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rocksdb/table/block_based/block_based_table_reader.cc
sdong b931f84e56 Divide file_reader_writer.h and .cc (#5803) 
Summary:
file_reader_writer.h and .cc contain several files and helper function, and it's hard to navigate. Separate it to multiple files and put them under file/
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5803

Test Plan: Build whole project using make and cmake.

Differential Revision: D17374550

fbshipit-source-id: 10efca907721e7a78ed25bbf74dc5410dea05987
2019-09-16 10:33:51 -07:00

4351 lines
162 KiB
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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/block_based_table_reader.h"
#include <algorithm>
#include <array>
#include <limits>
#include <string>
#include <utility>
#include <vector>
#include "db/dbformat.h"
#include "db/pinned_iterators_manager.h"
#include "file/file_prefetch_buffer.h"
#include "file/random_access_file_reader.h"
#include "rocksdb/cache.h"
#include "rocksdb/comparator.h"
#include "rocksdb/env.h"
#include "rocksdb/filter_policy.h"
#include "rocksdb/iterator.h"
#include "rocksdb/options.h"
#include "rocksdb/statistics.h"
#include "rocksdb/table.h"
#include "rocksdb/table_properties.h"
#include "table/block_based/block.h"
#include "table/block_based/block_based_filter_block.h"
#include "table/block_based/block_based_table_factory.h"
#include "table/block_based/block_prefix_index.h"
#include "table/block_based/filter_block.h"
#include "table/block_based/full_filter_block.h"
#include "table/block_based/partitioned_filter_block.h"
#include "table/block_fetcher.h"
#include "table/format.h"
#include "table/get_context.h"
#include "table/internal_iterator.h"
#include "table/meta_blocks.h"
#include "table/multiget_context.h"
#include "table/persistent_cache_helper.h"
#include "table/sst_file_writer_collectors.h"
#include "table/two_level_iterator.h"
#include "monitoring/perf_context_imp.h"
#include "test_util/sync_point.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/stop_watch.h"
#include "util/string_util.h"
#include "util/xxhash.h"
namespace rocksdb {
extern const uint64_t kBlockBasedTableMagicNumber;
extern const std::string kHashIndexPrefixesBlock;
extern const std::string kHashIndexPrefixesMetadataBlock;
typedef BlockBasedTable::IndexReader IndexReader;
// Found that 256 KB readahead size provides the best performance, based on
// experiments, for auto readahead. Experiment data is in PR #3282.
const size_t BlockBasedTable::kMaxAutoReadaheadSize = 256 * 1024;
BlockBasedTable::~BlockBasedTable() {
delete rep_;
}
std::atomic<uint64_t> BlockBasedTable::next_cache_key_id_(0);
template <typename TBlocklike>
class BlocklikeTraits;
template <>
class BlocklikeTraits<BlockContents> {
public:
static BlockContents* Create(BlockContents&& contents,
SequenceNumber /* global_seqno */,
size_t /* read_amp_bytes_per_bit */,
Statistics* /* statistics */,
bool /* using_zstd */) {
return new BlockContents(std::move(contents));
}
static uint32_t GetNumRestarts(const BlockContents& /* contents */) {
return 0;
}
};
template <>
class BlocklikeTraits<Block> {
public:
static Block* Create(BlockContents&& contents, SequenceNumber global_seqno,
size_t read_amp_bytes_per_bit, Statistics* statistics,
bool /* using_zstd */) {
return new Block(std::move(contents), global_seqno, read_amp_bytes_per_bit,
statistics);
}
static uint32_t GetNumRestarts(const Block& block) {
return block.NumRestarts();
}
};
template <>
class BlocklikeTraits<UncompressionDict> {
public:
static UncompressionDict* Create(BlockContents&& contents,
SequenceNumber /* global_seqno */,
size_t /* read_amp_bytes_per_bit */,
Statistics* /* statistics */,
bool using_zstd) {
return new UncompressionDict(contents.data, std::move(contents.allocation),
using_zstd);
}
static uint32_t GetNumRestarts(const UncompressionDict& /* dict */) {
return 0;
}
};
namespace {
// Read the block identified by "handle" from "file".
// The only relevant option is options.verify_checksums for now.
// On failure return non-OK.
// On success fill *result and return OK - caller owns *result
// @param uncompression_dict Data for presetting the compression library's
// dictionary.
template <typename TBlocklike>
Status ReadBlockFromFile(
RandomAccessFileReader* file, FilePrefetchBuffer* prefetch_buffer,
const Footer& footer, const ReadOptions& options, const BlockHandle& handle,
std::unique_ptr<TBlocklike>* result, const ImmutableCFOptions& ioptions,
bool do_uncompress, bool maybe_compressed, BlockType block_type,
const UncompressionDict& uncompression_dict,
const PersistentCacheOptions& cache_options, SequenceNumber global_seqno,
size_t read_amp_bytes_per_bit, MemoryAllocator* memory_allocator,
bool for_compaction, bool using_zstd) {
assert(result);
BlockContents contents;
BlockFetcher block_fetcher(
file, prefetch_buffer, footer, options, handle, &contents, ioptions,
do_uncompress, maybe_compressed, block_type, uncompression_dict,
cache_options, memory_allocator, nullptr, for_compaction);
Status s = block_fetcher.ReadBlockContents();
if (s.ok()) {
result->reset(BlocklikeTraits<TBlocklike>::Create(
std::move(contents), global_seqno, read_amp_bytes_per_bit,
ioptions.statistics, using_zstd));
}
return s;
}
inline MemoryAllocator* GetMemoryAllocator(
const BlockBasedTableOptions& table_options) {
return table_options.block_cache.get()
? table_options.block_cache->memory_allocator()
: nullptr;
}
inline MemoryAllocator* GetMemoryAllocatorForCompressedBlock(
const BlockBasedTableOptions& table_options) {
return table_options.block_cache_compressed.get()
? table_options.block_cache_compressed->memory_allocator()
: nullptr;
}
// Delete the entry resided in the cache.
template <class Entry>
void DeleteCachedEntry(const Slice& /*key*/, void* value) {
auto entry = reinterpret_cast<Entry*>(value);
delete entry;
}
// Release the cached entry and decrement its ref count.
void ForceReleaseCachedEntry(void* arg, void* h) {
Cache* cache = reinterpret_cast<Cache*>(arg);
Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
cache->Release(handle, true /* force_erase */);
}
// Release the cached entry and decrement its ref count.
// Do not force erase
void ReleaseCachedEntry(void* arg, void* h) {
Cache* cache = reinterpret_cast<Cache*>(arg);
Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
cache->Release(handle, false /* force_erase */);
}
// For hash based index, return true if prefix_extractor and
// prefix_extractor_block mismatch, false otherwise. This flag will be used
// as total_order_seek via NewIndexIterator
bool PrefixExtractorChanged(const TableProperties* table_properties,
const SliceTransform* prefix_extractor) {
// BlockBasedTableOptions::kHashSearch requires prefix_extractor to be set.
// Turn off hash index in prefix_extractor is not set; if prefix_extractor
// is set but prefix_extractor_block is not set, also disable hash index
if (prefix_extractor == nullptr || table_properties == nullptr ||
table_properties->prefix_extractor_name.empty()) {
return true;
}
// prefix_extractor and prefix_extractor_block are both non-empty
if (table_properties->prefix_extractor_name.compare(
prefix_extractor->Name()) != 0) {
return true;
} else {
return false;
}
}
CacheAllocationPtr CopyBufferToHeap(MemoryAllocator* allocator, Slice& buf) {
CacheAllocationPtr heap_buf;
heap_buf = AllocateBlock(buf.size(), allocator);
memcpy(heap_buf.get(), buf.data(), buf.size());
return heap_buf;
}
} // namespace
// Encapsulates common functionality for the various index reader
// implementations. Provides access to the index block regardless of whether
// it is owned by the reader or stored in the cache, or whether it is pinned
// in the cache or not.
class BlockBasedTable::IndexReaderCommon : public BlockBasedTable::IndexReader {
public:
IndexReaderCommon(const BlockBasedTable* t,
CachableEntry<Block>&& index_block)
: table_(t), index_block_(std::move(index_block)) {
assert(table_ != nullptr);
}
protected:
static Status ReadIndexBlock(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer,
const ReadOptions& read_options, bool use_cache,
GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block);
const BlockBasedTable* table() const { return table_; }
const InternalKeyComparator* internal_comparator() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return &table_->get_rep()->internal_comparator;
}
bool index_has_first_key() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_has_first_key;
}
bool index_key_includes_seq() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_key_includes_seq;
}
bool index_value_is_full() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_value_is_full;
}
bool cache_index_blocks() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->table_options.cache_index_and_filter_blocks;
}
Status GetOrReadIndexBlock(bool no_io, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) const;
size_t ApproximateIndexBlockMemoryUsage() const {
assert(!index_block_.GetOwnValue() || index_block_.GetValue() != nullptr);
return index_block_.GetOwnValue()
? index_block_.GetValue()->ApproximateMemoryUsage()
: 0;
}
private:
const BlockBasedTable* table_;
CachableEntry<Block> index_block_;
};
Status BlockBasedTable::IndexReaderCommon::ReadIndexBlock(
const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
const ReadOptions& read_options, bool use_cache, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) {
PERF_TIMER_GUARD(read_index_block_nanos);
assert(table != nullptr);
assert(index_block != nullptr);
assert(index_block->IsEmpty());
const Rep* const rep = table->get_rep();
assert(rep != nullptr);
const Status s = table->RetrieveBlock(
prefetch_buffer, read_options, rep->footer.index_handle(),
UncompressionDict::GetEmptyDict(), index_block, BlockType::kIndex,
get_context, lookup_context, /* for_compaction */ false, use_cache);
return s;
}
Status BlockBasedTable::IndexReaderCommon::GetOrReadIndexBlock(
bool no_io, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) const {
assert(index_block != nullptr);
if (!index_block_.IsEmpty()) {
index_block->SetUnownedValue(index_block_.GetValue());
return Status::OK();
}
ReadOptions read_options;
if (no_io) {
read_options.read_tier = kBlockCacheTier;
}
return ReadIndexBlock(table_, /*prefetch_buffer=*/nullptr, read_options,
cache_index_blocks(), get_context, lookup_context,
index_block);
}
// Index that allows binary search lookup in a two-level index structure.
class PartitionIndexReader : public BlockBasedTable::IndexReaderCommon {
public:
// Read the partition index from the file and create an instance for
// `PartitionIndexReader`.
// On success, index_reader will be populated; otherwise it will remain
// unmodified.
static Status Create(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer, bool use_cache,
bool prefetch, bool pin,
BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
assert(table != nullptr);
assert(table->get_rep());
assert(!pin || prefetch);
assert(index_reader != nullptr);
CachableEntry<Block> index_block;
if (prefetch || !use_cache) {
const Status s =
ReadIndexBlock(table, prefetch_buffer, ReadOptions(), use_cache,
/*get_context=*/nullptr, lookup_context, &index_block);
if (!s.ok()) {
return s;
}
if (use_cache && !pin) {
index_block.Reset();
}
}
index_reader->reset(
new PartitionIndexReader(table, std::move(index_block)));
return Status::OK();
}
// return a two-level iterator: first level is on the partition index
InternalIteratorBase<IndexValue>* NewIterator(
const ReadOptions& read_options, bool /* disable_prefix_seek */,
IndexBlockIter* iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) override {
const bool no_io = (read_options.read_tier == kBlockCacheTier);
CachableEntry<Block> index_block;
const Status s =
GetOrReadIndexBlock(no_io, get_context, lookup_context, &index_block);
if (!s.ok()) {
if (iter != nullptr) {
iter->Invalidate(s);
return iter;
}
return NewErrorInternalIterator<IndexValue>(s);
}
InternalIteratorBase<IndexValue>* it = nullptr;
Statistics* kNullStats = nullptr;
// Filters are already checked before seeking the index
if (!partition_map_.empty()) {
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
it = NewTwoLevelIterator(
new BlockBasedTable::PartitionedIndexIteratorState(table(),
&partition_map_),
index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(),
nullptr, kNullStats, true, index_has_first_key(),
index_key_includes_seq(), index_value_is_full()));
} else {
ReadOptions ro;
ro.fill_cache = read_options.fill_cache;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
it = new BlockBasedTableIterator<IndexBlockIter, IndexValue>(
table(), ro, *internal_comparator(),
index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(),
nullptr, kNullStats, true, index_has_first_key(),
index_key_includes_seq(), index_value_is_full()),
false, true, /* prefix_extractor */ nullptr, BlockType::kIndex,
lookup_context ? lookup_context->caller
: TableReaderCaller::kUncategorized);
}
assert(it != nullptr);
index_block.TransferTo(it);
return it;
// TODO(myabandeh): Update TwoLevelIterator to be able to make use of
// on-stack BlockIter while the state is on heap. Currentlly it assumes
// the first level iter is always on heap and will attempt to delete it
// in its destructor.
}
void CacheDependencies(bool pin) override {
// Before read partitions, prefetch them to avoid lots of IOs
BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
const BlockBasedTable::Rep* rep = table()->rep_;
IndexBlockIter biter;
BlockHandle handle;
Statistics* kNullStats = nullptr;
CachableEntry<Block> index_block;
Status s = GetOrReadIndexBlock(false /* no_io */, nullptr /* get_context */,
&lookup_context, &index_block);
if (!s.ok()) {
ROCKS_LOG_WARN(rep->ioptions.info_log,
"Error retrieving top-level index block while trying to "
"cache index partitions: %s",
s.ToString().c_str());
return;
}
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(), &biter,
kNullStats, true, index_has_first_key(), index_key_includes_seq(),
index_value_is_full());
// Index partitions are assumed to be consecuitive. Prefetch them all.
// Read the first block offset
biter.SeekToFirst();
if (!biter.Valid()) {
// Empty index.
return;
}
handle = biter.value().handle;
uint64_t prefetch_off = handle.offset();
// Read the last block's offset
biter.SeekToLast();
if (!biter.Valid()) {
// Empty index.
return;
}
handle = biter.value().handle;
uint64_t last_off = handle.offset() + handle.size() + kBlockTrailerSize;
uint64_t prefetch_len = last_off - prefetch_off;
std::unique_ptr<FilePrefetchBuffer> prefetch_buffer;
auto& file = rep->file;
prefetch_buffer.reset(new FilePrefetchBuffer());
s = prefetch_buffer->Prefetch(file.get(), prefetch_off,
static_cast<size_t>(prefetch_len));
// After prefetch, read the partitions one by one
biter.SeekToFirst();
auto ro = ReadOptions();
for (; biter.Valid(); biter.Next()) {
handle = biter.value().handle;
CachableEntry<Block> block;
// TODO: Support counter batch update for partitioned index and
// filter blocks
s = table()->MaybeReadBlockAndLoadToCache(
prefetch_buffer.get(), ro, handle, UncompressionDict::GetEmptyDict(),
&block, BlockType::kIndex, /*get_context=*/nullptr, &lookup_context,
/*contents=*/nullptr);
assert(s.ok() || block.GetValue() == nullptr);
if (s.ok() && block.GetValue() != nullptr) {
if (block.IsCached()) {
if (pin) {
partition_map_[handle.offset()] = std::move(block);
}
}
}
}
}
size_t ApproximateMemoryUsage() const override {
size_t usage = ApproximateIndexBlockMemoryUsage();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size(const_cast<PartitionIndexReader*>(this));
#else
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
// TODO(myabandeh): more accurate estimate of partition_map_ mem usage
return usage;
}
private:
PartitionIndexReader(const BlockBasedTable* t,
CachableEntry<Block>&& index_block)
: IndexReaderCommon(t, std::move(index_block)) {}
std::unordered_map<uint64_t, CachableEntry<Block>> partition_map_;
};
// Index that allows binary search lookup for the first key of each block.
// This class can be viewed as a thin wrapper for `Block` class which already
// supports binary search.
class BinarySearchIndexReader : public BlockBasedTable::IndexReaderCommon {
public:
// Read index from the file and create an intance for
// `BinarySearchIndexReader`.
// On success, index_reader will be populated; otherwise it will remain
// unmodified.
static Status Create(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer, bool use_cache,
bool prefetch, bool pin,
BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
assert(table != nullptr);
assert(table->get_rep());
assert(!pin || prefetch);
assert(index_reader != nullptr);
CachableEntry<Block> index_block;
if (prefetch || !use_cache) {
const Status s =
ReadIndexBlock(table, prefetch_buffer, ReadOptions(), use_cache,
/*get_context=*/nullptr, lookup_context, &index_block);
if (!s.ok()) {
return s;
}
if (use_cache && !pin) {
index_block.Reset();
}
}
index_reader->reset(
new BinarySearchIndexReader(table, std::move(index_block)));
return Status::OK();
}
InternalIteratorBase<IndexValue>* NewIterator(
const ReadOptions& read_options, bool /* disable_prefix_seek */,
IndexBlockIter* iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) override {
const bool no_io = (read_options.read_tier == kBlockCacheTier);
CachableEntry<Block> index_block;
const Status s =
GetOrReadIndexBlock(no_io, get_context, lookup_context, &index_block);
if (!s.ok()) {
if (iter != nullptr) {
iter->Invalidate(s);
return iter;
}
return NewErrorInternalIterator<IndexValue>(s);
}
Statistics* kNullStats = nullptr;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
auto it = index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(), iter,
kNullStats, true, index_has_first_key(), index_key_includes_seq(),
index_value_is_full());
assert(it != nullptr);
index_block.TransferTo(it);
return it;
}
size_t ApproximateMemoryUsage() const override {
size_t usage = ApproximateIndexBlockMemoryUsage();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size(const_cast<BinarySearchIndexReader*>(this));
#else
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
return usage;
}
private:
BinarySearchIndexReader(const BlockBasedTable* t,
CachableEntry<Block>&& index_block)
: IndexReaderCommon(t, std::move(index_block)) {}
};
// Index that leverages an internal hash table to quicken the lookup for a given
// key.
class HashIndexReader : public BlockBasedTable::IndexReaderCommon {
public:
static Status Create(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer,
InternalIterator* meta_index_iter, bool use_cache,
bool prefetch, bool pin,
BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
assert(table != nullptr);
assert(index_reader != nullptr);
assert(!pin || prefetch);
const BlockBasedTable::Rep* rep = table->get_rep();
assert(rep != nullptr);
CachableEntry<Block> index_block;
if (prefetch || !use_cache) {
const Status s =
ReadIndexBlock(table, prefetch_buffer, ReadOptions(), use_cache,
/*get_context=*/nullptr, lookup_context, &index_block);
if (!s.ok()) {
return s;
}
if (use_cache && !pin) {
index_block.Reset();
}
}
// Note, failure to create prefix hash index does not need to be a
// hard error. We can still fall back to the original binary search index.
