dolysis/rocksdb
3
0
Fork 0
mirror of https://github.com/facebook/rocksdb.git synced 2024-11-26 16:30:56 +00:00
Code Issues Packages Projects Releases Wiki Activity
rocksdb/table/block_based_table_reader.cc
Siying Dong e9e0101ca4 Move test related files under util/ to test_util/ (#5377) 
Summary:
There are too many types of files under util/. Some test related files don't belong to there or just are just loosely related. Mo
ve them to a new directory test_util/, so that util/ is cleaner.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5377

Differential Revision: D15551366

Pulled By: siying

fbshipit-source-id: 0f5c8653832354ef8caa31749c0143815d719e2c
2019-05-30 11:25:51 -07:00

3696 lines
141 KiB
C++
Raw Blame History

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/block_based_table_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 "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.h"
#include "table/block_based_filter_block.h"
#include "table/block_based_table_factory.h"
#include "table/block_fetcher.h"
#include "table/block_prefix_index.h"
#include "table/filter_block.h"
#include "table/format.h"
#include "table/full_filter_block.h"
#include "table/get_context.h"
#include "table/internal_iterator.h"
#include "table/meta_blocks.h"
#include "table/multiget_context.h"
#include "table/partitioned_filter_block.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 "util/coding.h"
#include "util/crc32c.h"
#include "util/file_reader_writer.h"
#include "util/stop_watch.h"
#include "util/string_util.h"
#include "test_util/sync_point.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;
BlockBasedTable::~BlockBasedTable() {
Close();
delete rep_;
}
std::atomic<uint64_t> BlockBasedTable::next_cache_key_id_(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.
Status ReadBlockFromFile(
RandomAccessFileReader* file, FilePrefetchBuffer* prefetch_buffer,
const Footer& footer, const ReadOptions& options, const BlockHandle& handle,
std::unique_ptr<Block>* result, const ImmutableCFOptions& ioptions,
bool do_uncompress, bool maybe_compressed,
const UncompressionDict& uncompression_dict,
const PersistentCacheOptions& cache_options, SequenceNumber global_seqno,
size_t read_amp_bytes_per_bit, MemoryAllocator* memory_allocator) {
BlockContents contents;
BlockFetcher block_fetcher(file, prefetch_buffer, footer, options, handle,
&contents, ioptions, do_uncompress,
maybe_compressed, uncompression_dict,
cache_options, memory_allocator);
Status s = block_fetcher.ReadBlockContents();
if (s.ok()) {
result->reset(new Block(std::move(contents), global_seqno,
read_amp_bytes_per_bit, ioptions.statistics));
}
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;
}
void DeleteCachedFilterEntry(const Slice& key, void* value);
void DeleteCachedIndexEntry(const Slice& key, void* value);
void DeleteCachedUncompressionDictEntry(const Slice& key, void* value);
// Release the cached entry and decrement its ref count.
