedTableBuilder(
const ImmutableCFOptions& ioptions,
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) {
BlockBasedTableOptions sanitized_table_options(table_options);
if (sanitized_table_options.format_version == 0 &&
sanitized_table_options.checksum != kCRC32c) {
Log(InfoLogLevel::WARN_LEVEL, 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, sanitized_table_options, internal_comparator,
int_tbl_prop_collector_factories, column_family_id, file,
compression_type, compression_opts, skip_filters);
if (rep_->filter_block != nullptr) {
rep_->filter_block->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() {
assert(rep_->closed); // Catch errors where caller forgot to call Finish()
delete rep_;
}
void BlockBasedTableBuilder::Add(const Slice& key, const Slice& value) {
Rep* r = rep_;
assert(!r->closed);
if (!ok()) return;
if (r->props.num_entries > 0) {
assert(r->internal_comparator.Compare(key, Slice(r->last_key)) > 0);
}
auto should_flush = r->flush_block_policy->Update(key, value);
if (should_flush) {
assert(!r->data_block.empty());
Flush();
// 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->index_builder->AddIndexEntry(&r->last_key, &key, r->pending_handle);
}
}
if (r->filter_block != nullptr) {
r->filter_block->Add(ExtractUserKey(key));
}
r->last_key.assign(key.data(), key.size());
r->data_block.Add(key, value);
r->props.num_entries++;
r->props.raw_key_size += key.size();
r->props.raw_value_size += value.size();
r->index_builder->OnKeyAdded(key);
NotifyCollectTableCollectorsOnAdd(key, value, r->offset,
r->table_properties_collectors,
r->ioptions.info_log);
}
void BlockBasedTableBuilder::Flush() {
Rep* r = rep_;
assert(!r->closed);
if (!ok()) return;
if (r->data_block.empty()) return;
WriteBlock(&r->data_block, &r->pending_handle);
if (ok() && !r->table_options.skip_table_builder_flush) {
r->status = r->file->Flush();
}
if (r->filter_block != nullptr) {
r->filter_block->StartBlock(r->offset);
}
r->props.data_size = r->offset;
++r->props.num_data_blocks;
}
void BlockBasedTableBuilder::WriteBlock(BlockBuilder* block,
BlockHandle* handle) {
WriteBlock(block->Finish(), handle);
block->Reset();
}
void BlockBasedTableBuilder::WriteBlock(const Slice& raw_block_contents,
BlockHandle* handle) {
// 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;
if (raw_block_contents.size() < kCompressionSizeLimit) {
block_contents =
CompressBlock(raw_block_contents, r->compression_opts, &type,
r->table_options.format_version, &r->compressed_output);
} else {
RecordTick(r->ioptions.statistics, NUMBER_BLOCK_NOT_COMPRESSED);
type = kNoCompression;
block_contents = raw_block_contents;
}
WriteRawBlock(block_contents, type, handle);
r->compressed_output.clear();
}
void BlockBasedTableBuilder::WriteRawBlock(const Slice& block_contents,
CompressionType type,
BlockHandle* handle) {
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());
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:
// we don't support no checksum yet
assert(false);
// intentional fallthrough in release binary
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;
}
}
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;
}
}
}
Status BlockBasedTableBuilder::status() const {
return rep_->status;
}
static void DeleteCachedBlock(const Slice& key, void* value) {
Block* block = reinterpret_cast<Block*>(value);
delete block;
}
//
// 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) {
Cache::Handle* cache_handle = nullptr;
size_t size = block_contents.size();
std::unique_ptr<char[]> ubuf(new char[size + 1]);
memcpy(ubuf.get(), block_contents.data(), size);
ubuf[size] = type;
BlockContents results(std::move(ubuf), size, true, type);
Block* block = new Block(std::move(results));
// 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.
cache_handle = block_cache_compressed->Insert(
key, block, block->usable_size(), &DeleteCachedBlock);
block_cache_compressed->Release(cache_handle);
// Invalidate OS cache.
r->file->InvalidateCache(static_cast<size_t>(r->offset), size);
}
return Status::OK();
}
Status BlockBasedTableBuilder::Finish() {
Rep* r = rep_;
bool empty_data_block = r->data_block.empty();
Flush();
assert(!r->closed);
r->closed = true;
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();
r->props.filter_size = filter_contents.size();
WriteRawBlock(filter_contents, kNoCompression, &filter_block_handle);
}
// To make sure properties block is able to keep the accurate size of index
// block, we will finish writing all index entries here and flush them
// to storage after metaindex block is written.
if (ok() && !empty_data_block) {
r->index_builder->AddIndexEntry(
&r->last_key, nullptr /* no next data block */, r->pending_handle);
}
IndexBuilder::IndexBlocks index_blocks;
auto s = r->index_builder->Finish(&index_blocks);
if (!s.ok()) {
return s;
}
// Write meta blocks and metaindex block with the following order.
// 1. [meta block: filter]
// 2. [other meta blocks]
// 3. [meta block: properties]
// 4. [metaindex block]
// write meta blocks
MetaIndexBuilder meta_index_builder;
for (const auto& item : index_blocks.meta_blocks) {
BlockHandle block_handle;
WriteBlock(item.second, &block_handle);
meta_index_builder.Add(item.first, block_handle);
}
if (ok()) {
if (r->filter_block != nullptr) {
// Add mapping from "<filter_block_prefix>.Name" to location
// of filter data.
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);
}
// Write properties block.
{
PropertyBlockBuilder property_block_builder;
r->props.filter_policy_name = r->table_options.filter_policy != nullptr ?
r->table_options.filter_policy->Name() : "";
r->props.index_size =
r->index_builder->EstimatedSize() + kBlockTrailerSize;
// Add basic properties
property_block_builder.AddTableProperty(r->props);
// Add use collected properties
NotifyCollectTableCollectorsOnFinish(r->table_properties_collectors,
r->ioptions.info_log,
&property_block_builder);
BlockHandle properties_block_handle;
WriteRawBlock(
property_block_builder.Finish(),
kNoCompression,
&properties_block_handle
);
meta_index_builder.Add(kPropertiesBlock, properties_block_handle);
} // end of properties block writing
} // meta blocks
// Write index block
if (ok()) {
// flush the meta index block
WriteRawBlock(meta_index_builder.Finish(), kNoCompression,
&metaindex_block_handle);
WriteBlock(index_blocks.index_block_contents, &index_block_handle);
}
// Write footer
if (ok()) {
// 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);
r->status = r->file->Append(footer_encoding);
if (r->status.ok()) {
r->offset += footer_encoding.size();
}
}
return r->status;
}
void BlockBasedTableBuilder::Abandon() {
Rep* r = rep_;
assert(!r->closed);
r->closed = true;
}
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.";
} // namespace rocksdb
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