// So, Create will succeed regardless, from this point on.
index_reader->reset(new HashIndexReader(table, std::move(index_block)));
// Get prefixes block
BlockHandle prefixes_handle;
Status s = FindMetaBlock(meta_index_iter, kHashIndexPrefixesBlock,
&prefixes_handle);
if (!s.ok()) {
// TODO: log error
return Status::OK();
}
// Get index metadata block
BlockHandle prefixes_meta_handle;
s = FindMetaBlock(meta_index_iter, kHashIndexPrefixesMetadataBlock,
&prefixes_meta_handle);
if (!s.ok()) {
// TODO: log error
return Status::OK();
}
RandomAccessFileReader* const file = rep->file.get();
const Footer& footer = rep->footer;
const ImmutableCFOptions& ioptions = rep->ioptions;
const PersistentCacheOptions& cache_options = rep->persistent_cache_options;
MemoryAllocator* const memory_allocator =
GetMemoryAllocator(rep->table_options);
// Read contents for the blocks
BlockContents prefixes_contents;
BlockFetcher prefixes_block_fetcher(
file, prefetch_buffer, footer, ReadOptions(), prefixes_handle,
&prefixes_contents, ioptions, true /*decompress*/,
true /*maybe_compressed*/, BlockType::kHashIndexPrefixes,
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
s = prefixes_block_fetcher.ReadBlockContents();
if (!s.ok()) {
return s;
}
BlockContents prefixes_meta_contents;
BlockFetcher prefixes_meta_block_fetcher(
file, prefetch_buffer, footer, ReadOptions(), prefixes_meta_handle,
&prefixes_meta_contents, ioptions, true /*decompress*/,
true /*maybe_compressed*/, BlockType::kHashIndexMetadata,
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
s = prefixes_meta_block_fetcher.ReadBlockContents();
if (!s.ok()) {
// TODO: log error
return Status::OK();
}
BlockPrefixIndex* prefix_index = nullptr;
s = BlockPrefixIndex::Create(rep->internal_prefix_transform.get(),
prefixes_contents.data,
prefixes_meta_contents.data, &prefix_index);
// TODO: log error
if (s.ok()) {
HashIndexReader* const hash_index_reader =
static_cast<HashIndexReader*>(index_reader->get());
hash_index_reader->prefix_index_.reset(prefix_index);
}
return Status::OK();
}
InternalIteratorBase<IndexValue>* NewIterator(
const ReadOptions& read_options, bool disable_prefix_seek,
IndexBlockIter* iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) override {
const bool no_io = (read_options.read_tier == kBlockCacheTier);
CachableEntry<Block> index_block;
const Status s =
GetOrReadIndexBlock(no_io, get_context, lookup_context, &index_block);
if (!s.ok()) {
if (iter != nullptr) {
iter->Invalidate(s);
return iter;
}
return NewErrorInternalIterator<IndexValue>(s);
}
Statistics* kNullStats = nullptr;
const bool total_order_seek =
read_options.total_order_seek || disable_prefix_seek;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
auto it = index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(), iter,
kNullStats, total_order_seek, index_has_first_key(),
index_key_includes_seq(), index_value_is_full(),
false /* block_contents_pinned */, prefix_index_.get());
assert(it != nullptr);
index_block.TransferTo(it);
return it;
}
size_t ApproximateMemoryUsage() const override {
size_t usage = ApproximateIndexBlockMemoryUsage();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size(const_cast<HashIndexReader*>(this));
#else
if (prefix_index_) {
usage += prefix_index_->ApproximateMemoryUsage();
}
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
return usage;
}
private:
HashIndexReader(const BlockBasedTable* t, CachableEntry<Block>&& index_block)
: IndexReaderCommon(t, std::move(index_block)) {}
std::unique_ptr<BlockPrefixIndex> prefix_index_;
};
void BlockBasedTable::UpdateCacheHitMetrics(BlockType block_type,
GetContext* get_context,
size_t usage) const {
Statistics* const statistics = rep_->ioptions.statistics;
PERF_COUNTER_ADD(block_cache_hit_count, 1);
PERF_COUNTER_BY_LEVEL_ADD(block_cache_hit_count, 1,
static_cast<uint32_t>(rep_->level));
if (get_context) {
++get_context->get_context_stats_.num_cache_hit;
get_context->get_context_stats_.num_cache_bytes_read += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_HIT);
RecordTick(statistics, BLOCK_CACHE_BYTES_READ, usage);
}
switch (block_type) {
case BlockType::kFilter:
PERF_COUNTER_ADD(block_cache_filter_hit_count, 1);
if (get_context) {
++get_context->get_context_stats_.num_cache_filter_hit;
} else {
RecordTick(statistics, BLOCK_CACHE_FILTER_HIT);
}
break;
case BlockType::kCompressionDictionary:
// TODO: introduce perf counter for compression dictionary hit count
if (get_context) {
++get_context->get_context_stats_.num_cache_compression_dict_hit;
} else {
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_HIT);
}
break;
case BlockType::kIndex:
PERF_COUNTER_ADD(block_cache_index_hit_count, 1);
if (get_context) {
++get_context->get_context_stats_.num_cache_index_hit;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_HIT);
}
break;
default:
// TODO: introduce dedicated tickers/statistics/counters
// for range tombstones
if (get_context) {
++get_context->get_context_stats_.num_cache_data_hit;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_HIT);
}
break;
}
}
void BlockBasedTable::UpdateCacheMissMetrics(BlockType block_type,
GetContext* get_context) const {
Statistics* const statistics = rep_->ioptions.statistics;
// TODO: introduce aggregate (not per-level) block cache miss count
PERF_COUNTER_BY_LEVEL_ADD(block_cache_miss_count, 1,
static_cast<uint32_t>(rep_->level));
if (get_context) {
++get_context->get_context_stats_.num_cache_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_MISS);
}
// TODO: introduce perf counters for misses per block type
switch (block_type) {
case BlockType::kFilter:
if (get_context) {
++get_context->get_context_stats_.num_cache_filter_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_FILTER_MISS);
}
break;
case BlockType::kCompressionDictionary:
if (get_context) {
++get_context->get_context_stats_.num_cache_compression_dict_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_MISS);
}
break;
case BlockType::kIndex:
if (get_context) {
++get_context->get_context_stats_.num_cache_index_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_MISS);
}
break;
default:
// TODO: introduce dedicated tickers/statistics/counters
// for range tombstones
if (get_context) {
++get_context->get_context_stats_.num_cache_data_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_MISS);
}
break;
}
}
void BlockBasedTable::UpdateCacheInsertionMetrics(BlockType block_type,
GetContext* get_context,
size_t usage) const {
Statistics* const statistics = rep_->ioptions.statistics;
// TODO: introduce perf counters for block cache insertions
if (get_context) {
++get_context->get_context_stats_.num_cache_add;
get_context->get_context_stats_.num_cache_bytes_write += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_ADD);
RecordTick(statistics, BLOCK_CACHE_BYTES_WRITE, usage);
}
switch (block_type) {
case BlockType::kFilter:
if (get_context) {
++get_context->get_context_stats_.num_cache_filter_add;
get_context->get_context_stats_.num_cache_filter_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_FILTER_ADD);
RecordTick(statistics, BLOCK_CACHE_FILTER_BYTES_INSERT, usage);
}
break;
case BlockType::kCompressionDictionary:
if (get_context) {
++get_context->get_context_stats_.num_cache_compression_dict_add;
get_context->get_context_stats_
.num_cache_compression_dict_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_ADD);
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_BYTES_INSERT,
usage);
}
break;
case BlockType::kIndex:
if (get_context) {
++get_context->get_context_stats_.num_cache_index_add;
get_context->get_context_stats_.num_cache_index_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_ADD);
RecordTick(statistics, BLOCK_CACHE_INDEX_BYTES_INSERT, usage);
}
break;
default:
// TODO: introduce dedicated tickers/statistics/counters
// for range tombstones
if (get_context) {
++get_context->get_context_stats_.num_cache_data_add;
get_context->get_context_stats_.num_cache_data_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_ADD);
RecordTick(statistics, BLOCK_CACHE_DATA_BYTES_INSERT, usage);
}
break;
}
}
Cache::Handle* BlockBasedTable::GetEntryFromCache(
Cache* block_cache, const Slice& key, BlockType block_type,
GetContext* get_context) const {
auto cache_handle = block_cache->Lookup(key, rep_->ioptions.statistics);
if (cache_handle != nullptr) {
UpdateCacheHitMetrics(block_type, get_context,
block_cache->GetUsage(cache_handle));
} else {
UpdateCacheMissMetrics(block_type, get_context);
}
return cache_handle;
}
// Helper function to setup the cache key's prefix for the Table.
void BlockBasedTable::SetupCacheKeyPrefix(Rep* rep) {
assert(kMaxCacheKeyPrefixSize >= 10);
rep->cache_key_prefix_size = 0;
rep->compressed_cache_key_prefix_size = 0;
if (rep->table_options.block_cache != nullptr) {
GenerateCachePrefix(rep->table_options.block_cache.get(), rep->file->file(),
&rep->cache_key_prefix[0], &rep->cache_key_prefix_size);
}
if (rep->table_options.persistent_cache != nullptr) {
GenerateCachePrefix(/*cache=*/nullptr, rep->file->file(),
&rep->persistent_cache_key_prefix[0],
&rep->persistent_cache_key_prefix_size);
}
if (rep->table_options.block_cache_compressed != nullptr) {
GenerateCachePrefix(rep->table_options.block_cache_compressed.get(),
rep->file->file(), &rep->compressed_cache_key_prefix[0],
&rep->compressed_cache_key_prefix_size);
}
}
void BlockBasedTable::GenerateCachePrefix(Cache* cc, RandomAccessFile* file,
char* buffer, size_t* size) {
// generate an id from the file
*size = file->GetUniqueId(buffer, kMaxCacheKeyPrefixSize);
// If the prefix wasn't generated or was too long,
// create one from the cache.
if (cc && *size == 0) {
char* end = EncodeVarint64(buffer, cc->NewId());
*size = static_cast<size_t>(end - buffer);
}
}
void BlockBasedTable::GenerateCachePrefix(Cache* cc, WritableFile* file,
char* buffer, size_t* size) {
// generate an id from the file
*size = file->GetUniqueId(buffer, kMaxCacheKeyPrefixSize);
// If the prefix wasn't generated or was too long,
// create one from the cache.
if (*size == 0) {
char* end = EncodeVarint64(buffer, cc->NewId());
*size = static_cast<size_t>(end - buffer);
}
}
namespace {
// Return True if table_properties has `user_prop_name` has a `true` value
// or it doesn't contain this property (for backward compatible).
bool IsFeatureSupported(const TableProperties& table_properties,
const std::string& user_prop_name, Logger* info_log) {
auto& props = table_properties.user_collected_properties;
auto pos = props.find(user_prop_name);
// Older version doesn't have this value set. Skip this check.
if (pos != props.end()) {
if (pos->second == kPropFalse) {
return false;
} else if (pos->second != kPropTrue) {
ROCKS_LOG_WARN(info_log, "Property %s has invalidate value %s",
user_prop_name.c_str(), pos->second.c_str());
}
}
return true;
}
// Caller has to ensure seqno is not nullptr.
Status GetGlobalSequenceNumber(const TableProperties& table_properties,
SequenceNumber largest_seqno,
SequenceNumber* seqno) {
const auto& props = table_properties.user_collected_properties;
const auto version_pos = props.find(ExternalSstFilePropertyNames::kVersion);
const auto seqno_pos = props.find(ExternalSstFilePropertyNames::kGlobalSeqno);
*seqno = kDisableGlobalSequenceNumber;
if (version_pos == props.end()) {
if (seqno_pos != props.end()) {
std::array<char, 200> msg_buf;
// This is not an external sst file, global_seqno is not supported.
snprintf(
msg_buf.data(), msg_buf.max_size(),
"A non-external sst file have global seqno property with value %s",
seqno_pos->second.c_str());
return Status::Corruption(msg_buf.data());
}
return Status::OK();
}
uint32_t version = DecodeFixed32(version_pos->second.c_str());
if (version < 2) {
if (seqno_pos != props.end() || version != 1) {
std::array<char, 200> msg_buf;
// This is a v1 external sst file, global_seqno is not supported.
snprintf(msg_buf.data(), msg_buf.max_size(),
"An external sst file with version %u have global seqno "
"property with value %s",
version, seqno_pos->second.c_str());
return Status::Corruption(msg_buf.data());
}
return Status::OK();
}
// Since we have a plan to deprecate global_seqno, we do not return failure
// if seqno_pos == props.end(). We rely on version_pos to detect whether the
// SST is external.
SequenceNumber global_seqno(0);
if (seqno_pos != props.end()) {
global_seqno = DecodeFixed64(seqno_pos->second.c_str());
}
// SstTableReader open table reader with kMaxSequenceNumber as largest_seqno
// to denote it is unknown.
if (largest_seqno < kMaxSequenceNumber) {
if (global_seqno == 0) {
global_seqno = largest_seqno;
}
if (global_seqno != largest_seqno) {
std::array<char, 200> msg_buf;
snprintf(
msg_buf.data(), msg_buf.max_size(),
"An external sst file with version %u have global seqno property "
"with value %s, while largest seqno in the file is %llu",
version, seqno_pos->second.c_str(),
static_cast<unsigned long long>(largest_seqno));
return Status::Corruption(msg_buf.data());
}
}
*seqno = global_seqno;
if (global_seqno > kMaxSequenceNumber) {
std::array<char, 200> msg_buf;
snprintf(msg_buf.data(), msg_buf.max_size(),
"An external sst file with version %u have global seqno property "
"with value %llu, which is greater than kMaxSequenceNumber",
version, static_cast<unsigned long long>(global_seqno));
return Status::Corruption(msg_buf.data());
}
return Status::OK();
}
} // namespace
Slice BlockBasedTable::GetCacheKey(const char* cache_key_prefix,
size_t cache_key_prefix_size,
const BlockHandle& handle, char* cache_key) {
assert(cache_key != nullptr);
assert(cache_key_prefix_size != 0);
assert(cache_key_prefix_size <= kMaxCacheKeyPrefixSize);
memcpy(cache_key, cache_key_prefix, cache_key_prefix_size);
char* end =
EncodeVarint64(cache_key + cache_key_prefix_size, handle.offset());
return Slice(cache_key, static_cast<size_t>(end - cache_key));
}
Status BlockBasedTable::Open(
const ImmutableCFOptions& ioptions, const EnvOptions& env_options,
const BlockBasedTableOptions& table_options,
const InternalKeyComparator& internal_comparator,
std::unique_ptr<RandomAccessFileReader>&& file, uint64_t file_size,
std::unique_ptr<TableReader>* table_reader,
const SliceTransform* prefix_extractor,
const bool prefetch_index_and_filter_in_cache, const bool skip_filters,
const int level, const bool immortal_table,
const SequenceNumber largest_seqno, TailPrefetchStats* tail_prefetch_stats,
BlockCacheTracer* const block_cache_tracer) {
table_reader->reset();
Status s;
Footer footer;
std::unique_ptr<FilePrefetchBuffer> prefetch_buffer;
// prefetch both index and filters, down to all partitions
const bool prefetch_all = prefetch_index_and_filter_in_cache || level == 0;
const bool preload_all = !table_options.cache_index_and_filter_blocks;
s = PrefetchTail(file.get(), file_size, tail_prefetch_stats, prefetch_all,
preload_all, &prefetch_buffer);
// Read in the following order:
// 1. Footer
// 2. [metaindex block]
// 3. [meta block: properties]
// 4. [meta block: range deletion tombstone]
// 5. [meta block: compression dictionary]
// 6. [meta block: index]
// 7. [meta block: filter]
s = ReadFooterFromFile(file.get(), prefetch_buffer.get(), file_size, &footer,
kBlockBasedTableMagicNumber);
if (!s.ok()) {
return s;
}
if (!BlockBasedTableSupportedVersion(footer.version())) {
return Status::Corruption(
"Unknown Footer version. Maybe this file was created with newer "
"version of RocksDB?");
}
// We've successfully read the footer. We are ready to serve requests.
// Better not mutate rep_ after the creation. eg. internal_prefix_transform
// raw pointer will be used to create HashIndexReader, whose reset may
// access a dangling pointer.
BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
Rep* rep = new BlockBasedTable::Rep(ioptions, env_options, table_options,
internal_comparator, skip_filters, level,
immortal_table);
rep->file = std::move(file);
rep->footer = footer;
rep->hash_index_allow_collision = table_options.hash_index_allow_collision;
// We need to wrap data with internal_prefix_transform to make sure it can
// handle prefix correctly.
rep->internal_prefix_transform.reset(
new InternalKeySliceTransform(prefix_extractor));
SetupCacheKeyPrefix(rep);
std::unique_ptr<BlockBasedTable> new_table(
new BlockBasedTable(rep, block_cache_tracer));
// page cache options
rep->persistent_cache_options =
PersistentCacheOptions(rep->table_options.persistent_cache,
std::string(rep->persistent_cache_key_prefix,
rep->persistent_cache_key_prefix_size),
rep->ioptions.statistics);
// Meta-blocks are not dictionary compressed. Explicitly set the dictionary
// handle to null, otherwise it may be seen as uninitialized during the below
// meta-block reads.
rep->compression_dict_handle = BlockHandle::NullBlockHandle();
// Read metaindex
std::unique_ptr<Block> meta;
std::unique_ptr<InternalIterator> meta_iter;
s = new_table->ReadMetaBlock(prefetch_buffer.get(), &meta, &meta_iter);
if (!s.ok()) {
return s;
}
// Populates table_properties and some fields that depend on it,
// such as index_type.
s = new_table->ReadPropertiesBlock(prefetch_buffer.get(), meta_iter.get(),
largest_seqno);
if (!s.ok()) {
return s;
}
s = new_table->ReadRangeDelBlock(prefetch_buffer.get(), meta_iter.get(),
internal_comparator, &lookup_context);
if (!s.ok()) {
return s;
}
s = new_table->PrefetchIndexAndFilterBlocks(
prefetch_buffer.get(), meta_iter.get(), new_table.get(), prefetch_all,
table_options, level, &lookup_context);
if (s.ok()) {
// Update tail prefetch stats
assert(prefetch_buffer.get() != nullptr);
if (tail_prefetch_stats != nullptr) {
assert(prefetch_buffer->min_offset_read() < file_size);
tail_prefetch_stats->RecordEffectiveSize(
static_cast<size_t>(file_size) - prefetch_buffer->min_offset_read());
}
*table_reader = std::move(new_table);
}
return s;
}
Status BlockBasedTable::PrefetchTail(
RandomAccessFileReader* file, uint64_t file_size,
TailPrefetchStats* tail_prefetch_stats, const bool prefetch_all,
const bool preload_all,
std::unique_ptr<FilePrefetchBuffer>* prefetch_buffer) {
size_t tail_prefetch_size = 0;
if (tail_prefetch_stats != nullptr) {
// Multiple threads may get a 0 (no history) when running in parallel,
// but it will get cleared after the first of them finishes.
tail_prefetch_size = tail_prefetch_stats->GetSuggestedPrefetchSize();
}
if (tail_prefetch_size == 0) {
// Before read footer, readahead backwards to prefetch data. Do more
// readahead if we're going to read index/filter.
// TODO: This may incorrectly select small readahead in case partitioned
// index/filter is enabled and top-level partition pinning is enabled.
// That's because we need to issue readahead before we read the properties,
// at which point we don't yet know the index type.
tail_prefetch_size = prefetch_all || preload_all ? 512 * 1024 : 4 * 1024;
}
size_t prefetch_off;
size_t prefetch_len;
if (file_size < tail_prefetch_size) {
prefetch_off = 0;
prefetch_len = static_cast<size_t>(file_size);
} else {
prefetch_off = static_cast<size_t>(file_size - tail_prefetch_size);
prefetch_len = tail_prefetch_size;
}
TEST_SYNC_POINT_CALLBACK("BlockBasedTable::Open::TailPrefetchLen",
&tail_prefetch_size);
Status s;
// TODO should not have this special logic in the future.
if (!file->use_direct_io()) {
prefetch_buffer->reset(new FilePrefetchBuffer(nullptr, 0, 0, false, true));
s = file->Prefetch(prefetch_off, prefetch_len);
} else {
prefetch_buffer->reset(new FilePrefetchBuffer(nullptr, 0, 0, true, true));
s = (*prefetch_buffer)->Prefetch(file, prefetch_off, prefetch_len);
}
return s;
}
Status VerifyChecksum(const ChecksumType type, const char* buf, size_t len,
uint32_t expected) {
Status s;
uint32_t actual = 0;
switch (type) {
case kNoChecksum:
break;
case kCRC32c:
expected = crc32c::Unmask(expected);
actual = crc32c::Value(buf, len);
break;
case kxxHash:
actual = XXH32(buf, static_cast<int>(len), 0);
break;
case kxxHash64:
actual = static_cast<uint32_t>(XXH64(buf, static_cast<int>(len), 0) &
uint64_t{0xffffffff});
break;
default:
s = Status::Corruption("unknown checksum type");
}
if (s.ok() && actual != expected) {
s = Status::Corruption("properties block checksum mismatched");
}
return s;
}
Status BlockBasedTable::TryReadPropertiesWithGlobalSeqno(
FilePrefetchBuffer* prefetch_buffer, const Slice& handle_value,
TableProperties** table_properties) {
assert(table_properties != nullptr);
// If this is an external SST file ingested with write_global_seqno set to
// true, then we expect the checksum mismatch because checksum was written
// by SstFileWriter, but its global seqno in the properties block may have
// been changed during ingestion. In this case, we read the properties
// block, copy it to a memory buffer, change the global seqno to its
// original value, i.e. 0, and verify the checksum again.
BlockHandle props_block_handle;
CacheAllocationPtr tmp_buf;
Status s = ReadProperties(handle_value, rep_->file.get(), prefetch_buffer,
rep_->footer, rep_->ioptions, table_properties,
false /* verify_checksum */, &props_block_handle,
&tmp_buf, false /* compression_type_missing */,
nullptr /* memory_allocator */);
if (s.ok() && tmp_buf) {
const auto seqno_pos_iter =
(*table_properties)
->properties_offsets.find(
ExternalSstFilePropertyNames::kGlobalSeqno);
size_t block_size = static_cast<size_t>(props_block_handle.size());
if (seqno_pos_iter != (*table_properties)->properties_offsets.end()) {
uint64_t global_seqno_offset = seqno_pos_iter->second;
EncodeFixed64(
tmp_buf.get() + global_seqno_offset - props_block_handle.offset(), 0);
}
uint32_t value = DecodeFixed32(tmp_buf.get() + block_size + 1);
s = rocksdb::VerifyChecksum(rep_->footer.checksum(), tmp_buf.get(),
block_size + 1, value);
}
return s;
}
Status BlockBasedTable::ReadPropertiesBlock(
FilePrefetchBuffer* prefetch_buffer, InternalIterator* meta_iter,
const SequenceNumber largest_seqno) {
bool found_properties_block = true;
Status s;
s = SeekToPropertiesBlock(meta_iter, &found_properties_block);
if (!s.ok()) {
ROCKS_LOG_WARN(rep_->ioptions.info_log,
"Error when seeking to properties block from file: %s",
s.ToString().c_str());
} else if (found_properties_block) {
s = meta_iter->status();
TableProperties* table_properties = nullptr;
if (s.ok()) {
s = ReadProperties(
meta_iter->value(), rep_->file.get(), prefetch_buffer, rep_->footer,
rep_->ioptions, &table_properties, true /* verify_checksum */,
nullptr /* ret_block_handle */, nullptr /* ret_block_contents */,
false /* compression_type_missing */, nullptr /* memory_allocator */);
}
if (s.IsCorruption()) {
s = TryReadPropertiesWithGlobalSeqno(prefetch_buffer, meta_iter->value(),
&table_properties);
}
std::unique_ptr<TableProperties> props_guard;
if (table_properties != nullptr) {
props_guard.reset(table_properties);
}
if (!s.ok()) {
ROCKS_LOG_WARN(rep_->ioptions.info_log,
"Encountered error while reading data from properties "
"block %s",
s.ToString().c_str());
} else {
assert(table_properties != nullptr);
rep_->table_properties.reset(props_guard.release());
rep_->blocks_maybe_compressed =
rep_->table_properties->compression_name !=
CompressionTypeToString(kNoCompression);
rep_->blocks_definitely_zstd_compressed =
(rep_->table_properties->compression_name ==
CompressionTypeToString(kZSTD) ||
rep_->table_properties->compression_name ==
CompressionTypeToString(kZSTDNotFinalCompression));
}
} else {
ROCKS_LOG_ERROR(rep_->ioptions.info_log,
"Cannot find Properties block from file.");
}
#ifndef ROCKSDB_LITE
if (rep_->table_properties) {
ParseSliceTransform(rep_->table_properties->prefix_extractor_name,
&(rep_->table_prefix_extractor));
}
#endif // ROCKSDB_LITE
// Read the table properties, if provided.
if (rep_->table_properties) {
rep_->whole_key_filtering &=
IsFeatureSupported(*(rep_->table_properties),
BlockBasedTablePropertyNames::kWholeKeyFiltering,
rep_->ioptions.info_log);
rep_->prefix_filtering &=
IsFeatureSupported(*(rep_->table_properties),
BlockBasedTablePropertyNames::kPrefixFiltering,
rep_->ioptions.info_log);
rep_->index_key_includes_seq =
rep_->table_properties->index_key_is_user_key == 0;
rep_->index_value_is_full =
rep_->table_properties->index_value_is_delta_encoded == 0;
// Update index_type with the true type.
// If table properties don't contain index type, we assume that the table
// is in very old format and has kBinarySearch index type.
auto& props = rep_->table_properties->user_collected_properties;
auto pos = props.find(BlockBasedTablePropertyNames::kIndexType);
if (pos != props.end()) {
rep_->index_type = static_cast<BlockBasedTableOptions::IndexType>(
DecodeFixed32(pos->second.c_str()));
}
rep_->index_has_first_key =
rep_->index_type == BlockBasedTableOptions::kBinarySearchWithFirstKey;
s = GetGlobalSequenceNumber(*(rep_->table_properties), largest_seqno,
&(rep_->global_seqno));
if (!s.ok()) {
ROCKS_LOG_ERROR(rep_->ioptions.info_log, "%s", s.ToString().c_str());
}
}
return s;
}
Status BlockBasedTable::ReadRangeDelBlock(
FilePrefetchBuffer* prefetch_buffer, InternalIterator* meta_iter,
const InternalKeyComparator& internal_comparator,
BlockCacheLookupContext* lookup_context) {
Status s;
bool found_range_del_block;
BlockHandle range_del_handle;
s = SeekToRangeDelBlock(meta_iter, &found_range_del_block, &range_del_handle);
if (!s.ok()) {
ROCKS_LOG_WARN(
rep_->ioptions.info_log,
"Error when seeking to range delete tombstones block from file: %s",
s.ToString().c_str());
} else if (found_range_del_block && !range_del_handle.IsNull()) {
ReadOptions read_options;
std::unique_ptr<InternalIterator> iter(NewDataBlockIterator<DataBlockIter>(
read_options, range_del_handle,
/*input_iter=*/nullptr, BlockType::kRangeDeletion,
/*get_context=*/nullptr, lookup_context, Status(), prefetch_buffer));
assert(iter != nullptr);
s = iter->status();
if (!s.ok()) {
ROCKS_LOG_WARN(
rep_->ioptions.info_log,
"Encountered error while reading data from range del block %s",
s.ToString().c_str());
} else {
rep_->fragmented_range_dels =
std::make_shared<FragmentedRangeTombstoneList>(std::move(iter),
internal_comparator);
}
}
return s;
}
Status BlockBasedTable::PrefetchIndexAndFilterBlocks(
FilePrefetchBuffer* prefetch_buffer, InternalIterator* meta_iter,
BlockBasedTable* new_table, bool prefetch_all,
const BlockBasedTableOptions& table_options, const int level,
BlockCacheLookupContext* lookup_context) {
Status s;
// Find filter handle and filter type
if (rep_->filter_policy) {
for (auto filter_type :
{Rep::FilterType::kFullFilter, Rep::FilterType::kPartitionedFilter,
Rep::FilterType::kBlockFilter}) {
std::string prefix;
switch (filter_type) {
case Rep::FilterType::kFullFilter:
prefix = kFullFilterBlockPrefix;
break;
case Rep::FilterType::kPartitionedFilter:
prefix = kPartitionedFilterBlockPrefix;
break;
case Rep::FilterType::kBlockFilter:
prefix = kFilterBlockPrefix;
break;
default:
assert(0);
}
std::string filter_block_key = prefix;
filter_block_key.append(rep_->filter_policy->Name());
if (FindMetaBlock(meta_iter, filter_block_key, &rep_->filter_handle)
.ok()) {
rep_->filter_type = filter_type;
break;
}
}
}
// Find compression dictionary handle
bool found_compression_dict = false;
s = SeekToCompressionDictBlock(meta_iter, &found_compression_dict,
&rep_->compression_dict_handle);
if (!s.ok()) {
return s;
}
BlockBasedTableOptions::IndexType index_type = rep_->index_type;
const bool use_cache = table_options.cache_index_and_filter_blocks;
// pin both index and filters, down to all partitions
const bool pin_all =
rep_->table_options.pin_l0_filter_and_index_blocks_in_cache && level == 0;
// prefetch the first level of index
const bool prefetch_index =
prefetch_all ||
(table_options.pin_top_level_index_and_filter &&
index_type == BlockBasedTableOptions::kTwoLevelIndexSearch);
// pin the first level of index
const bool pin_index =
pin_all || (table_options.pin_top_level_index_and_filter &&
index_type == BlockBasedTableOptions::kTwoLevelIndexSearch);
std::unique_ptr<IndexReader> index_reader;
s = new_table->CreateIndexReader(prefetch_buffer, meta_iter, use_cache,
prefetch_index, pin_index, lookup_context,
&index_reader);
if (!s.ok()) {
return s;
}
rep_->index_reader = std::move(index_reader);
// The partitions of partitioned index are always stored in cache. They
// are hence follow the configuration for pin and prefetch regardless of
// the value of cache_index_and_filter_blocks
if (prefetch_all) {
rep_->index_reader->CacheDependencies(pin_all);
}
// prefetch the first level of filter
const bool prefetch_filter =
prefetch_all ||
(table_options.pin_top_level_index_and_filter &&
rep_->filter_type == Rep::FilterType::kPartitionedFilter);
// Partition fitlers cannot be enabled without partition indexes
assert(!prefetch_filter || prefetch_index);
// pin the first level of filter
const bool pin_filter =
pin_all || (table_options.pin_top_level_index_and_filter &&
rep_->filter_type == Rep::FilterType::kPartitionedFilter);
if (rep_->filter_policy) {
auto filter = new_table->CreateFilterBlockReader(
prefetch_buffer, use_cache, prefetch_filter, pin_filter,
lookup_context);
if (filter) {
// Refer to the comment above about paritioned indexes always being cached
if (prefetch_all) {
filter->CacheDependencies(pin_all);
}
rep_->filter = std::move(filter);
}
}
if (!rep_->compression_dict_handle.IsNull()) {
std::unique_ptr<UncompressionDictReader> uncompression_dict_reader;
s = UncompressionDictReader::Create(this, prefetch_buffer, use_cache,
prefetch_all, pin_all, lookup_context,
&uncompression_dict_reader);
if (!s.ok()) {
return s;
}
rep_->uncompression_dict_reader = std::move(uncompression_dict_reader);
}
assert(s.ok());
return s;
}
void BlockBasedTable::SetupForCompaction() {
switch (rep_->ioptions.access_hint_on_compaction_start) {
case Options::NONE:
break;
case Options::NORMAL:
rep_->file->file()->Hint(RandomAccessFile::NORMAL);
break;
case Options::SEQUENTIAL:
rep_->file->file()->Hint(RandomAccessFile::SEQUENTIAL);
break;
case Options::WILLNEED:
rep_->file->file()->Hint(RandomAccessFile::WILLNEED);
break;
default:
assert(false);
}
}
std::shared_ptr<const TableProperties> BlockBasedTable::GetTableProperties()
const {
return rep_->table_properties;
}
size_t BlockBasedTable::ApproximateMemoryUsage() const {
size_t usage = 0;
if (rep_->filter) {
usage += rep_->filter->ApproximateMemoryUsage();
}
if (rep_->index_reader) {
usage += rep_->index_reader->ApproximateMemoryUsage();
}
if (rep_->uncompression_dict_reader) {
usage += rep_->uncompression_dict_reader->ApproximateMemoryUsage();
}
return usage;
}
// Load the meta-block from the file. On success, return the loaded meta block
// and its iterator.