void ReleaseCachedEntry(void* arg, void* h) {
Cache* cache = reinterpret_cast<Cache*>(arg);
Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
cache->Release(handle);
}
// 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 */);
}
Slice GetCacheKeyFromOffset(const char* cache_key_prefix,
size_t cache_key_prefix_size, uint64_t offset,
char* cache_key) {
assert(cache_key != nullptr);
assert(cache_key_prefix_size != 0);
assert(cache_key_prefix_size <= BlockBasedTable::kMaxCacheKeyPrefixSize);
memcpy(cache_key, cache_key_prefix, cache_key_prefix_size);
char* end = EncodeVarint64(cache_key + cache_key_prefix_size, offset);
return Slice(cache_key, static_cast<size_t>(end - cache_key));
}
Cache::Handle* GetEntryFromCache(Cache* block_cache, const Slice& key,
int level, Tickers block_cache_miss_ticker,
Tickers block_cache_hit_ticker,
uint64_t* block_cache_miss_stats,
uint64_t* block_cache_hit_stats,
Statistics* statistics,
GetContext* get_context) {
auto cache_handle = block_cache->Lookup(key, statistics);
if (cache_handle != nullptr) {
PERF_COUNTER_ADD(block_cache_hit_count, 1);
PERF_COUNTER_BY_LEVEL_ADD(block_cache_hit_count, 1,
static_cast<uint32_t>(level));
if (get_context != nullptr) {
// overall cache hit
get_context->get_context_stats_.num_cache_hit++;
// total bytes read from cache
get_context->get_context_stats_.num_cache_bytes_read +=
block_cache->GetUsage(cache_handle);
// block-type specific cache hit
(*block_cache_hit_stats)++;
} else {
// overall cache hit
RecordTick(statistics, BLOCK_CACHE_HIT);
// total bytes read from cache
RecordTick(statistics, BLOCK_CACHE_BYTES_READ,
block_cache->GetUsage(cache_handle));
RecordTick(statistics, block_cache_hit_ticker);
}
} else {
PERF_COUNTER_BY_LEVEL_ADD(block_cache_miss_count, 1,
static_cast<uint32_t>(level));
if (get_context != nullptr) {
// overall cache miss
get_context->get_context_stats_.num_cache_miss++;
// block-type specific cache miss
(*block_cache_miss_stats)++;
} else {
RecordTick(statistics, BLOCK_CACHE_MISS);
RecordTick(statistics, block_cache_miss_ticker);
}
}
return cache_handle;
}
// 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;
}
}
} // namespace
// Index that allows binary search lookup in a two-level index structure.
class PartitionIndexReader : public IndexReader {
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(BlockBasedTable* table, RandomAccessFileReader* file,
FilePrefetchBuffer* prefetch_buffer,
const Footer& footer, const BlockHandle& index_handle,
const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icomparator,
IndexReader** index_reader,
const PersistentCacheOptions& cache_options,
const int level, const bool index_key_includes_seq,
const bool index_value_is_full,
MemoryAllocator* memory_allocator) {
std::unique_ptr<Block> index_block;
auto s = ReadBlockFromFile(
file, prefetch_buffer, footer, ReadOptions(), index_handle,
&index_block, ioptions, true /* decompress */,
true /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
cache_options, kDisableGlobalSequenceNumber,
0 /* read_amp_bytes_per_bit */, memory_allocator);
if (s.ok()) {
*index_reader = new PartitionIndexReader(
table, icomparator, std::move(index_block), ioptions.statistics,
level, index_key_includes_seq, index_value_is_full);
}
return s;
}
// return a two-level iterator: first level is on the partition index
InternalIteratorBase<BlockHandle>* NewIterator(
IndexBlockIter* /*iter*/ = nullptr, bool /*dont_care*/ = true,
bool fill_cache = true) override {
Statistics* kNullStats = nullptr;
// Filters are already checked before seeking the index
if (!partition_map_.empty()) {
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
return NewTwoLevelIterator(
new BlockBasedTable::PartitionedIndexIteratorState(
table_, &partition_map_, index_key_includes_seq_,
index_value_is_full_),
index_block_->NewIterator<IndexBlockIter>(
icomparator_, icomparator_->user_comparator(), nullptr,
kNullStats, true, index_key_includes_seq_, index_value_is_full_));
} else {
auto ro = ReadOptions();
ro.fill_cache = fill_cache;
bool kIsIndex = true;
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
return new BlockBasedTableIterator<IndexBlockIter, BlockHandle>(
table_, ro, *icomparator_,
index_block_->NewIterator<IndexBlockIter>(
icomparator_, icomparator_->user_comparator(), nullptr,
kNullStats, true, index_key_includes_seq_, index_value_is_full_),
false, true, /* prefix_extractor */ nullptr, kIsIndex,
index_key_includes_seq_, index_value_is_full_);
}
// 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
auto rep = table_->rep_;
IndexBlockIter biter;
BlockHandle handle;
Statistics* kNullStats = nullptr;
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
index_block_->NewIterator<IndexBlockIter>(
icomparator_, icomparator_->user_comparator(), &biter, kNullStats, true,
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();
uint64_t prefetch_off = handle.offset();
// Read the last block's offset
biter.SeekToLast();
if (!biter.Valid()) {
// Empty index.