Status BlockBasedTable::ReadMetaBlock(FilePrefetchBuffer* prefetch_buffer,
std::unique_ptr<Block>* meta_block,
std::unique_ptr<InternalIterator>* iter) {
// TODO(sanjay): Skip this if footer.metaindex_handle() size indicates
// it is an empty block.
std::unique_ptr<Block> meta;
Status s = ReadBlockFromFile(
rep_->file.get(), prefetch_buffer, rep_->footer, ReadOptions(),
rep_->footer.metaindex_handle(), &meta, rep_->ioptions,
true /* decompress */, true /*maybe_compressed*/, BlockType::kMetaIndex,
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options,
kDisableGlobalSequenceNumber, 0 /* read_amp_bytes_per_bit */,
GetMemoryAllocator(rep_->table_options), false /* for_compaction */,
rep_->blocks_definitely_zstd_compressed);
if (!s.ok()) {
ROCKS_LOG_ERROR(rep_->ioptions.info_log,
"Encountered error while reading data from properties"
" block %s",
s.ToString().c_str());
return s;
}
*meta_block = std::move(meta);
// meta block uses bytewise comparator.
iter->reset(meta_block->get()->NewDataIterator(BytewiseComparator(),
BytewiseComparator()));
return Status::OK();
}
template <typename TBlocklike>
Status BlockBasedTable::GetDataBlockFromCache(
const Slice& block_cache_key, const Slice& compressed_block_cache_key,
Cache* block_cache, Cache* block_cache_compressed,
const ReadOptions& read_options, CachableEntry<TBlocklike>* block,
const UncompressionDict& uncompression_dict, BlockType block_type,
GetContext* get_context) const {
const size_t read_amp_bytes_per_bit =
block_type == BlockType::kData
? rep_->table_options.read_amp_bytes_per_bit
: 0;
assert(block);
assert(block->IsEmpty());
Status s;
BlockContents* compressed_block = nullptr;
Cache::Handle* block_cache_compressed_handle = nullptr;
// Lookup uncompressed cache first
if (block_cache != nullptr) {
auto cache_handle = GetEntryFromCache(block_cache, block_cache_key,
block_type, get_context);
if (cache_handle != nullptr) {
block->SetCachedValue(
reinterpret_cast<TBlocklike*>(block_cache->Value(cache_handle)),
block_cache, cache_handle);
return s;
}
}
// If not found, search from the compressed block cache.
assert(block->IsEmpty());
if (block_cache_compressed == nullptr) {
return s;
}
assert(!compressed_block_cache_key.empty());
block_cache_compressed_handle =
block_cache_compressed->Lookup(compressed_block_cache_key);
Statistics* statistics = rep_->ioptions.statistics;
// if we found in the compressed cache, then uncompress and insert into
// uncompressed cache
if (block_cache_compressed_handle == nullptr) {
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_MISS);
return s;
}
// found compressed block
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_HIT);
compressed_block = reinterpret_cast<BlockContents*>(
block_cache_compressed->Value(block_cache_compressed_handle));
CompressionType compression_type = compressed_block->get_compression_type();
assert(compression_type != kNoCompression);
// Retrieve the uncompressed contents into a new buffer
BlockContents contents;
UncompressionContext context(compression_type);
UncompressionInfo info(context, uncompression_dict, compression_type);
s = UncompressBlockContents(
info, compressed_block->data.data(), compressed_block->data.size(),
&contents, rep_->table_options.format_version, rep_->ioptions,
GetMemoryAllocator(rep_->table_options));
// Insert uncompressed block into block cache
if (s.ok()) {
std::unique_ptr<TBlocklike> block_holder(
BlocklikeTraits<TBlocklike>::Create(
std::move(contents), rep_->get_global_seqno(block_type),
read_amp_bytes_per_bit, statistics,
rep_->blocks_definitely_zstd_compressed)); // uncompressed block
if (block_cache != nullptr && block_holder->own_bytes() &&
read_options.fill_cache) {
size_t charge = block_holder->ApproximateMemoryUsage();
Cache::Handle* cache_handle = nullptr;
s = block_cache->Insert(block_cache_key, block_holder.get(), charge,
&DeleteCachedEntry<TBlocklike>, &cache_handle);
if (s.ok()) {
assert(cache_handle != nullptr);
block->SetCachedValue(block_holder.release(), block_cache,
cache_handle);
UpdateCacheInsertionMetrics(block_type, get_context, charge);
} else {
RecordTick(statistics, BLOCK_CACHE_ADD_FAILURES);
}
} else {
block->SetOwnedValue(block_holder.release());
}
}
// Release hold on compressed cache entry
block_cache_compressed->Release(block_cache_compressed_handle);
return s;
}
template <typename TBlocklike>
Status BlockBasedTable::PutDataBlockToCache(
const Slice& block_cache_key, const Slice& compressed_block_cache_key,
Cache* block_cache, Cache* block_cache_compressed,
CachableEntry<TBlocklike>* cached_block, BlockContents* raw_block_contents,
CompressionType raw_block_comp_type,
const UncompressionDict& uncompression_dict, SequenceNumber seq_no,
MemoryAllocator* memory_allocator, BlockType block_type,
GetContext* get_context) const {
const ImmutableCFOptions& ioptions = rep_->ioptions;
const uint32_t format_version = rep_->table_options.format_version;
const size_t read_amp_bytes_per_bit =
block_type == BlockType::kData
? rep_->table_options.read_amp_bytes_per_bit
: 0;
const Cache::Priority priority =
rep_->table_options.cache_index_and_filter_blocks_with_high_priority &&
(block_type == BlockType::kFilter ||
block_type == BlockType::kCompressionDictionary ||
block_type == BlockType::kIndex)
? Cache::Priority::HIGH
: Cache::Priority::LOW;
assert(cached_block);
assert(cached_block->IsEmpty());
Status s;
Statistics* statistics = ioptions.statistics;
std::unique_ptr<TBlocklike> block_holder;
if (raw_block_comp_type != kNoCompression) {
// Retrieve the uncompressed contents into a new buffer
BlockContents uncompressed_block_contents;
UncompressionContext context(raw_block_comp_type);
UncompressionInfo info(context, uncompression_dict, raw_block_comp_type);
s = UncompressBlockContents(info, raw_block_contents->data.data(),
raw_block_contents->data.size(),
&uncompressed_block_contents, format_version,
ioptions, memory_allocator);
if (!s.ok()) {
return s;
}
block_holder.reset(BlocklikeTraits<TBlocklike>::Create(
std::move(uncompressed_block_contents), seq_no, read_amp_bytes_per_bit,
statistics, rep_->blocks_definitely_zstd_compressed));
} else {
block_holder.reset(BlocklikeTraits<TBlocklike>::Create(
std::move(*raw_block_contents), seq_no, read_amp_bytes_per_bit,
statistics, rep_->blocks_definitely_zstd_compressed));
}
// Insert compressed block into compressed block cache.
// Release the hold on the compressed cache entry immediately.
if (block_cache_compressed != nullptr &&
raw_block_comp_type != kNoCompression && raw_block_contents != nullptr &&
raw_block_contents->own_bytes()) {
#ifndef NDEBUG
assert(raw_block_contents->is_raw_block);
#endif // NDEBUG
// We cannot directly put raw_block_contents because this could point to
// an object in the stack.
BlockContents* block_cont_for_comp_cache =
new BlockContents(std::move(*raw_block_contents));
s = block_cache_compressed->Insert(
compressed_block_cache_key, block_cont_for_comp_cache,
block_cont_for_comp_cache->ApproximateMemoryUsage(),
&DeleteCachedEntry<BlockContents>);
if (s.ok()) {
// Avoid the following code to delete this cached block.
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_ADD);
} else {
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_ADD_FAILURES);
delete block_cont_for_comp_cache;
}
}
// insert into uncompressed block cache
if (block_cache != nullptr && block_holder->own_bytes()) {
size_t charge = block_holder->ApproximateMemoryUsage();
Cache::Handle* cache_handle = nullptr;
s = block_cache->Insert(block_cache_key, block_holder.get(), charge,
&DeleteCachedEntry<TBlocklike>, &cache_handle,
priority);
if (s.ok()) {
assert(cache_handle != nullptr);
cached_block->SetCachedValue(block_holder.release(), block_cache,
cache_handle);
UpdateCacheInsertionMetrics(block_type, get_context, charge);
} else {
RecordTick(statistics, BLOCK_CACHE_ADD_FAILURES);
}
} else {
cached_block->SetOwnedValue(block_holder.release());
}
return s;
}
std::unique_ptr<FilterBlockReader> BlockBasedTable::CreateFilterBlockReader(
FilePrefetchBuffer* prefetch_buffer, bool use_cache, bool prefetch,
bool pin, BlockCacheLookupContext* lookup_context) {
auto& rep = rep_;
auto filter_type = rep->filter_type;
if (filter_type == Rep::FilterType::kNoFilter) {
return std::unique_ptr<FilterBlockReader>();
}
assert(rep->filter_policy);
switch (filter_type) {
case Rep::FilterType::kPartitionedFilter:
return PartitionedFilterBlockReader::Create(
this, prefetch_buffer, use_cache, prefetch, pin, lookup_context);
case Rep::FilterType::kBlockFilter:
return BlockBasedFilterBlockReader::Create(
this, prefetch_buffer, use_cache, prefetch, pin, lookup_context);
case Rep::FilterType::kFullFilter:
return FullFilterBlockReader::Create(this, prefetch_buffer, use_cache,
prefetch, pin, lookup_context);
default:
// filter_type is either kNoFilter (exited the function at the first if),
// or it must be covered in this switch block
assert(false);
return std::unique_ptr<FilterBlockReader>();
}
}
// disable_prefix_seek should be set to true when prefix_extractor found in SST
// differs from the one in mutable_cf_options and index type is HashBasedIndex
InternalIteratorBase<IndexValue>* BlockBasedTable::NewIndexIterator(
const ReadOptions& read_options, bool disable_prefix_seek,
IndexBlockIter* input_iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) const {
assert(rep_ != nullptr);
assert(rep_->index_reader != nullptr);
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
return rep_->index_reader->NewIterator(read_options, disable_prefix_seek,
input_iter, get_context,
lookup_context);
}
// Convert an index iterator value (i.e., an encoded BlockHandle)
// into an iterator over the contents of the corresponding block.
// If input_iter is null, new a iterator
// If input_iter is not null, update this iter and return it
template <typename TBlockIter>
TBlockIter* BlockBasedTable::NewDataBlockIterator(
const ReadOptions& ro, const BlockHandle& handle, TBlockIter* input_iter,
BlockType block_type, GetContext* get_context,
BlockCacheLookupContext* lookup_context, Status s,
FilePrefetchBuffer* prefetch_buffer, bool for_compaction) const {
PERF_TIMER_GUARD(new_table_block_iter_nanos);
TBlockIter* iter = input_iter != nullptr ? input_iter : new TBlockIter;
if (!s.ok()) {
iter->Invalidate(s);
return iter;
}
CachableEntry<UncompressionDict> uncompression_dict;
if (rep_->uncompression_dict_reader) {
const bool no_io = (ro.read_tier == kBlockCacheTier);
s = rep_->uncompression_dict_reader->GetOrReadUncompressionDictionary(
prefetch_buffer, no_io, get_context, lookup_context,
&uncompression_dict);
if (!s.ok()) {
iter->Invalidate(s);
return iter;
}
}
const UncompressionDict& dict = uncompression_dict.GetValue()
? *uncompression_dict.GetValue()
: UncompressionDict::GetEmptyDict();
CachableEntry<Block> block;
s = RetrieveBlock(prefetch_buffer, ro, handle, dict, &block, block_type,
get_context, lookup_context, for_compaction,
/* use_cache */ true);
if (!s.ok()) {
assert(block.IsEmpty());
iter->Invalidate(s);
return iter;
}
assert(block.GetValue() != nullptr);
// Block contents are pinned and it is still pinned after the iterator
// is destroyed as long as cleanup functions are moved to another object,
// when:
// 1. block cache handle is set to be released in cleanup function, or
// 2. it's pointing to immortal source. If own_bytes is true then we are
// not reading data from the original source, whether immortal or not.
// Otherwise, the block is pinned iff the source is immortal.
const bool block_contents_pinned =
block.IsCached() ||
(!block.GetValue()->own_bytes() && rep_->immortal_table);
iter = InitBlockIterator<TBlockIter>(rep_, block.GetValue(), iter,
block_contents_pinned);
if (!block.IsCached()) {
if (!ro.fill_cache && rep_->cache_key_prefix_size != 0) {
// insert a dummy record to block cache to track the memory usage
Cache* const block_cache = rep_->table_options.block_cache.get();
Cache::Handle* cache_handle = nullptr;
// There are two other types of cache keys: 1) SST cache key added in
// `MaybeReadBlockAndLoadToCache` 2) dummy cache key added in
// `write_buffer_manager`. Use longer prefix (41 bytes) to differentiate
// from SST cache key(31 bytes), and use non-zero prefix to
// differentiate from `write_buffer_manager`
const size_t kExtraCacheKeyPrefix = kMaxVarint64Length * 4 + 1;
char cache_key[kExtraCacheKeyPrefix + kMaxVarint64Length];
// Prefix: use rep_->cache_key_prefix padded by 0s
memset(cache_key, 0, kExtraCacheKeyPrefix + kMaxVarint64Length);
assert(rep_->cache_key_prefix_size != 0);
assert(rep_->cache_key_prefix_size <= kExtraCacheKeyPrefix);
memcpy(cache_key, rep_->cache_key_prefix, rep_->cache_key_prefix_size);
char* end = EncodeVarint64(cache_key + kExtraCacheKeyPrefix,
next_cache_key_id_++);
assert(end - cache_key <=
static_cast<int>(kExtraCacheKeyPrefix + kMaxVarint64Length));
const Slice unique_key(cache_key, static_cast<size_t>(end - cache_key));
s = block_cache->Insert(unique_key, nullptr,
block.GetValue()->ApproximateMemoryUsage(),
nullptr, &cache_handle);
if (s.ok()) {
assert(cache_handle != nullptr);
iter->RegisterCleanup(&ForceReleaseCachedEntry, block_cache,
cache_handle);
}
}
} else {
iter->SetCacheHandle(block.GetCacheHandle());
}
block.TransferTo(iter);
return iter;
}
template <>
DataBlockIter* BlockBasedTable::InitBlockIterator<DataBlockIter>(
const Rep* rep, Block* block, DataBlockIter* input_iter,
bool block_contents_pinned) {
return block->NewDataIterator(
&rep->internal_comparator, rep->internal_comparator.user_comparator(),
input_iter, rep->ioptions.statistics, block_contents_pinned);
}
template <>
IndexBlockIter* BlockBasedTable::InitBlockIterator<IndexBlockIter>(
const Rep* rep, Block* block, IndexBlockIter* input_iter,
bool block_contents_pinned) {
return block->NewIndexIterator(
&rep->internal_comparator, rep->internal_comparator.user_comparator(),
input_iter, rep->ioptions.statistics, /* total_order_seek */ true,
rep->index_has_first_key, rep->index_key_includes_seq,
rep->index_value_is_full, block_contents_pinned);
}
// Convert an uncompressed data block (i.e CachableEntry<Block>)
// into an iterator over the contents of the corresponding block.
// If input_iter is null, new a iterator
// If input_iter is not null, update this iter and return it
template <typename TBlockIter>
TBlockIter* BlockBasedTable::NewDataBlockIterator(
const ReadOptions& ro, CachableEntry<Block>& block, TBlockIter* input_iter,
Status s) const {
PERF_TIMER_GUARD(new_table_block_iter_nanos);
TBlockIter* iter = input_iter != nullptr ? input_iter : new TBlockIter;
if (!s.ok()) {
iter->Invalidate(s);
return iter;
}
assert(block.GetValue() != nullptr);
// Block contents are pinned and it is still pinned after the iterator
// is destroyed as long as cleanup functions are moved to another object,
// when:
// 1. block cache handle is set to be released in cleanup function, or
// 2. it's pointing to immortal source. If own_bytes is true then we are
// not reading data from the original source, whether immortal or not.
// Otherwise, the block is pinned iff the source is immortal.
const bool block_contents_pinned =
block.IsCached() ||
(!block.GetValue()->own_bytes() && rep_->immortal_table);
iter = InitBlockIterator<TBlockIter>(rep_, block.GetValue(), iter,
block_contents_pinned);
if (!block.IsCached()) {
if (!ro.fill_cache && rep_->cache_key_prefix_size != 0) {
// insert a dummy record to block cache to track the memory usage
Cache* const block_cache = rep_->table_options.block_cache.get();
Cache::Handle* cache_handle = nullptr;
// There are two other types of cache keys: 1) SST cache key added in
// `MaybeReadBlockAndLoadToCache` 2) dummy cache key added in
// `write_buffer_manager`. Use longer prefix (41 bytes) to differentiate
// from SST cache key(31 bytes), and use non-zero prefix to
// differentiate from `write_buffer_manager`
const size_t kExtraCacheKeyPrefix = kMaxVarint64Length * 4 + 1;
char cache_key[kExtraCacheKeyPrefix + kMaxVarint64Length];
// Prefix: use rep_->cache_key_prefix padded by 0s
memset(cache_key, 0, kExtraCacheKeyPrefix + kMaxVarint64Length);
assert(rep_->cache_key_prefix_size != 0);
assert(rep_->cache_key_prefix_size <= kExtraCacheKeyPrefix);
memcpy(cache_key, rep_->cache_key_prefix, rep_->cache_key_prefix_size);
char* end = EncodeVarint64(cache_key + kExtraCacheKeyPrefix,
next_cache_key_id_++);
assert(end - cache_key <=
static_cast<int>(kExtraCacheKeyPrefix + kMaxVarint64Length));
const Slice unique_key(cache_key, static_cast<size_t>(end - cache_key));
s = block_cache->Insert(unique_key, nullptr,
block.GetValue()->ApproximateMemoryUsage(),
nullptr, &cache_handle);
if (s.ok()) {
assert(cache_handle != nullptr);
iter->RegisterCleanup(&ForceReleaseCachedEntry, block_cache,
cache_handle);
}
}
} else {
iter->SetCacheHandle(block.GetCacheHandle());
}
block.TransferTo(iter);
return iter;
}
// If contents is nullptr, this function looks up the block caches for the
// data block referenced by handle, and read the block from disk if necessary.
// If contents is non-null, it skips the cache lookup and disk read, since
// the caller has already read it. In both cases, if ro.fill_cache is true,
// it inserts the block into the block cache.
template <typename TBlocklike>
Status BlockBasedTable::MaybeReadBlockAndLoadToCache(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<TBlocklike>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
BlockContents* contents) const {
assert(block_entry != nullptr);
const bool no_io = (ro.read_tier == kBlockCacheTier);
Cache* block_cache = rep_->table_options.block_cache.get();
// No point to cache compressed blocks if it never goes away
Cache* block_cache_compressed =
rep_->immortal_table ? nullptr
: rep_->table_options.block_cache_compressed.get();
// First, try to get the block from the cache
//
// If either block cache is enabled, we'll try to read from it.
Status s;
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
char compressed_cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
Slice key /* key to the block cache */;
Slice ckey /* key to the compressed block cache */;
bool is_cache_hit = false;
if (block_cache != nullptr || block_cache_compressed != nullptr) {
// create key for block cache
if (block_cache != nullptr) {
key = GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
handle, cache_key);
}
if (block_cache_compressed != nullptr) {
ckey = GetCacheKey(rep_->compressed_cache_key_prefix,
rep_->compressed_cache_key_prefix_size, handle,
compressed_cache_key);
}
if (!contents) {
s = GetDataBlockFromCache(key, ckey, block_cache, block_cache_compressed,
ro, block_entry, uncompression_dict, block_type,
get_context);
if (block_entry->GetValue()) {
// TODO(haoyu): Differentiate cache hit on uncompressed block cache and
// compressed block cache.
is_cache_hit = true;
}
}
// Can't find the block from the cache. If I/O is allowed, read from the
// file.
if (block_entry->GetValue() == nullptr && !no_io && ro.fill_cache) {
Statistics* statistics = rep_->ioptions.statistics;
const bool maybe_compressed =
block_type != BlockType::kFilter &&
block_type != BlockType::kCompressionDictionary &&
rep_->blocks_maybe_compressed;
const bool do_uncompress = maybe_compressed && !block_cache_compressed;
CompressionType raw_block_comp_type;
BlockContents raw_block_contents;
if (!contents) {
StopWatch sw(rep_->ioptions.env, statistics, READ_BLOCK_GET_MICROS);
BlockFetcher block_fetcher(
rep_->file.get(), prefetch_buffer, rep_->footer, ro, handle,
&raw_block_contents, rep_->ioptions, do_uncompress,
maybe_compressed, block_type, uncompression_dict,
rep_->persistent_cache_options,
GetMemoryAllocator(rep_->table_options),
GetMemoryAllocatorForCompressedBlock(rep_->table_options));
s = block_fetcher.ReadBlockContents();
raw_block_comp_type = block_fetcher.get_compression_type();
contents = &raw_block_contents;
} else {
raw_block_comp_type = contents->get_compression_type();
}
if (s.ok()) {
SequenceNumber seq_no = rep_->get_global_seqno(block_type);
// If filling cache is allowed and a cache is configured, try to put the
// block to the cache.
s = PutDataBlockToCache(key, ckey, block_cache, block_cache_compressed,
block_entry, contents,
raw_block_comp_type, uncompression_dict, seq_no,
GetMemoryAllocator(rep_->table_options),
block_type, get_context);
}
}
}
// Fill lookup_context.
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled() &&
lookup_context) {
size_t usage = 0;
uint64_t nkeys = 0;
if (block_entry->GetValue()) {
// Approximate the number of keys in the block using restarts.
nkeys =
rep_->table_options.block_restart_interval *
BlocklikeTraits<TBlocklike>::GetNumRestarts(*block_entry->GetValue());
usage = block_entry->GetValue()->ApproximateMemoryUsage();
}
TraceType trace_block_type = TraceType::kTraceMax;
switch (block_type) {
case BlockType::kData:
trace_block_type = TraceType::kBlockTraceDataBlock;
break;
case BlockType::kFilter:
trace_block_type = TraceType::kBlockTraceFilterBlock;
break;
case BlockType::kCompressionDictionary:
trace_block_type = TraceType::kBlockTraceUncompressionDictBlock;
break;
case BlockType::kRangeDeletion:
trace_block_type = TraceType::kBlockTraceRangeDeletionBlock;
break;
case BlockType::kIndex:
trace_block_type = TraceType::kBlockTraceIndexBlock;
break;
default:
// This cannot happen.
assert(false);
break;
}
bool no_insert = no_io || !ro.fill_cache;
if (BlockCacheTraceHelper::IsGetOrMultiGetOnDataBlock(
trace_block_type, lookup_context->caller)) {
// Defer logging the access to Get() and MultiGet() to trace additional
// information, e.g., referenced_key_exist_in_block.
// Make a copy of the block key here since it will be logged later.
lookup_context->FillLookupContext(
is_cache_hit, no_insert, trace_block_type,
/*block_size=*/usage, /*block_key=*/key.ToString(), nkeys);
} else {
// Avoid making copy of block_key and cf_name when constructing the access
// record.
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", trace_block_type,
/*block_size=*/usage, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_context->caller, is_cache_hit,
no_insert, lookup_context->get_id,
lookup_context->get_from_user_specified_snapshot,
/*referenced_key=*/"");
block_cache_tracer_->WriteBlockAccess(access_record, key,
rep_->cf_name_for_tracing(),
lookup_context->referenced_key);
}
}
assert(s.ok() || block_entry->GetValue() == nullptr);
return s;
}
// This function reads multiple data blocks from disk using Env::MultiRead()
// and optionally inserts them into the block cache. It uses the scratch
// buffer provided by the caller, which is contiguous. If scratch is a nullptr
// it allocates a separate buffer for each block. Typically, if the blocks
// need to be uncompressed and there is no compressed block cache, callers
// can allocate a temporary scratch buffer in order to minimize memory
// allocations.
// If options.fill_cache is true, it inserts the blocks into cache. If its
// false and scratch is non-null and the blocks are uncompressed, it copies
// the buffers to heap. In any case, the CachableEntry<Block> returned will
// own the data bytes.
// batch - A MultiGetRange with only those keys with unique data blocks not
// found in cache
// handles - A vector of block handles. Some of them me be NULL handles
// scratch - An optional contiguous buffer to read compressed blocks into
void BlockBasedTable::RetrieveMultipleBlocks(
const ReadOptions& options, const MultiGetRange* batch,
const autovector<BlockHandle, MultiGetContext::MAX_BATCH_SIZE>* handles,
autovector<Status, MultiGetContext::MAX_BATCH_SIZE>* statuses,
autovector<CachableEntry<Block>, MultiGetContext::MAX_BATCH_SIZE>* results,
char* scratch, const UncompressionDict& uncompression_dict) const {
RandomAccessFileReader* file = rep_->file.get();
const Footer& footer = rep_->footer;
const ImmutableCFOptions& ioptions = rep_->ioptions;
SequenceNumber global_seqno = rep_->get_global_seqno(BlockType::kData);
size_t read_amp_bytes_per_bit = rep_->table_options.read_amp_bytes_per_bit;
MemoryAllocator* memory_allocator = GetMemoryAllocator(rep_->table_options);
if (file->use_direct_io() || ioptions.allow_mmap_reads) {
size_t idx_in_batch = 0;
for (auto mget_iter = batch->begin(); mget_iter != batch->end();
++mget_iter, ++idx_in_batch) {
BlockCacheLookupContext lookup_data_block_context(
TableReaderCaller::kUserMultiGet);
const BlockHandle& handle = (*handles)[idx_in_batch];
if (handle.IsNull()) {
continue;
}
(*statuses)[idx_in_batch] =
RetrieveBlock(nullptr, options, handle, uncompression_dict,
&(*results)[idx_in_batch], BlockType::kData,
mget_iter->get_context, &lookup_data_block_context,
/* for_compaction */ false, /* use_cache */ true);
}
return;
}
autovector<ReadRequest, MultiGetContext::MAX_BATCH_SIZE> read_reqs;
size_t buf_offset = 0;
size_t idx_in_batch = 0;
for (auto mget_iter = batch->begin(); mget_iter != batch->end();
++mget_iter, ++idx_in_batch) {
const BlockHandle& handle = (*handles)[idx_in_batch];
if (handle.IsNull()) {
continue;
}
ReadRequest req;
req.len = handle.size() + kBlockTrailerSize;
if (scratch == nullptr) {
req.scratch = new char[req.len];
} else {
req.scratch = scratch + buf_offset;
buf_offset += req.len;
}
req.offset = handle.offset();
req.status = Status::OK();
read_reqs.emplace_back(req);
}
file->MultiRead(&read_reqs[0], read_reqs.size());
size_t read_req_idx = 0;
idx_in_batch = 0;
for (auto mget_iter = batch->begin(); mget_iter != batch->end();
++mget_iter, ++idx_in_batch) {
const BlockHandle& handle = (*handles)[idx_in_batch];
if (handle.IsNull()) {
continue;
}
ReadRequest& req = read_reqs[read_req_idx++];
Status s = req.status;
if (s.ok()) {
if (req.result.size() != handle.size() + kBlockTrailerSize) {
s = Status::Corruption("truncated block read from " +
rep_->file->file_name() + " offset " +
ToString(handle.offset()) + ", expected " +
ToString(handle.size() + kBlockTrailerSize) +
" bytes, got " + ToString(req.result.size()));
}
}
BlockContents raw_block_contents;
if (s.ok()) {
if (scratch == nullptr) {
// We allocated a buffer for this block. Give ownership of it to
// BlockContents so it can free the memory
assert(req.result.data() == req.scratch);
std::unique_ptr<char[]> raw_block(req.scratch);
raw_block_contents = BlockContents(std::move(raw_block),
handle.size());
} else {
// We used the scratch buffer, so no need to free anything
raw_block_contents = BlockContents(Slice(req.scratch,
handle.size()));
}
#ifndef NDEBUG
raw_block_contents.is_raw_block = true;
#endif
if (options.verify_checksums) {
PERF_TIMER_GUARD(block_checksum_time);
const char* data = req.result.data();
uint32_t expected = DecodeFixed32(data + handle.size() + 1);
s = rocksdb::VerifyChecksum(footer.checksum(), req.result.data(),
handle.size() + 1, expected);
}
}
if (s.ok()) {
if (options.fill_cache) {
BlockCacheLookupContext lookup_data_block_context(
TableReaderCaller::kUserMultiGet);
CachableEntry<Block>* block_entry = &(*results)[idx_in_batch];
// MaybeReadBlockAndLoadToCache will insert into the block caches if
// necessary. Since we're passing the raw block contents, it will
// avoid looking up the block cache
s = MaybeReadBlockAndLoadToCache(nullptr, options, handle,
uncompression_dict, block_entry, BlockType::kData,
mget_iter->get_context, &lookup_data_block_context,
&raw_block_contents);
} else {
CompressionType compression_type =
raw_block_contents.get_compression_type();
BlockContents contents;
if (compression_type != kNoCompression) {
UncompressionContext context(compression_type);
UncompressionInfo info(context, uncompression_dict, compression_type);
s = UncompressBlockContents(info, req.result.data(), handle.size(),
&contents, footer.version(), rep_->ioptions,
memory_allocator);
} else {
if (scratch != nullptr) {
// If we used the scratch buffer, then the contents need to be
// copied to heap
Slice raw = Slice(req.result.data(), handle.size());
contents = BlockContents(CopyBufferToHeap(
GetMemoryAllocator(rep_->table_options), raw),
handle.size());
} else {
contents = std::move(raw_block_contents);
}
}
if (s.ok()) {
(*results)[idx_in_batch].SetOwnedValue(new Block(std::move(contents),
global_seqno, read_amp_bytes_per_bit, ioptions.statistics));
}
}
}
(*statuses)[idx_in_batch] = s;
}
}
template <typename TBlocklike>
Status BlockBasedTable::RetrieveBlock(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<TBlocklike>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
bool for_compaction, bool use_cache) const {
assert(block_entry);
assert(block_entry->IsEmpty());
Status s;
if (use_cache) {
s = MaybeReadBlockAndLoadToCache(prefetch_buffer, ro, handle,
uncompression_dict, block_entry,
block_type, get_context, lookup_context,
/*contents=*/nullptr);
if (!s.ok()) {
return s;
}
if (block_entry->GetValue() != nullptr) {
assert(s.ok());
return s;
}
}
assert(block_entry->IsEmpty());
const bool no_io = ro.read_tier == kBlockCacheTier;
if (no_io) {
return Status::Incomplete("no blocking io");
}
const bool maybe_compressed =
block_type != BlockType::kFilter &&
block_type != BlockType::kCompressionDictionary &&
rep_->blocks_maybe_compressed;
const bool do_uncompress = maybe_compressed;
std::unique_ptr<TBlocklike> block;
{
StopWatch sw(rep_->ioptions.env, rep_->ioptions.statistics,
READ_BLOCK_GET_MICROS);
s = ReadBlockFromFile(
rep_->file.get(), prefetch_buffer, rep_->footer, ro, handle, &block,
rep_->ioptions, do_uncompress, maybe_compressed, block_type,
uncompression_dict, rep_->persistent_cache_options,
rep_->get_global_seqno(block_type),
block_type == BlockType::kData
? rep_->table_options.read_amp_bytes_per_bit
: 0,
GetMemoryAllocator(rep_->table_options), for_compaction,
rep_->blocks_definitely_zstd_compressed);
}
if (!s.ok()) {
return s;
}
block_entry->SetOwnedValue(block.release());
assert(s.ok());
return s;
}
// Explicitly instantiate templates for both "blocklike" types we use.
// This makes it possible to keep the template definitions in the .cc file.
template Status BlockBasedTable::RetrieveBlock<BlockContents>(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<BlockContents>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
bool for_compaction, bool use_cache) const;
template Status BlockBasedTable::RetrieveBlock<Block>(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<Block>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
bool for_compaction, bool use_cache) const;
template Status BlockBasedTable::RetrieveBlock<UncompressionDict>(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<UncompressionDict>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
bool for_compaction, bool use_cache) const;
BlockBasedTable::PartitionedIndexIteratorState::PartitionedIndexIteratorState(
const BlockBasedTable* table,
std::unordered_map<uint64_t, CachableEntry<Block>>* block_map)
: table_(table), block_map_(block_map) {}
InternalIteratorBase<IndexValue>*
BlockBasedTable::PartitionedIndexIteratorState::NewSecondaryIterator(
const BlockHandle& handle) {
// Return a block iterator on the index partition
auto block = block_map_->find(handle.offset());
// This is a possible scenario since block cache might not have had space
// for the partition
if (block != block_map_->end()) {
const Rep* rep = table_->get_rep();
assert(rep);
Statistics* kNullStats = nullptr;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
return block->second.GetValue()->NewIndexIterator(
&rep->internal_comparator, rep->internal_comparator.user_comparator(),
nullptr, kNullStats, true, rep->index_has_first_key,
rep->index_key_includes_seq, rep->index_value_is_full);
}
// Create an empty iterator
return new IndexBlockIter();
}
// This will be broken if the user specifies an unusual implementation
// of Options.comparator, or if the user specifies an unusual
// definition of prefixes in BlockBasedTableOptions.filter_policy.
// In particular, we require the following three properties:
//
// 1) key.starts_with(prefix(key))
// 2) Compare(prefix(key), key) <= 0.
// 3) If Compare(key1, key2) <= 0, then Compare(prefix(key1), prefix(key2)) <= 0
//
// Otherwise, this method guarantees no I/O will be incurred.
//
// REQUIRES: this method shouldn't be called while the DB lock is held.
bool BlockBasedTable::PrefixMayMatch(
const Slice& internal_key, const ReadOptions& read_options,
const SliceTransform* options_prefix_extractor,
const bool need_upper_bound_check,
BlockCacheLookupContext* lookup_context) const {
if (!rep_->filter_policy) {
return true;
}
const SliceTransform* prefix_extractor;
if (rep_->table_prefix_extractor == nullptr) {
if (need_upper_bound_check) {
return true;
}
prefix_extractor = options_prefix_extractor;
} else {
prefix_extractor = rep_->table_prefix_extractor.get();
}
auto user_key = ExtractUserKey(internal_key);
if (!prefix_extractor->InDomain(user_key)) {
return true;
}
bool may_match = true;
Status s;
// First, try check with full filter
FilterBlockReader* const filter = rep_->filter.get();
bool filter_checked = true;
if (filter != nullptr) {
if (!filter->IsBlockBased()) {
const Slice* const const_ikey_ptr = &internal_key;
may_match = filter->RangeMayExist(
read_options.iterate_upper_bound, user_key, prefix_extractor,
rep_->internal_comparator.user_comparator(), const_ikey_ptr,
&filter_checked, need_upper_bound_check, lookup_context);
} else {
// if prefix_extractor changed for block based filter, skip filter
if (need_upper_bound_check) {
return true;
}
auto prefix = prefix_extractor->Transform(user_key);
InternalKey internal_key_prefix(prefix, kMaxSequenceNumber, kTypeValue);
auto internal_prefix = internal_key_prefix.Encode();
// To prevent any io operation in this method, we set `read_tier` to make
// sure we always read index or filter only when they have already been
// loaded to memory.
ReadOptions no_io_read_options;
no_io_read_options.read_tier = kBlockCacheTier;
// Then, try find it within each block
// we already know prefix_extractor and prefix_extractor_name must match
// because `CheckPrefixMayMatch` first checks `check_filter_ == true`
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter(NewIndexIterator(
no_io_read_options,
/*need_upper_bound_check=*/false, /*input_iter=*/nullptr,
/*get_context=*/nullptr, lookup_context));
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 ((rep_->index_key_includes_seq ? ExtractUserKey(iiter->key())
: 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->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.