return;
}
handle = biter.value();
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 = table_->rep_->file;
prefetch_buffer.reset(new FilePrefetchBuffer());
Status 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();
CachableEntry<Block> block;
const bool is_index = true;
// TODO: Support counter batch update for partitioned index and
// filter blocks
s = table_->MaybeReadBlockAndLoadToCache(
prefetch_buffer.get(), rep, ro, handle,
UncompressionDict::GetEmptyDict(), &block, is_index,
nullptr /* get_context */);
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 size() const override { return index_block_->size(); }
size_t usable_size() const override { return index_block_->usable_size(); }
size_t ApproximateMemoryUsage() const override {
assert(index_block_);
size_t usage = index_block_->ApproximateMemoryUsage();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size((void*)this);
#else
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
// TODO(myabandeh): more accurate estimate of partition_map_ mem usage
return usage;
}
private:
PartitionIndexReader(BlockBasedTable* table,
const InternalKeyComparator* icomparator,
std::unique_ptr<Block>&& index_block, Statistics* stats,
const int /*level*/, const bool index_key_includes_seq,
const bool index_value_is_full)
: IndexReader(icomparator, stats),
table_(table),
index_block_(std::move(index_block)),
index_key_includes_seq_(index_key_includes_seq),
index_value_is_full_(index_value_is_full) {
assert(index_block_ != nullptr);
}
BlockBasedTable* table_;
std::unique_ptr<Block> index_block_;
std::unordered_map<uint64_t, CachableEntry<Block>> partition_map_;
const bool index_key_includes_seq_;
const bool index_value_is_full_;
};
// 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 IndexReader {
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(RandomAccessFileReader* file,
FilePrefetchBuffer* prefetch_buffer,
const Footer& footer, const BlockHandle& index_handle,
const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icomparator,
IndexReader** index_reader,
const PersistentCacheOptions& cache_options,
const bool index_key_includes_seq,
const bool index_value_is_full,
MemoryAllocator* memory_allocator) {
std::unique_ptr<Block> index_block;
auto s = ReadBlockFromFile(
file, prefetch_buffer, footer, ReadOptions(), index_handle,
&index_block, ioptions, true /* decompress */,
true /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
cache_options, kDisableGlobalSequenceNumber,
0 /* read_amp_bytes_per_bit */, memory_allocator);
if (s.ok()) {
*index_reader = new BinarySearchIndexReader(
icomparator, std::move(index_block), ioptions.statistics,
index_key_includes_seq, index_value_is_full);
}
return s;
}
InternalIteratorBase<BlockHandle>* NewIterator(
IndexBlockIter* iter = nullptr, bool /*dont_care*/ = true,
bool /*dont_care*/ = true) override {
Statistics* kNullStats = nullptr;
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
return index_block_->NewIterator<IndexBlockIter>(
icomparator_, icomparator_->user_comparator(), iter, kNullStats, true,
index_key_includes_seq_, index_value_is_full_);
}
size_t size() const override { return index_block_->size(); }
size_t usable_size() const override { return index_block_->usable_size(); }
size_t ApproximateMemoryUsage() const override {
assert(index_block_);
size_t usage = index_block_->ApproximateMemoryUsage();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size((void*)this);
#else
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
return usage;
}
private:
BinarySearchIndexReader(const InternalKeyComparator* icomparator,
std::unique_ptr<Block>&& index_block,
Statistics* stats, const bool index_key_includes_seq,
const bool index_value_is_full)
: IndexReader(icomparator, stats),
index_block_(std::move(index_block)),
index_key_includes_seq_(index_key_includes_seq),
index_value_is_full_(index_value_is_full) {
assert(index_block_ != nullptr);
}
std::unique_ptr<Block> index_block_;
const bool index_key_includes_seq_;
const bool index_value_is_full_;
};
// Index that leverages an internal hash table to quicken the lookup for a given
// key.