BlockHandle handle = iiter->value().handle;
may_match = filter->PrefixMayMatch(
prefix, prefix_extractor, handle.offset(), /*no_io=*/false,
/*const_key_ptr=*/nullptr, /*get_context=*/nullptr, lookup_context);
}
}
}
if (filter_checked) {
Statistics* statistics = rep_->ioptions.statistics;
RecordTick(statistics, BLOOM_FILTER_PREFIX_CHECKED);
if (!may_match) {
RecordTick(statistics, BLOOM_FILTER_PREFIX_USEFUL);
}
}
return may_match;
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::Seek(const Slice& target) {
SeekImpl(&target);
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekToFirst() {
SeekImpl(nullptr);
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekImpl(
const Slice* target) {
is_out_of_bound_ = false;
is_at_first_key_from_index_ = false;
if (target && !CheckPrefixMayMatch(*target)) {
ResetDataIter();
return;
}
bool need_seek_index = true;
if (block_iter_points_to_real_block_ && block_iter_.Valid()) {
// Reseek.
prev_block_offset_ = index_iter_->value().handle.offset();
if (target) {
// We can avoid an index seek if:
// 1. The new seek key is larger than the current key
// 2. The new seek key is within the upper bound of the block
// Since we don't necessarily know the internal key for either
// the current key or the upper bound, we check user keys and
// exclude the equality case. Considering internal keys can
// improve for the boundary cases, but it would complicate the
// code.
if (user_comparator_.Compare(ExtractUserKey(*target),
block_iter_.user_key()) > 0 &&
user_comparator_.Compare(ExtractUserKey(*target),
index_iter_->user_key()) < 0) {
need_seek_index = false;
}
}
}
if (need_seek_index) {
if (target) {
index_iter_->Seek(*target);
} else {
index_iter_->SeekToFirst();
}
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
}
IndexValue v = index_iter_->value();
const bool same_block = block_iter_points_to_real_block_ &&
v.handle.offset() == prev_block_offset_;
// TODO(kolmike): Remove the != kBlockCacheTier condition.
if (!v.first_internal_key.empty() && !same_block &&
(!target || icomp_.Compare(*target, v.first_internal_key) <= 0) &&
read_options_.read_tier != kBlockCacheTier) {
// Index contains the first key of the block, and it's >= target.
// We can defer reading the block.
is_at_first_key_from_index_ = true;
ResetDataIter();
} else {
// Need to use the data block.
if (!same_block) {
InitDataBlock();
}
if (target) {
block_iter_.Seek(*target);
} else {
block_iter_.SeekToFirst();
}
FindKeyForward();
}
CheckDataBlockWithinUpperBound();
CheckOutOfBound();
if (target) {
assert(!Valid() || ((block_type_ == BlockType::kIndex &&
!table_->get_rep()->index_key_includes_seq)
? (user_comparator_.Compare(ExtractUserKey(*target),
key()) <= 0)
: (icomp_.Compare(*target, key()) <= 0)));
}
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekForPrev(
const Slice& target) {
is_out_of_bound_ = false;
is_at_first_key_from_index_ = false;
if (!CheckPrefixMayMatch(target)) {
ResetDataIter();
return;
}
SavePrevIndexValue();
// Call Seek() rather than SeekForPrev() in the index block, because the
// target data block will likely to contain the position for `target`, the
// same as Seek(), rather than than before.
// For example, if we have three data blocks, each containing two keys:
// [2, 4] [6, 8] [10, 12]
// (the keys in the index block would be [4, 8, 12])
// and the user calls SeekForPrev(7), we need to go to the second block,
// just like if they call Seek(7).
// The only case where the block is difference is when they seek to a position
// in the boundary. For example, if they SeekForPrev(5), we should go to the
// first block, rather than the second. However, we don't have the information
// to distinguish the two unless we read the second block. In this case, we'll
// end up with reading two blocks.
index_iter_->Seek(target);
if (!index_iter_->Valid()) {
if (!index_iter_->status().ok()) {
ResetDataIter();
return;
}
index_iter_->SeekToLast();
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
}
InitDataBlock();
block_iter_.SeekForPrev(target);
FindKeyBackward();
CheckDataBlockWithinUpperBound();
assert(!block_iter_.Valid() ||
icomp_.Compare(target, block_iter_.key()) >= 0);
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekToLast() {
is_out_of_bound_ = false;
is_at_first_key_from_index_ = false;
SavePrevIndexValue();
index_iter_->SeekToLast();
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
InitDataBlock();
block_iter_.SeekToLast();
FindKeyBackward();
CheckDataBlockWithinUpperBound();
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::Next() {
if (is_at_first_key_from_index_ && !MaterializeCurrentBlock()) {
return;
}
assert(block_iter_points_to_real_block_);
block_iter_.Next();
FindKeyForward();
CheckOutOfBound();
}
template <class TBlockIter, typename TValue>
bool BlockBasedTableIterator<TBlockIter, TValue>::NextAndGetResult(
IterateResult* result) {
Next();
bool is_valid = Valid();
if (is_valid) {
result->key = key();
result->may_be_out_of_upper_bound = MayBeOutOfUpperBound();
}
return is_valid;
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::Prev() {
if (is_at_first_key_from_index_) {
is_at_first_key_from_index_ = false;
index_iter_->Prev();
if (!index_iter_->Valid()) {
return;
}
InitDataBlock();
block_iter_.SeekToLast();
} else {
assert(block_iter_points_to_real_block_);
block_iter_.Prev();
}
FindKeyBackward();
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::InitDataBlock() {
BlockHandle data_block_handle = index_iter_->value().handle;
if (!block_iter_points_to_real_block_ ||
data_block_handle.offset() != prev_block_offset_ ||
// if previous attempt of reading the block missed cache, try again
block_iter_.status().IsIncomplete()) {
if (block_iter_points_to_real_block_) {
ResetDataIter();
}
auto* rep = table_->get_rep();
// Prefetch additional data for range scans (iterators). Enabled only for
// user reads.
// Implicit auto readahead:
// Enabled after 2 sequential IOs when ReadOptions.readahead_size == 0.
// Explicit user requested readahead:
// Enabled from the very first IO when ReadOptions.readahead_size is set.
if (lookup_context_.caller != TableReaderCaller::kCompaction) {
if (read_options_.readahead_size == 0) {
// Implicit auto readahead
num_file_reads_++;
if (num_file_reads_ >
BlockBasedTable::kMinNumFileReadsToStartAutoReadahead) {
if (!rep->file->use_direct_io() &&
(data_block_handle.offset() +
static_cast<size_t>(data_block_handle.size()) +
kBlockTrailerSize >
readahead_limit_)) {
// Buffered I/O
// Discarding the return status of Prefetch calls intentionally, as
// we can fallback to reading from disk if Prefetch fails.
rep->file->Prefetch(data_block_handle.offset(), readahead_size_);
readahead_limit_ = static_cast<size_t>(data_block_handle.offset() +
readahead_size_);
// Keep exponentially increasing readahead size until
// kMaxAutoReadaheadSize.
readahead_size_ = std::min(BlockBasedTable::kMaxAutoReadaheadSize,
readahead_size_ * 2);
} else if (rep->file->use_direct_io() && !prefetch_buffer_) {
// Direct I/O
// Let FilePrefetchBuffer take care of the readahead.
prefetch_buffer_.reset(new FilePrefetchBuffer(
rep->file.get(), BlockBasedTable::kInitAutoReadaheadSize,
BlockBasedTable::kMaxAutoReadaheadSize));
}
}
} else if (!prefetch_buffer_) {
// Explicit user requested readahead
// The actual condition is:
// if (read_options_.readahead_size != 0 && !prefetch_buffer_)
prefetch_buffer_.reset(new FilePrefetchBuffer(
rep->file.get(), read_options_.readahead_size,
read_options_.readahead_size));
}
} else if (!prefetch_buffer_) {
prefetch_buffer_.reset(
new FilePrefetchBuffer(rep->file.get(), compaction_readahead_size_,
compaction_readahead_size_));
}
Status s;
table_->NewDataBlockIterator<TBlockIter>(
read_options_, data_block_handle, &block_iter_, block_type_,
/*get_context=*/nullptr, &lookup_context_, s, prefetch_buffer_.get(),
/*for_compaction=*/lookup_context_.caller ==
TableReaderCaller::kCompaction);
block_iter_points_to_real_block_ = true;
CheckDataBlockWithinUpperBound();
}
}
template <class TBlockIter, typename TValue>
bool BlockBasedTableIterator<TBlockIter, TValue>::MaterializeCurrentBlock() {
assert(is_at_first_key_from_index_);
assert(!block_iter_points_to_real_block_);
assert(index_iter_->Valid());
is_at_first_key_from_index_ = false;
InitDataBlock();
assert(block_iter_points_to_real_block_);
block_iter_.SeekToFirst();
if (!block_iter_.Valid() ||
icomp_.Compare(block_iter_.key(),
index_iter_->value().first_internal_key) != 0) {
// Uh oh.
block_iter_.Invalidate(Status::Corruption(
"first key in index doesn't match first key in block"));
return false;
}
return true;
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::FindKeyForward() {
// This method's code is kept short to make it likely to be inlined.
assert(!is_out_of_bound_);
assert(block_iter_points_to_real_block_);
if (!block_iter_.Valid()) {
// This is the only call site of FindBlockForward(), but it's extracted into
// a separate method to keep FindKeyForward() short and likely to be
// inlined. When transitioning to a different block, we call
// FindBlockForward(), which is much longer and is probably not inlined.
FindBlockForward();
} else {
// This is the fast path that avoids a function call.
}
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::FindBlockForward() {
// TODO the while loop inherits from two-level-iterator. We don't know
// whether a block can be empty so it can be replaced by an "if".
do {
if (!block_iter_.status().ok()) {
return;
}
// Whether next data block is out of upper bound, if there is one.
const bool next_block_is_out_of_bound =
read_options_.iterate_upper_bound != nullptr &&
block_iter_points_to_real_block_ && !data_block_within_upper_bound_;
assert(!next_block_is_out_of_bound ||
user_comparator_.Compare(*read_options_.iterate_upper_bound,
index_iter_->user_key()) <= 0);
ResetDataIter();
index_iter_->Next();
if (next_block_is_out_of_bound) {
// The next block is out of bound. No need to read it.
TEST_SYNC_POINT_CALLBACK("BlockBasedTableIterator:out_of_bound", nullptr);
// We need to make sure this is not the last data block before setting
// is_out_of_bound_, since the index key for the last data block can be
// larger than smallest key of the next file on the same level.
if (index_iter_->Valid()) {
is_out_of_bound_ = true;
}
return;
}
if (!index_iter_->Valid()) {
return;
}
IndexValue v = index_iter_->value();
// TODO(kolmike): Remove the != kBlockCacheTier condition.
if (!v.first_internal_key.empty() &&
read_options_.read_tier != kBlockCacheTier) {
// Index contains the first key of the block. Defer reading the block.
is_at_first_key_from_index_ = true;
return;
}
InitDataBlock();
block_iter_.SeekToFirst();
} while (!block_iter_.Valid());
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::FindKeyBackward() {
while (!block_iter_.Valid()) {
if (!block_iter_.status().ok()) {
return;
}
ResetDataIter();
index_iter_->Prev();
if (index_iter_->Valid()) {
InitDataBlock();
block_iter_.SeekToLast();
} else {
return;
}
}
// We could have check lower bound here too, but we opt not to do it for
// code simplicity.
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::CheckOutOfBound() {
if (read_options_.iterate_upper_bound != nullptr && Valid()) {
is_out_of_bound_ = user_comparator_.Compare(
*read_options_.iterate_upper_bound, user_key()) <= 0;
}
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::CheckDataBlockWithinUpperBound() {
if (read_options_.iterate_upper_bound != nullptr &&
block_iter_points_to_real_block_) {
data_block_within_upper_bound_ =
(user_comparator_.Compare(*read_options_.iterate_upper_bound,
index_iter_->user_key()) > 0);
}
}
InternalIterator* BlockBasedTable::NewIterator(
const ReadOptions& read_options, const SliceTransform* prefix_extractor,
Arena* arena, bool skip_filters, TableReaderCaller caller, size_t compaction_readahead_size) {
BlockCacheLookupContext lookup_context{caller};
bool need_upper_bound_check =
PrefixExtractorChanged(rep_->table_properties.get(), prefix_extractor);
if (arena == nullptr) {
return new BlockBasedTableIterator<DataBlockIter>(
this, read_options, rep_->internal_comparator,
NewIndexIterator(
read_options,
need_upper_bound_check &&
rep_->index_type == BlockBasedTableOptions::kHashSearch,
/*input_iter=*/nullptr, /*get_context=*/nullptr, &lookup_context),
!skip_filters && !read_options.total_order_seek &&
prefix_extractor != nullptr,
need_upper_bound_check, prefix_extractor, BlockType::kData, caller,
compaction_readahead_size);
} else {
auto* mem =
arena->AllocateAligned(sizeof(BlockBasedTableIterator<DataBlockIter>));
return new (mem) BlockBasedTableIterator<DataBlockIter>(
this, read_options, rep_->internal_comparator,
NewIndexIterator(read_options, need_upper_bound_check &&
rep_->index_type == BlockBasedTableOptions::kHashSearch,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
&lookup_context),
!skip_filters && !read_options.total_order_seek &&
prefix_extractor != nullptr,
need_upper_bound_check, prefix_extractor, BlockType::kData, caller,
compaction_readahead_size);
}
}
FragmentedRangeTombstoneIterator* BlockBasedTable::NewRangeTombstoneIterator(
const ReadOptions& read_options) {
if (rep_->fragmented_range_dels == nullptr) {
return nullptr;
}
SequenceNumber snapshot = kMaxSequenceNumber;
if (read_options.snapshot != nullptr) {
snapshot = read_options.snapshot->GetSequenceNumber();
}
return new FragmentedRangeTombstoneIterator(
rep_->fragmented_range_dels, rep_->internal_comparator, snapshot);
}
bool BlockBasedTable::FullFilterKeyMayMatch(
const ReadOptions& read_options, FilterBlockReader* filter,
const Slice& internal_key, const bool no_io,
const SliceTransform* prefix_extractor, GetContext* get_context,
BlockCacheLookupContext* lookup_context) const {
if (filter == nullptr || filter->IsBlockBased()) {
return true;
}
Slice user_key = ExtractUserKey(internal_key);
const Slice* const const_ikey_ptr = &internal_key;
bool may_match = true;
if (rep_->whole_key_filtering) {
size_t ts_sz =
rep_->internal_comparator.user_comparator()->timestamp_size();
Slice user_key_without_ts = StripTimestampFromUserKey(user_key, ts_sz);
may_match =
filter->KeyMayMatch(user_key_without_ts, prefix_extractor, kNotValid,
no_io, const_ikey_ptr, get_context, lookup_context);
} else if (!read_options.total_order_seek && prefix_extractor &&
rep_->table_properties->prefix_extractor_name.compare(
prefix_extractor->Name()) == 0 &&
prefix_extractor->InDomain(user_key) &&
!filter->PrefixMayMatch(prefix_extractor->Transform(user_key),
prefix_extractor, kNotValid, no_io,
const_ikey_ptr, get_context,
lookup_context)) {
may_match = false;
}
if (may_match) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_FULL_POSITIVE);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_positive, 1, rep_->level);
}
return may_match;
}
void BlockBasedTable::FullFilterKeysMayMatch(
const ReadOptions& read_options, FilterBlockReader* filter,
MultiGetRange* range, const bool no_io,
const SliceTransform* prefix_extractor,
BlockCacheLookupContext* lookup_context) const {
if (filter == nullptr || filter->IsBlockBased()) {
return;
}
if (rep_->whole_key_filtering) {
filter->KeysMayMatch(range, prefix_extractor, kNotValid, no_io,
lookup_context);
} else if (!read_options.total_order_seek && prefix_extractor &&
rep_->table_properties->prefix_extractor_name.compare(
prefix_extractor->Name()) == 0) {
filter->PrefixesMayMatch(range, prefix_extractor, kNotValid, false,
lookup_context);
}
}
Status BlockBasedTable::Get(const ReadOptions& read_options, const Slice& key,
GetContext* get_context,
const SliceTransform* prefix_extractor,
bool skip_filters) {
assert(key.size() >= 8); // key must be internal key
assert(get_context != nullptr);
Status s;
const bool no_io = read_options.read_tier == kBlockCacheTier;
FilterBlockReader* const filter =
!skip_filters ? rep_->filter.get() : nullptr;
// First check the full filter
// If full filter not useful, Then go into each block
uint64_t tracing_get_id = get_context->get_tracing_get_id();
BlockCacheLookupContext lookup_context{
TableReaderCaller::kUserGet, tracing_get_id,
/*get_from_user_specified_snapshot=*/read_options.snapshot != nullptr};
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled()) {
// Trace the key since it contains both user key and sequence number.
lookup_context.referenced_key = key.ToString();
lookup_context.get_from_user_specified_snapshot =
read_options.snapshot != nullptr;
}
const bool may_match =
FullFilterKeyMayMatch(read_options, filter, key, no_io, prefix_extractor,
get_context, &lookup_context);
if (!may_match) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, 1, rep_->level);
} else {
IndexBlockIter iiter_on_stack;
// if prefix_extractor found in block differs from options, disable
// BlockPrefixIndex. Only do this check when index_type is kHashSearch.
bool need_upper_bound_check = false;
if (rep_->index_type == BlockBasedTableOptions::kHashSearch) {
need_upper_bound_check = PrefixExtractorChanged(
rep_->table_properties.get(), prefix_extractor);
}
auto iiter =
NewIndexIterator(read_options, need_upper_bound_check, &iiter_on_stack,
get_context, &lookup_context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr.reset(iiter);
}
size_t ts_sz =
rep_->internal_comparator.user_comparator()->timestamp_size();
bool matched = false; // if such user key mathced a key in SST
bool done = false;
for (iiter->Seek(key); iiter->Valid() && !done; iiter->Next()) {
IndexValue v = iiter->value();
bool not_exist_in_filter =
filter != nullptr && filter->IsBlockBased() == true &&
!filter->KeyMayMatch(ExtractUserKeyAndStripTimestamp(key, ts_sz),
prefix_extractor, v.handle.offset(), no_io,
/*const_ikey_ptr=*/nullptr, get_context,
&lookup_context);
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);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, 1, rep_->level);
break;
}
if (!v.first_internal_key.empty() && !skip_filters &&
UserComparatorWrapper(rep_->internal_comparator.user_comparator())
.Compare(ExtractUserKey(key),
ExtractUserKey(v.first_internal_key)) < 0) {
// The requested key falls between highest key in previous block and
// lowest key in current block.
break;
}
BlockCacheLookupContext lookup_data_block_context{
TableReaderCaller::kUserGet, tracing_get_id,
/*get_from_user_specified_snapshot=*/read_options.snapshot !=
nullptr};
bool does_referenced_key_exist = false;
DataBlockIter biter;
uint64_t referenced_data_size = 0;
NewDataBlockIterator<DataBlockIter>(
read_options, v.handle, &biter, BlockType::kData, get_context,
&lookup_data_block_context,
/*s=*/Status(), /*prefetch_buffer*/ nullptr);
if (no_io && 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
get_context->MarkKeyMayExist();
break;
}
if (!biter.status().ok()) {
s = biter.status();
break;
}
bool may_exist = biter.SeekForGet(key);
// If user-specified timestamp is supported, we cannot end the search
// just because hash index lookup indicates the key+ts does not exist.
if (!may_exist && ts_sz == 0) {
// HashSeek cannot find the key this block and the the iter is not
// the end of the block, i.e. cannot be in the following blocks
// either. In this case, the seek_key cannot be found, so we break
// from the top level for-loop.
done = true;
} else {
// Call the *saver function on each entry/block until it returns false
for (; biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (!get_context->SaveValue(
parsed_key, biter.value(), &matched,
biter.IsValuePinned() ? &biter : nullptr)) {
if (get_context->State() == GetContext::GetState::kFound) {
does_referenced_key_exist = true;
referenced_data_size = biter.key().size() + biter.value().size();
}
done = true;
break;
}
}
s = biter.status();
}
// Write the block cache access record.