class HashIndexReader : public IndexReader {
public:
static Status Create(
const SliceTransform* hash_key_extractor, const Footer& footer,
RandomAccessFileReader* file, FilePrefetchBuffer* prefetch_buffer,
const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icomparator, const BlockHandle& index_handle,
InternalIterator* meta_index_iter, IndexReader** index_reader,
bool /*hash_index_allow_collision*/,
const PersistentCacheOptions& cache_options,
const bool index_key_includes_seq, const bool index_value_is_full,
MemoryAllocator* memory_allocator) {
std::unique_ptr<Block> index_block;
auto s = ReadBlockFromFile(
file, prefetch_buffer, footer, ReadOptions(), index_handle,
&index_block, ioptions, true /* decompress */,
true /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
cache_options, kDisableGlobalSequenceNumber,
0 /* read_amp_bytes_per_bit */, memory_allocator);
if (!s.ok()) {
return s;
}
// 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.
auto new_index_reader = new HashIndexReader(
icomparator, std::move(index_block), ioptions.statistics,
index_key_includes_seq, index_value_is_full);
*index_reader = new_index_reader;
// Get prefixes block
BlockHandle prefixes_handle;
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();
}
// 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*/, 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*/, 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(hash_key_extractor, prefixes_contents.data,
prefixes_meta_contents.data, &prefix_index);
// TODO: log error
if (s.ok()) {
new_index_reader->prefix_index_.reset(prefix_index);
}
return Status::OK();
}
InternalIteratorBase<BlockHandle>* NewIterator(
IndexBlockIter* iter = nullptr, bool total_order_seek = true,
bool /*dont_care*/ = true) override {
Statistics* kNullStats = nullptr;
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
return index_block_->NewIterator<IndexBlockIter>(
icomparator_, icomparator_->user_comparator(), iter, kNullStats,
total_order_seek, index_key_includes_seq_, index_value_is_full_,
false /* block_contents_pinned */, prefix_index_.get());
}
size_t size() const override { return index_block_->size(); }
size_t usable_size() const override { return index_block_->usable_size(); }
size_t ApproximateMemoryUsage() const override {
assert(index_block_);
size_t usage = index_block_->ApproximateMemoryUsage();
usage += prefixes_contents_.usable_size();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size((void*)this);
#else
if (prefix_index_) {
usage += prefix_index_->ApproximateMemoryUsage();
}
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
return usage;
}
private:
HashIndexReader(const InternalKeyComparator* icomparator,
std::unique_ptr<Block>&& index_block, Statistics* stats,
const bool index_key_includes_seq,
const bool index_value_is_full)
: IndexReader(icomparator, stats),
index_block_(std::move(index_block)),
index_key_includes_seq_(index_key_includes_seq),
index_value_is_full_(index_value_is_full) {
assert(index_block_ != nullptr);
}
~HashIndexReader() override {}
std::unique_ptr<Block> index_block_;
std::unique_ptr<BlockPrefixIndex> prefix_index_;
BlockContents prefixes_contents_;
const bool index_key_includes_seq_;
const bool index_value_is_full_;
};
// Helper function to setup the cache key's prefix for the Table.
void BlockBasedTable::SetupCacheKeyPrefix(Rep* rep, uint64_t file_size) {
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);
// Create dummy offset of index reader which is beyond the file size.
rep->dummy_index_reader_offset =
file_size + rep->table_options.block_cache->NewId();
}
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) {
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.
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->index_type = table_options.index_type;
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, file_size);
std::unique_ptr<BlockBasedTable> new_table(new BlockBasedTable(rep));
// 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 = ReadMetaBlock(rep, prefetch_buffer.get(), &meta, &meta_iter);
if (!s.ok()) {
return s;
}
s = ReadPropertiesBlock(rep, prefetch_buffer.get(), meta_iter.get(),
largest_seqno);
if (!s.ok()) {
return s;
}
s = ReadRangeDelBlock(rep, prefetch_buffer.get(), meta_iter.get(),
internal_comparator);
if (!s.ok()) {
return s;
}
s = PrefetchIndexAndFilterBlocks(rep, prefetch_buffer.get(), meta_iter.get(),
new_table.get(), prefix_extractor,
prefetch_all, table_options, level,
prefetch_index_and_filter_in_cache);
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(
Rep* rep, 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(
Rep* rep, 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(
rep, 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);
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(
Rep* rep, FilePrefetchBuffer* prefetch_buffer, InternalIterator* meta_iter,
const InternalKeyComparator& internal_comparator) {
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>(
rep, read_options, range_del_handle, nullptr /* input_iter */,
false /* is_index */, true /* key_includes_seq */,
true /* index_key_is_full */, nullptr /* get_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::ReadCompressionDictBlock(
Rep* rep, FilePrefetchBuffer* prefetch_buffer,
std::unique_ptr<const BlockContents>* compression_dict_block) {
assert(compression_dict_block != nullptr);
Status s;
if (!rep->compression_dict_handle.IsNull()) {
std::unique_ptr<BlockContents> compression_dict_cont{new BlockContents()};
PersistentCacheOptions cache_options;
ReadOptions read_options;
read_options.verify_checksums = true;
BlockFetcher compression_block_fetcher(
rep->file.get(), prefetch_buffer, rep->footer, read_options,
rep->compression_dict_handle, compression_dict_cont.get(),
rep->ioptions, false /* decompress */, false /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(), cache_options);
s = compression_block_fetcher.ReadBlockContents();
if (!s.ok()) {
ROCKS_LOG_WARN(
rep->ioptions.info_log,
"Encountered error while reading data from compression dictionary "
"block %s",
s.ToString().c_str());
} else {
*compression_dict_block = std::move(compression_dict_cont);
}
}
return s;
}
Status BlockBasedTable::PrefetchIndexAndFilterBlocks(
Rep* rep, FilePrefetchBuffer* prefetch_buffer, InternalIterator* meta_iter,
BlockBasedTable* new_table, const SliceTransform* prefix_extractor,
bool prefetch_all, const BlockBasedTableOptions& table_options,
const int level, const bool prefetch_index_and_filter_in_cache) {
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;
s = SeekToCompressionDictBlock(meta_iter, &found_compression_dict,
&rep->compression_dict_handle);
}
bool need_upper_bound_check =
PrefixExtractorChanged(rep->table_properties.get(), prefix_extractor);
BlockBasedTableOptions::IndexType index_type = new_table->UpdateIndexType();
// prefetch the first level of index
const bool prefetch_index =
prefetch_all ||
(table_options.pin_top_level_index_and_filter &&
index_type == BlockBasedTableOptions::kTwoLevelIndexSearch);
// 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 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;
// pin the first level of index
const bool pin_index =
pin_all || (table_options.pin_top_level_index_and_filter &&
index_type == BlockBasedTableOptions::kTwoLevelIndexSearch);
// 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);
// pre-fetching of blocks is turned on
// Will use block cache for meta-blocks access
// Always prefetch index and filter for level 0
// TODO(ajkr): also prefetch compression dictionary block
if (table_options.cache_index_and_filter_blocks) {
assert(table_options.block_cache != nullptr);
if (prefetch_index) {
// Hack: Call NewIndexIterator() to implicitly add index to the
// block_cache
CachableEntry<IndexReader> index_entry;
// check prefix_extractor match only if hash based index is used
bool disable_prefix_seek =
rep->index_type == BlockBasedTableOptions::kHashSearch &&
need_upper_bound_check;
if (s.ok()) {
std::unique_ptr<InternalIteratorBase<BlockHandle>> iter(
new_table->NewIndexIterator(ReadOptions(), disable_prefix_seek,
nullptr, &index_entry));
s = iter->status();
}
if (s.ok()) {
// This is the first call to NewIndexIterator() since we're in Open().