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled()) {
// Avoid making copy of block_key, cf_name, and referenced_key when
// constructing the access record.
Slice referenced_key;
if (does_referenced_key_exist) {
referenced_key = biter.key();
} else {
referenced_key = key;
}
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", lookup_data_block_context.block_type,
lookup_data_block_context.block_size, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_data_block_context.caller,
lookup_data_block_context.is_cache_hit,
lookup_data_block_context.no_insert,
lookup_data_block_context.get_id,
lookup_data_block_context.get_from_user_specified_snapshot,
/*referenced_key=*/"", referenced_data_size,
lookup_data_block_context.num_keys_in_block,
does_referenced_key_exist);
block_cache_tracer_->WriteBlockAccess(
access_record, lookup_data_block_context.block_key,
rep_->cf_name_for_tracing(), referenced_key);
}
if (done) {
// Avoid the extra Next which is expensive in two-level indexes
break;
}
}
if (matched && filter != nullptr && !filter->IsBlockBased()) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_FULL_TRUE_POSITIVE);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_true_positive, 1,
rep_->level);
}
if (s.ok()) {
s = iiter->status();
}
}
return s;
}
using MultiGetRange = MultiGetContext::Range;
void BlockBasedTable::MultiGet(const ReadOptions& read_options,
const MultiGetRange* mget_range,
const SliceTransform* prefix_extractor,
bool skip_filters) {
FilterBlockReader* const filter =
!skip_filters ? rep_->filter.get() : nullptr;
MultiGetRange sst_file_range(*mget_range, mget_range->begin(),
mget_range->end());
// First check the full filter
// If full filter not useful, Then go into each block
const bool no_io = read_options.read_tier == kBlockCacheTier;
uint64_t tracing_mget_id = BlockCacheTraceHelper::kReservedGetId;
if (!sst_file_range.empty() && sst_file_range.begin()->get_context) {
tracing_mget_id = sst_file_range.begin()->get_context->get_tracing_get_id();
}
BlockCacheLookupContext lookup_context{
TableReaderCaller::kUserMultiGet, tracing_mget_id,
/*get_from_user_specified_snapshot=*/read_options.snapshot != nullptr};
FullFilterKeysMayMatch(read_options, filter, &sst_file_range, no_io,
prefix_extractor, &lookup_context);
if (skip_filters || !sst_file_range.empty()) {
IndexBlockIter iiter_on_stack;
// if prefix_extractor found in block differs from options, disable
// BlockPrefixIndex. Only do this check when index_type is kHashSearch.
bool need_upper_bound_check = false;
if (rep_->index_type == BlockBasedTableOptions::kHashSearch) {
need_upper_bound_check = PrefixExtractorChanged(
rep_->table_properties.get(), prefix_extractor);
}
auto iiter =
NewIndexIterator(read_options, need_upper_bound_check, &iiter_on_stack,
sst_file_range.begin()->get_context, &lookup_context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr.reset(iiter);
}
uint64_t offset = std::numeric_limits<uint64_t>::max();
autovector<BlockHandle, MultiGetContext::MAX_BATCH_SIZE> block_handles;
autovector<CachableEntry<Block>, MultiGetContext::MAX_BATCH_SIZE> results;
autovector<Status, MultiGetContext::MAX_BATCH_SIZE> statuses;
static const size_t kMultiGetReadStackBufSize = 8192;
char stack_buf[kMultiGetReadStackBufSize];
std::unique_ptr<char[]> block_buf;
{
MultiGetRange data_block_range(sst_file_range, sst_file_range.begin(),
sst_file_range.end());
CachableEntry<UncompressionDict> uncompression_dict;
Status uncompression_dict_status;
if (rep_->uncompression_dict_reader) {
uncompression_dict_status =
rep_->uncompression_dict_reader->GetOrReadUncompressionDictionary(
nullptr /* prefetch_buffer */, no_io,
sst_file_range.begin()->get_context, &lookup_context,
&uncompression_dict);
}
const UncompressionDict& dict = uncompression_dict.GetValue()
? *uncompression_dict.GetValue()
: UncompressionDict::GetEmptyDict();
size_t total_len = 0;
ReadOptions ro = read_options;
ro.read_tier = kBlockCacheTier;
for (auto miter = data_block_range.begin();
miter != data_block_range.end(); ++miter) {
const Slice& key = miter->ikey;
iiter->Seek(miter->ikey);
IndexValue v;
if (iiter->Valid()) {
v = iiter->value();
}
if (!iiter->Valid() ||
(!v.first_internal_key.empty() && !skip_filters &&
UserComparatorWrapper(rep_->internal_comparator.user_comparator())
.Compare(ExtractUserKey(key),
ExtractUserKey(v.first_internal_key)) < 0)) {
// The requested key falls between highest key in previous block and
// lowest key in current block.
*(miter->s) = iiter->status();
data_block_range.SkipKey(miter);
sst_file_range.SkipKey(miter);
continue;
}
if (!uncompression_dict_status.ok()) {
*(miter->s) = uncompression_dict_status;
data_block_range.SkipKey(miter);
sst_file_range.SkipKey(miter);
continue;
}
statuses.emplace_back();
results.emplace_back();
if (v.handle.offset() == offset) {
// We're going to reuse the block for this key later on. No need to
// look it up now. Place a null handle
block_handles.emplace_back(BlockHandle::NullBlockHandle());
continue;
}
// Lookup the cache for the given data block referenced by an index
// iterator value (i.e BlockHandle). If it exists in the cache,
// initialize block to the contents of the data block.
offset = v.handle.offset();
BlockHandle handle = v.handle;
BlockCacheLookupContext lookup_data_block_context(
TableReaderCaller::kUserMultiGet);
Status s = RetrieveBlock(
nullptr, ro, handle, dict, &(results.back()), BlockType::kData,
miter->get_context, &lookup_data_block_context,
/* for_compaction */ false, /* use_cache */ true);
if (s.IsIncomplete()) {
s = Status::OK();
}
if (s.ok() && !results.back().IsEmpty()) {
// Found it in the cache. Add NULL handle to indicate there is
// nothing to read from disk
block_handles.emplace_back(BlockHandle::NullBlockHandle());
} else {
block_handles.emplace_back(handle);
total_len += handle.size();
}
}
if (total_len) {
char* scratch = nullptr;
// If the blocks need to be uncompressed and we don't need the
// compressed blocks, then we can use a contiguous block of
// memory to read in all the blocks as it will be temporary
// storage
// 1. If blocks are compressed and compressed block cache is there,
// alloc heap bufs
// 2. If blocks are uncompressed, alloc heap bufs
// 3. If blocks are compressed and no compressed block cache, use
// stack buf
if (rep_->table_options.block_cache_compressed == nullptr &&
rep_->blocks_maybe_compressed) {
if (total_len <= kMultiGetReadStackBufSize) {
scratch = stack_buf;
} else {
scratch = new char[total_len];
block_buf.reset(scratch);
}
}
RetrieveMultipleBlocks(read_options, &data_block_range, &block_handles,
&statuses, &results, scratch, dict);
}
}
DataBlockIter first_biter;
DataBlockIter next_biter;
size_t idx_in_batch = 0;
for (auto miter = sst_file_range.begin(); miter != sst_file_range.end();
++miter) {
Status s;
GetContext* get_context = miter->get_context;
const Slice& key = miter->ikey;
bool matched = false; // if such user key matched a key in SST
bool done = false;
bool first_block = true;
do {
DataBlockIter* biter = nullptr;
bool reusing_block = true;
uint64_t referenced_data_size = 0;
bool does_referenced_key_exist = false;
BlockCacheLookupContext lookup_data_block_context(
TableReaderCaller::kUserMultiGet, tracing_mget_id,
/*get_from_user_specified_snapshot=*/read_options.snapshot !=
nullptr);
if (first_block) {
if (!block_handles[idx_in_batch].IsNull() ||
!results[idx_in_batch].IsEmpty()) {
first_biter.Invalidate(Status::OK());
NewDataBlockIterator<DataBlockIter>(
read_options, results[idx_in_batch], &first_biter,
statuses[idx_in_batch]);
reusing_block = false;
}
biter = &first_biter;
idx_in_batch++;
} else {
IndexValue v = iiter->value();
if (!v.first_internal_key.empty() && !skip_filters &&
UserComparatorWrapper(rep_->internal_comparator.user_comparator())
.Compare(ExtractUserKey(key),
ExtractUserKey(v.first_internal_key)) < 0) {
// The requested key falls between highest key in previous block and
// lowest key in current block.
break;
}
next_biter.Invalidate(Status::OK());
NewDataBlockIterator<DataBlockIter>(
read_options, iiter->value().handle, &next_biter,
BlockType::kData, get_context, &lookup_data_block_context,
Status(), nullptr);
biter = &next_biter;
reusing_block = false;
}
if (read_options.read_tier == kBlockCacheTier &&
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
get_context->MarkKeyMayExist();
break;
}
if (!biter->status().ok()) {
s = biter->status();
break;
}
bool may_exist = biter->SeekForGet(key);
if (!may_exist) {
// HashSeek cannot find the key this block and the the iter is not
// the end of the block, i.e. cannot be in the following blocks
// either. In this case, the seek_key cannot be found, so we break
// from the top level for-loop.
break;
}
// Call the *saver function on each entry/block until it returns false
for (; biter->Valid(); biter->Next()) {
ParsedInternalKey parsed_key;
Cleanable dummy;
Cleanable* value_pinner = nullptr;
if (!ParseInternalKey(biter->key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (biter->IsValuePinned()) {
if (reusing_block) {
Cache* block_cache = rep_->table_options.block_cache.get();
assert(biter->cache_handle() != nullptr);
block_cache->Ref(biter->cache_handle());
dummy.RegisterCleanup(&ReleaseCachedEntry, block_cache,
biter->cache_handle());
value_pinner = &dummy;
} else {
value_pinner = biter;
}
}
if (!get_context->SaveValue(parsed_key, biter->value(), &matched,
value_pinner)) {
if (get_context->State() == GetContext::GetState::kFound) {
does_referenced_key_exist = true;
referenced_data_size =
biter->key().size() + biter->value().size();
}
done = true;
break;
}
s = biter->status();
}
// Write the block cache access.
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled()) {
// Avoid making copy of block_key, cf_name, and referenced_key when
// constructing the access record.
Slice referenced_key;
if (does_referenced_key_exist) {
referenced_key = biter->key();
} else {
referenced_key = key;
}
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", lookup_data_block_context.block_type,
lookup_data_block_context.block_size, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_data_block_context.caller,
lookup_data_block_context.is_cache_hit,
lookup_data_block_context.no_insert,
lookup_data_block_context.get_id,
lookup_data_block_context.get_from_user_specified_snapshot,
/*referenced_key=*/"", referenced_data_size,
lookup_data_block_context.num_keys_in_block,
does_referenced_key_exist);
block_cache_tracer_->WriteBlockAccess(
access_record, lookup_data_block_context.block_key,
rep_->cf_name_for_tracing(), referenced_key);
}
s = biter->status();
if (done) {
// Avoid the extra Next which is expensive in two-level indexes
break;
}
if (first_block) {
iiter->Seek(key);
}
first_block = false;
iiter->Next();
} while (iiter->Valid());
if (matched && filter != nullptr && !filter->IsBlockBased()) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_FULL_TRUE_POSITIVE);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_true_positive, 1,
rep_->level);
}
if (s.ok()) {
s = iiter->status();
}
*(miter->s) = s;
}
}
}
Status BlockBasedTable::Prefetch(const Slice* const begin,
const Slice* const end) {
auto& comparator = rep_->internal_comparator;
UserComparatorWrapper user_comparator(comparator.user_comparator());
// pre-condition
if (begin && end && comparator.Compare(*begin, *end) > 0) {
return Status::InvalidArgument(*begin, *end);
}
BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
IndexBlockIter iiter_on_stack;
auto iiter = NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
&iiter_on_stack, /*get_context=*/nullptr,
&lookup_context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr = std::unique_ptr<InternalIteratorBase<IndexValue>>(iiter);
}
if (!iiter->status().ok()) {
// error opening index iterator
return iiter->status();
}
// indicates if we are on the last page that need to be pre-fetched
bool prefetching_boundary_page = false;
for (begin ? iiter->Seek(*begin) : iiter->SeekToFirst(); iiter->Valid();
iiter->Next()) {
BlockHandle block_handle = iiter->value().handle;
const bool is_user_key = !rep_->index_key_includes_seq;
if (end &&
((!is_user_key && comparator.Compare(iiter->key(), *end) >= 0) ||
(is_user_key &&
user_comparator.Compare(iiter->key(), ExtractUserKey(*end)) >= 0))) {
if (prefetching_boundary_page) {
break;
}
// The index entry represents the last key in the data block.
// We should load this page into memory as well, but no more
prefetching_boundary_page = true;
}
// Load the block specified by the block_handle into the block cache
DataBlockIter biter;
NewDataBlockIterator<DataBlockIter>(
ReadOptions(), block_handle, &biter, /*type=*/BlockType::kData,
/*get_context=*/nullptr, &lookup_context, Status(),
/*prefetch_buffer=*/nullptr);
if (!biter.status().ok()) {
// there was an unexpected error while pre-fetching
return biter.status();
}
}
return Status::OK();
}
Status BlockBasedTable::VerifyChecksum(const ReadOptions& read_options,
TableReaderCaller caller) {
Status s;
// Check Meta blocks
std::unique_ptr<Block> meta;
std::unique_ptr<InternalIterator> meta_iter;
s = ReadMetaBlock(nullptr /* prefetch buffer */, &meta, &meta_iter);
if (s.ok()) {
s = VerifyChecksumInMetaBlocks(meta_iter.get());
if (!s.ok()) {
return s;
}
} else {
return s;
}
// Check Data blocks
IndexBlockIter iiter_on_stack;
BlockCacheLookupContext context{caller};
InternalIteratorBase<IndexValue>* iiter = NewIndexIterator(
read_options, /*disable_prefix_seek=*/false, &iiter_on_stack,
/*get_context=*/nullptr, &context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr = std::unique_ptr<InternalIteratorBase<IndexValue>>(iiter);
}
if (!iiter->status().ok()) {
// error opening index iterator
return iiter->status();
}
s = VerifyChecksumInBlocks(read_options, iiter);
return s;
}
Status BlockBasedTable::VerifyChecksumInBlocks(
const ReadOptions& read_options,
InternalIteratorBase<IndexValue>* index_iter) {
Status s;
// We are scanning the whole file, so no need to do exponential
// increasing of the buffer size.