// On success it should give us ownership of the `CachableEntry` by
// populating `index_entry`.
assert(index_entry.GetValue() != nullptr);
if (prefetch_all) {
index_entry.GetValue()->CacheDependencies(pin_all);
}
if (pin_index) {
rep->index_entry = std::move(index_entry);
}
}
}
if (s.ok() && prefetch_filter) {
// Hack: Call GetFilter() to implicitly add filter to the block_cache
auto filter_entry =
new_table->GetFilter(rep->table_prefix_extractor.get());
if (filter_entry.GetValue() != nullptr && prefetch_all) {
filter_entry.GetValue()->CacheDependencies(
pin_all, rep->table_prefix_extractor.get());
}
// if pin_filter is true then save it in rep_->filter_entry; it will be
// released in the destructor only, hence it will be pinned in the
// cache while this reader is alive
if (pin_filter) {
rep->filter_entry = std::move(filter_entry);
}
}
} else {
// If we don't use block cache for meta-block access, we'll pre-load these
// blocks, which will kept in member variables in Rep and with a same life-
// time as this table object.
IndexReader* index_reader = nullptr;
if (s.ok()) {
s = new_table->CreateIndexReader(prefetch_buffer, &index_reader,
meta_iter, level);
}
std::unique_ptr<const BlockContents> compression_dict_block;
if (s.ok()) {
rep->index_reader.reset(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_index_and_filter_in_cache || level == 0) {
rep->index_reader->CacheDependencies(pin_all);
}
// Set filter block
if (rep->filter_policy) {
const bool is_a_filter_partition = true;
auto filter = new_table->ReadFilter(prefetch_buffer, rep->filter_handle,
!is_a_filter_partition,
rep->table_prefix_extractor.get());
rep->filter.reset(filter);
// Refer to the comment above about paritioned indexes always being
// cached
if (filter && (prefetch_index_and_filter_in_cache || level == 0)) {
filter->CacheDependencies(pin_all, rep->table_prefix_extractor.get());
}
}
s = ReadCompressionDictBlock(rep, prefetch_buffer,
&compression_dict_block);
} else {
delete index_reader;
}
if (s.ok() && !rep->compression_dict_handle.IsNull()) {
assert(compression_dict_block != nullptr);
// TODO(ajkr): find a way to avoid the `compression_dict_block` data copy
rep->uncompression_dict.reset(new UncompressionDict(
compression_dict_block->data.ToString(),
rep->blocks_definitely_zstd_compressed, rep->ioptions.statistics));
}
}
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) {
usage += rep_->uncompression_dict->ApproximateMemoryUsage();
}
return usage;
}
// Load the meta-block from the file. On success, return the loaded meta block
// and its iterator.
Status BlockBasedTable::ReadMetaBlock(Rep* rep,
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*/,
UncompressionDict::GetEmptyDict(), rep->persistent_cache_options,
kDisableGlobalSequenceNumber, 0 /* read_amp_bytes_per_bit */,
GetMemoryAllocator(rep->table_options));
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()->NewIterator<DataBlockIter>(
BytewiseComparator(), BytewiseComparator()));
return Status::OK();
}
Status BlockBasedTable::GetDataBlockFromCache(
const Slice& block_cache_key, const Slice& compressed_block_cache_key,
Cache* block_cache, Cache* block_cache_compressed, Rep* rep,
const ReadOptions& read_options, CachableEntry<Block>* block,
const UncompressionDict& uncompression_dict, size_t read_amp_bytes_per_bit,
bool is_index, GetContext* get_context) {
assert(block);
assert(block->IsEmpty());
Status s;
BlockContents* compressed_block = nullptr;
Cache::Handle* block_cache_compressed_handle = nullptr;
Statistics* statistics = rep->ioptions.statistics;
// Lookup uncompressed cache first
if (block_cache != nullptr) {
auto cache_handle = GetEntryFromCache(
block_cache, block_cache_key, rep->level,
is_index ? BLOCK_CACHE_INDEX_MISS : BLOCK_CACHE_DATA_MISS,
is_index ? BLOCK_CACHE_INDEX_HIT : BLOCK_CACHE_DATA_HIT,
get_context
? (is_index ? &get_context->get_context_stats_.num_cache_index_miss
: &get_context->get_context_stats_.num_cache_data_miss)
: nullptr,
get_context
? (is_index ? &get_context->get_context_stats_.num_cache_index_hit
: &get_context->get_context_stats_.num_cache_data_hit)
: nullptr,
statistics, get_context);
if (cache_handle != nullptr) {
block->SetCachedValue(
reinterpret_cast<Block*>(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);
// 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<Block> block_holder(
new Block(std::move(contents), rep->get_global_seqno(is_index),
read_amp_bytes_per_bit, statistics)); // 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<Block>,
&cache_handle);
#ifndef NDEBUG
block_cache->TEST_mark_as_data_block(block_cache_key, charge);
#endif // NDEBUG
if (s.ok()) {
assert(cache_handle != nullptr);
block->SetCachedValue(block_holder.release(), block_cache,
cache_handle);
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_add++;
get_context->get_context_stats_.num_cache_bytes_write += charge;
} else {
RecordTick(statistics, BLOCK_CACHE_ADD);
RecordTick(statistics, BLOCK_CACHE_BYTES_WRITE, charge);
}
if (is_index) {
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_index_add++;
get_context->get_context_stats_.num_cache_index_bytes_insert +=
charge;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_ADD);
RecordTick(statistics, BLOCK_CACHE_INDEX_BYTES_INSERT, charge);
}
} else {
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_data_add++;
get_context->get_context_stats_.num_cache_data_bytes_insert +=
charge;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_ADD);
RecordTick(statistics, BLOCK_CACHE_DATA_BYTES_INSERT, 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;
}
Status BlockBasedTable::PutDataBlockToCache(
const Slice& block_cache_key, const Slice& compressed_block_cache_key,
Cache* block_cache, Cache* block_cache_compressed,
const ReadOptions& /*read_options*/, const ImmutableCFOptions& ioptions,
CachableEntry<Block>* cached_block, BlockContents* raw_block_contents,
CompressionType raw_block_comp_type, uint32_t format_version,
const UncompressionDict& uncompression_dict, SequenceNumber seq_no,
size_t read_amp_bytes_per_bit, MemoryAllocator* memory_allocator,
bool is_index, Cache::Priority priority, GetContext* get_context) {
assert(cached_block);
assert(cached_block->IsEmpty());
assert(raw_block_comp_type == kNoCompression ||
block_cache_compressed != nullptr);
Status s;
Statistics* statistics = ioptions.statistics;
std::unique_ptr<Block> 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(new Block(std::move(uncompressed_block_contents), seq_no,
read_amp_bytes_per_bit, statistics));
} else {
block_holder.reset(new Block(std::move(*raw_block_contents), seq_no,
read_amp_bytes_per_bit, statistics));
}
// 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<Block>,
&cache_handle, priority);
#ifndef NDEBUG
block_cache->TEST_mark_as_data_block(block_cache_key, charge);
#endif // NDEBUG
if (s.ok()) {
assert(cache_handle != nullptr);
cached_block->SetCachedValue(block_holder.release(), block_cache,
cache_handle);
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_add++;
get_context->get_context_stats_.num_cache_bytes_write += charge;
} else {
RecordTick(statistics, BLOCK_CACHE_ADD);
RecordTick(statistics, BLOCK_CACHE_BYTES_WRITE, charge);
}
if (is_index) {
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_index_add++;
get_context->get_context_stats_.num_cache_index_bytes_insert +=
charge;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_ADD);
RecordTick(statistics, BLOCK_CACHE_INDEX_BYTES_INSERT, charge);
}
} else {
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_data_add++;
get_context->get_context_stats_.num_cache_data_bytes_insert += charge;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_ADD);
RecordTick(statistics, BLOCK_CACHE_DATA_BYTES_INSERT, charge);
}
}
assert(reinterpret_cast<Block*>(block_cache->Value(
cached_block->GetCacheHandle())) == cached_block->GetValue());
} else {
RecordTick(statistics, BLOCK_CACHE_ADD_FAILURES);
}
} else {
cached_block->SetOwnedValue(block_holder.release());
}
return s;
}
FilterBlockReader* BlockBasedTable::ReadFilter(
FilePrefetchBuffer* prefetch_buffer, const BlockHandle& filter_handle,
const bool is_a_filter_partition,
const SliceTransform* prefix_extractor) const {
auto& rep = rep_;
// TODO: We might want to unify with ReadBlockFromFile() if we start
// requiring checksum verification in Table::Open.