size_t readahead_size = (read_options.readahead_size != 0)
? read_options.readahead_size
: kMaxAutoReadaheadSize;
FilePrefetchBuffer prefetch_buffer(rep_->file.get(), readahead_size,
readahead_size);
for (index_iter->SeekToFirst(); index_iter->Valid(); index_iter->Next()) {
s = index_iter->status();
if (!s.ok()) {
break;
}
BlockHandle handle = index_iter->value().handle;
BlockContents contents;
BlockFetcher block_fetcher(
rep_->file.get(), &prefetch_buffer, rep_->footer, ReadOptions(), handle,
&contents, rep_->ioptions, false /* decompress */,
false /*maybe_compressed*/, BlockType::kData,
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options);
s = block_fetcher.ReadBlockContents();
if (!s.ok()) {
break;
}
}
return s;
}
BlockType BlockBasedTable::GetBlockTypeForMetaBlockByName(
const Slice& meta_block_name) {
if (meta_block_name.starts_with(kFilterBlockPrefix) ||
meta_block_name.starts_with(kFullFilterBlockPrefix) ||
meta_block_name.starts_with(kPartitionedFilterBlockPrefix)) {
return BlockType::kFilter;
}
if (meta_block_name == kPropertiesBlock) {
return BlockType::kProperties;
}
if (meta_block_name == kCompressionDictBlock) {
return BlockType::kCompressionDictionary;
}
if (meta_block_name == kRangeDelBlock) {
return BlockType::kRangeDeletion;
}
if (meta_block_name == kHashIndexPrefixesBlock) {
return BlockType::kHashIndexPrefixes;
}
if (meta_block_name == kHashIndexPrefixesMetadataBlock) {
return BlockType::kHashIndexMetadata;
}
assert(false);
return BlockType::kInvalid;
}
Status BlockBasedTable::VerifyChecksumInMetaBlocks(
InternalIteratorBase<Slice>* index_iter) {
Status s;
for (index_iter->SeekToFirst(); index_iter->Valid(); index_iter->Next()) {
s = index_iter->status();
if (!s.ok()) {
break;
}
BlockHandle handle;
Slice input = index_iter->value();
s = handle.DecodeFrom(&input);
BlockContents contents;
const Slice meta_block_name = index_iter->key();
BlockFetcher block_fetcher(
rep_->file.get(), nullptr /* prefetch buffer */, rep_->footer,
ReadOptions(), handle, &contents, rep_->ioptions,
false /* decompress */, false /*maybe_compressed*/,
GetBlockTypeForMetaBlockByName(meta_block_name),
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options);
s = block_fetcher.ReadBlockContents();
if (s.IsCorruption() && meta_block_name == kPropertiesBlock) {
TableProperties* table_properties;
s = TryReadPropertiesWithGlobalSeqno(nullptr /* prefetch_buffer */,
index_iter->value(),
&table_properties);
delete table_properties;
}
if (!s.ok()) {
break;
}
}
return s;
}
bool BlockBasedTable::TEST_BlockInCache(const BlockHandle& handle) const {
assert(rep_ != nullptr);
Cache* const cache = rep_->table_options.block_cache.get();
if (cache == nullptr) {
return false;
}
char cache_key_storage[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
Slice cache_key =
GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size, handle,
cache_key_storage);
Cache::Handle* const cache_handle = cache->Lookup(cache_key);
if (cache_handle == nullptr) {
return false;
}
cache->Release(cache_handle);
return true;
}
bool BlockBasedTable::TEST_KeyInCache(const ReadOptions& options,
const Slice& key) {
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter(NewIndexIterator(
options, /*need_upper_bound_check=*/false, /*input_iter=*/nullptr,
/*get_context=*/nullptr, /*lookup_context=*/nullptr));
iiter->Seek(key);
assert(iiter->Valid());
return TEST_BlockInCache(iiter->value().handle);
}
// REQUIRES: The following fields of rep_ should have already been populated:
// 1. file
// 2. index_handle,
// 3. options
// 4. internal_comparator
// 5. index_type
Status BlockBasedTable::CreateIndexReader(
FilePrefetchBuffer* prefetch_buffer,
InternalIterator* preloaded_meta_index_iter, bool use_cache, bool prefetch,
bool pin, BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
// kHashSearch requires non-empty prefix_extractor but bypass checking
// prefix_extractor here since we have no access to MutableCFOptions.
// Add need_upper_bound_check flag in BlockBasedTable::NewIndexIterator.
// If prefix_extractor does not match prefix_extractor_name from table
// properties, turn off Hash Index by setting total_order_seek to true
switch (rep_->index_type) {
case BlockBasedTableOptions::kTwoLevelIndexSearch: {
return PartitionIndexReader::Create(this, prefetch_buffer, use_cache,
prefetch, pin, lookup_context,
index_reader);
}
case BlockBasedTableOptions::kBinarySearch:
case BlockBasedTableOptions::kBinarySearchWithFirstKey: {
return BinarySearchIndexReader::Create(this, prefetch_buffer, use_cache,
prefetch, pin, lookup_context,
index_reader);
}
case BlockBasedTableOptions::kHashSearch: {
std::unique_ptr<Block> meta_guard;
std::unique_ptr<InternalIterator> meta_iter_guard;
auto meta_index_iter = preloaded_meta_index_iter;
if (meta_index_iter == nullptr) {
auto s = ReadMetaBlock(prefetch_buffer, &meta_guard, &meta_iter_guard);
if (!s.ok()) {
// we simply fall back to binary search in case there is any
// problem with prefix hash index loading.
ROCKS_LOG_WARN(rep_->ioptions.info_log,
"Unable to read the metaindex block."
" Fall back to binary search index.");
return BinarySearchIndexReader::Create(this, prefetch_buffer,
use_cache, prefetch, pin,
lookup_context, index_reader);
}
meta_index_iter = meta_iter_guard.get();
}
return HashIndexReader::Create(this, prefetch_buffer, meta_index_iter,
use_cache, prefetch, pin, lookup_context,
index_reader);
}
default: {
std::string error_message =
"Unrecognized index type: " + ToString(rep_->index_type);
return Status::InvalidArgument(error_message.c_str());
}
}
}
uint64_t BlockBasedTable::ApproximateOffsetOf(
const InternalIteratorBase<IndexValue>& index_iter) const {
uint64_t result = 0;
if (index_iter.Valid()) {
BlockHandle handle = index_iter.value().handle;
result = handle.offset();
} else {
// The iterator is past the last key in the file. If table_properties is not
// available, approximate the offset by returning the offset of the
// metaindex block (which is right near the end of the file).
if (rep_->table_properties) {
result = rep_->table_properties->data_size;
}
// table_properties is not present in the table.
if (result == 0) {
result = rep_->footer.metaindex_handle().offset();
}
}
return result;
}
uint64_t BlockBasedTable::ApproximateOffsetOf(const Slice& key,
TableReaderCaller caller) {
BlockCacheLookupContext context(caller);
IndexBlockIter iiter_on_stack;
auto index_iter =
NewIndexIterator(ReadOptions(), /*disable_prefix_seek=*/false,
/*input_iter=*/&iiter_on_stack, /*get_context=*/nullptr,
/*lookup_context=*/&context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (index_iter != &iiter_on_stack) {
iiter_unique_ptr.reset(index_iter);
}
index_iter->Seek(key);
return ApproximateOffsetOf(*index_iter);
}
uint64_t BlockBasedTable::ApproximateSize(const Slice& start, const Slice& end,
TableReaderCaller caller) {
assert(rep_->internal_comparator.Compare(start, end) <= 0);
BlockCacheLookupContext context(caller);
IndexBlockIter iiter_on_stack;
auto index_iter =
NewIndexIterator(ReadOptions(), /*disable_prefix_seek=*/false,
/*input_iter=*/&iiter_on_stack, /*get_context=*/nullptr,
/*lookup_context=*/&context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (index_iter != &iiter_on_stack) {
iiter_unique_ptr.reset(index_iter);
}
index_iter->Seek(start);
uint64_t start_offset = ApproximateOffsetOf(*index_iter);
index_iter->Seek(end);
uint64_t end_offset = ApproximateOffsetOf(*index_iter);
assert(end_offset >= start_offset);
return end_offset - start_offset;
}
bool BlockBasedTable::TEST_FilterBlockInCache() const {
assert(rep_ != nullptr);
return TEST_BlockInCache(rep_->filter_handle);
}
bool BlockBasedTable::TEST_IndexBlockInCache() const {
assert(rep_ != nullptr);
return TEST_BlockInCache(rep_->footer.index_handle());
}
Status BlockBasedTable::GetKVPairsFromDataBlocks(
std::vector<KVPairBlock>* kv_pair_blocks) {
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_contex=*/nullptr));
Status s = blockhandles_iter->status();
if (!s.ok()) {
// Cannot read Index Block
return s;
}
for (blockhandles_iter->SeekToFirst(); blockhandles_iter->Valid();
blockhandles_iter->Next()) {
s = blockhandles_iter->status();
if (!s.ok()) {
break;
}
std::unique_ptr<InternalIterator> datablock_iter;
datablock_iter.reset(NewDataBlockIterator<DataBlockIter>(
ReadOptions(), blockhandles_iter->value().handle,
/*input_iter=*/nullptr, /*type=*/BlockType::kData,
/*get_context=*/nullptr, /*lookup_context=*/nullptr, Status(),
/*prefetch_buffer=*/nullptr));
s = datablock_iter->status();
if (!s.ok()) {
// Error reading the block - Skipped
continue;
}
KVPairBlock kv_pair_block;
for (datablock_iter->SeekToFirst(); datablock_iter->Valid();
datablock_iter->Next()) {
s = datablock_iter->status();
if (!s.ok()) {
// Error reading the block - Skipped
break;
}
const Slice& key = datablock_iter->key();
const Slice& value = datablock_iter->value();
std::string key_copy = std::string(key.data(), key.size());
std::string value_copy = std::string(value.data(), value.size());
kv_pair_block.push_back(
std::make_pair(std::move(key_copy), std::move(value_copy)));
}
kv_pair_blocks->push_back(std::move(kv_pair_block));
}
return Status::OK();
}
Status BlockBasedTable::DumpTable(WritableFile* out_file) {
// Output Footer
out_file->Append(
"Footer Details:\n"
"--------------------------------------\n"
" ");
out_file->Append(rep_->footer.ToString().c_str());
out_file->Append("\n");
// Output MetaIndex
out_file->Append(
"Metaindex Details:\n"
"--------------------------------------\n");
std::unique_ptr<Block> meta;
std::unique_ptr<InternalIterator> meta_iter;
Status s = ReadMetaBlock(nullptr /* prefetch_buffer */, &meta, &meta_iter);
if (s.ok()) {
for (meta_iter->SeekToFirst(); meta_iter->Valid(); meta_iter->Next()) {
s = meta_iter->status();
if (!s.ok()) {
return s;
}
if (meta_iter->key() == rocksdb::kPropertiesBlock) {
out_file->Append(" Properties block handle: ");
out_file->Append(meta_iter->value().ToString(true).c_str());
out_file->Append("\n");
} else if (meta_iter->key() == rocksdb::kCompressionDictBlock) {
out_file->Append(" Compression dictionary block handle: ");
out_file->Append(meta_iter->value().ToString(true).c_str());
out_file->Append("\n");
} else if (strstr(meta_iter->key().ToString().c_str(),
"filter.rocksdb.") != nullptr) {
out_file->Append(" Filter block handle: ");
out_file->Append(meta_iter->value().ToString(true).c_str());
out_file->Append("\n");
} else if (meta_iter->key() == rocksdb::kRangeDelBlock) {
out_file->Append(" Range deletion block handle: ");
out_file->Append(meta_iter->value().ToString(true).c_str());
out_file->Append("\n");
}
}
out_file->Append("\n");
} else {
return s;
}
// Output TableProperties
const rocksdb::TableProperties* table_properties;
table_properties = rep_->table_properties.get();
if (table_properties != nullptr) {
out_file->Append(
"Table Properties:\n"
"--------------------------------------\n"
" ");
out_file->Append(table_properties->ToString("\n ", ": ").c_str());
out_file->Append("\n");
}
if (rep_->filter) {
out_file->Append(
"Filter Details:\n"
"--------------------------------------\n"
" ");
out_file->Append(rep_->filter->ToString().c_str());
out_file->Append("\n");
}
// Output Index block
s = DumpIndexBlock(out_file);
if (!s.ok()) {
return s;
}
// Output compression dictionary
if (rep_->uncompression_dict_reader) {
CachableEntry<UncompressionDict> uncompression_dict;
s = rep_->uncompression_dict_reader->GetOrReadUncompressionDictionary(
nullptr /* prefetch_buffer */, false /* no_io */,
nullptr /* get_context */, nullptr /* lookup_context */,
&uncompression_dict);
if (!s.ok()) {
return s;
}
assert(uncompression_dict.GetValue());
const Slice& raw_dict = uncompression_dict.GetValue()->GetRawDict();
out_file->Append(
"Compression Dictionary:\n"
"--------------------------------------\n");
out_file->Append(" size (bytes): ");
out_file->Append(rocksdb::ToString(raw_dict.size()));
out_file->Append("\n\n");
out_file->Append(" HEX ");
out_file->Append(raw_dict.ToString(true).c_str());
out_file->Append("\n\n");
}
// Output range deletions block
auto* range_del_iter = NewRangeTombstoneIterator(ReadOptions());
if (range_del_iter != nullptr) {
range_del_iter->SeekToFirst();
if (range_del_iter->Valid()) {
out_file->Append(
"Range deletions:\n"
"--------------------------------------\n"
" ");
for (; range_del_iter->Valid(); range_del_iter->Next()) {
DumpKeyValue(range_del_iter->key(), range_del_iter->value(), out_file);
}
out_file->Append("\n");
}
delete range_del_iter;
}
// Output Data blocks
s = DumpDataBlocks(out_file);
return s;
}
Status BlockBasedTable::DumpIndexBlock(WritableFile* out_file) {
out_file->Append(
"Index Details:\n"
"--------------------------------------\n");
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_contex=*/nullptr));
Status s = blockhandles_iter->status();
if (!s.ok()) {
out_file->Append("Can not read Index Block \n\n");
return s;
}
out_file->Append(" Block key hex dump: Data block handle\n");
out_file->Append(" Block key ascii\n\n");
for (blockhandles_iter->SeekToFirst(); blockhandles_iter->Valid();
blockhandles_iter->Next()) {
s = blockhandles_iter->status();
if (!s.ok()) {
break;
}
Slice key = blockhandles_iter->key();
Slice user_key;
InternalKey ikey;
if (!rep_->index_key_includes_seq) {
user_key = key;
} else {
ikey.DecodeFrom(key);
user_key = ikey.user_key();
}
out_file->Append(" HEX ");
out_file->Append(user_key.ToString(true).c_str());
out_file->Append(": ");
out_file->Append(blockhandles_iter->value()
.ToString(true, rep_->index_has_first_key)
.c_str());
out_file->Append("\n");
std::string str_key = user_key.ToString();
std::string res_key("");
char cspace = ' ';
for (size_t i = 0; i < str_key.size(); i++) {
res_key.append(&str_key[i], 1);
res_key.append(1, cspace);
}
out_file->Append(" ASCII ");
out_file->Append(res_key.c_str());
out_file->Append("\n ------\n");
}
out_file->Append("\n");
return Status::OK();
}
Status BlockBasedTable::DumpDataBlocks(WritableFile* out_file) {
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_contex=*/nullptr));
Status s = blockhandles_iter->status();
if (!s.ok()) {
out_file->Append("Can not read Index Block \n\n");
return s;
}
uint64_t datablock_size_min = std::numeric_limits<uint64_t>::max();
uint64_t datablock_size_max = 0;
uint64_t datablock_size_sum = 0;
size_t block_id = 1;
for (blockhandles_iter->SeekToFirst(); blockhandles_iter->Valid();
block_id++, blockhandles_iter->Next()) {
s = blockhandles_iter->status();
if (!s.ok()) {
break;
}
BlockHandle bh = blockhandles_iter->value().handle;
uint64_t datablock_size = bh.size();
datablock_size_min = std::min(datablock_size_min, datablock_size);
datablock_size_max = std::max(datablock_size_max, datablock_size);
datablock_size_sum += datablock_size;
out_file->Append("Data Block # ");
out_file->Append(rocksdb::ToString(block_id));
out_file->Append(" @ ");
out_file->Append(blockhandles_iter->value().handle.ToString(true).c_str());
out_file->Append("\n");
out_file->Append("--------------------------------------\n");
std::unique_ptr<InternalIterator> datablock_iter;
datablock_iter.reset(NewDataBlockIterator<DataBlockIter>(
ReadOptions(), blockhandles_iter->value().handle,
/*input_iter=*/nullptr, /*type=*/BlockType::kData,
/*get_context=*/nullptr, /*lookup_context=*/nullptr, Status(),
/*prefetch_buffer=*/nullptr));
s = datablock_iter->status();
if (!s.ok()) {
out_file->Append("Error reading the block - Skipped \n\n");
continue;
}
for (datablock_iter->SeekToFirst(); datablock_iter->Valid();
datablock_iter->Next()) {
s = datablock_iter->status();
if (!s.ok()) {
out_file->Append("Error reading the block - Skipped \n");
break;
}
DumpKeyValue(datablock_iter->key(), datablock_iter->value(), out_file);
}
out_file->Append("\n");
}
uint64_t num_datablocks = block_id - 1;
if (num_datablocks) {
double datablock_size_avg =
static_cast<double>(datablock_size_sum) / num_datablocks;
out_file->Append("Data Block Summary:\n");
out_file->Append("--------------------------------------");
out_file->Append("\n # data blocks: ");
out_file->Append(rocksdb::ToString(num_datablocks));
out_file->Append("\n min data block size: ");
out_file->Append(rocksdb::ToString(datablock_size_min));
out_file->Append("\n max data block size: ");
out_file->Append(rocksdb::ToString(datablock_size_max));
out_file->Append("\n avg data block size: ");
out_file->Append(rocksdb::ToString(datablock_size_avg));
out_file->Append("\n");
}
return Status::OK();
}
void BlockBasedTable::DumpKeyValue(const Slice& key, const Slice& value,
WritableFile* out_file) {
InternalKey ikey;
ikey.DecodeFrom(key);
out_file->Append(" HEX ");
out_file->Append(ikey.user_key().ToString(true).c_str());
out_file->Append(": ");
out_file->Append(value.ToString(true).c_str());
out_file->Append("\n");
std::string str_key = ikey.user_key().ToString();
std::string str_value = value.ToString();
std::string res_key(""), res_value("");
char cspace = ' ';
for (size_t i = 0; i < str_key.size(); i++) {
if (str_key[i] == '\0') {
res_key.append("\\0", 2);
} else {
res_key.append(&str_key[i], 1);
}
res_key.append(1, cspace);
}
for (size_t i = 0; i < str_value.size(); i++) {
if (str_value[i] == '\0') {
res_value.append("\\0", 2);
} else {
res_value.append(&str_value[i], 1);
}
res_value.append(1, cspace);
}
out_file->Append(" ASCII ");
out_file->Append(res_key.c_str());
out_file->Append(": ");
out_file->Append(res_value.c_str());
out_file->Append("\n ------\n");
}
} // namespace rocksdb
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