if (rep->filter_type == Rep::FilterType::kNoFilter) {
return nullptr;
}
BlockContents block;
BlockFetcher block_fetcher(
rep->file.get(), prefetch_buffer, rep->footer, ReadOptions(),
filter_handle, &block, rep->ioptions, false /* decompress */,
false /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
rep->persistent_cache_options, GetMemoryAllocator(rep->table_options));
Status s = block_fetcher.ReadBlockContents();
if (!s.ok()) {
// Error reading the block
return nullptr;
}
assert(rep->filter_policy);
auto filter_type = rep->filter_type;
if (rep->filter_type == Rep::FilterType::kPartitionedFilter &&
is_a_filter_partition) {
filter_type = Rep::FilterType::kFullFilter;
}
switch (filter_type) {
case Rep::FilterType::kPartitionedFilter: {
return new PartitionedFilterBlockReader(
rep->prefix_filtering ? prefix_extractor : nullptr,
rep->whole_key_filtering, std::move(block), nullptr,
rep->ioptions.statistics, rep->internal_comparator, this,
rep_->table_properties == nullptr ||
rep_->table_properties->index_key_is_user_key == 0,
rep_->table_properties == nullptr ||
rep_->table_properties->index_value_is_delta_encoded == 0);
}
case Rep::FilterType::kBlockFilter:
return new BlockBasedFilterBlockReader(
rep->prefix_filtering ? prefix_extractor : nullptr,
rep->table_options, rep->whole_key_filtering, std::move(block),
rep->ioptions.statistics);
case Rep::FilterType::kFullFilter: {
auto filter_bits_reader =
rep->filter_policy->GetFilterBitsReader(block.data);
assert(filter_bits_reader != nullptr);
return new FullFilterBlockReader(
rep->prefix_filtering ? prefix_extractor : nullptr,
rep->whole_key_filtering, std::move(block), filter_bits_reader,
rep->ioptions.statistics);
}
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 nullptr;
}
}
CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
const SliceTransform* prefix_extractor, FilePrefetchBuffer* prefetch_buffer,
bool no_io, GetContext* get_context) const {
const BlockHandle& filter_blk_handle = rep_->filter_handle;
const bool is_a_filter_partition = true;
return GetFilter(prefetch_buffer, filter_blk_handle, !is_a_filter_partition,
no_io, get_context, prefix_extractor);
}
CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
FilePrefetchBuffer* prefetch_buffer, const BlockHandle& filter_blk_handle,
const bool is_a_filter_partition, bool no_io, GetContext* get_context,
const SliceTransform* prefix_extractor) const {
// If cache_index_and_filter_blocks is false, filter should be pre-populated.
// We will return rep_->filter anyway. rep_->filter can be nullptr if filter
// read fails at Open() time. We don't want to reload again since it will
// most probably fail again.
if (!is_a_filter_partition &&
!rep_->table_options.cache_index_and_filter_blocks) {
return {rep_->filter.get(), nullptr /* cache */,
nullptr /* cache_handle */, false /* own_value */};
}
Cache* block_cache = rep_->table_options.block_cache.get();
if (rep_->filter_policy == nullptr /* do not use filter */ ||
block_cache == nullptr /* no block cache at all */) {
return CachableEntry<FilterBlockReader>();
}
if (!is_a_filter_partition && rep_->filter_entry.IsCached()) {
return {rep_->filter_entry.GetValue(), nullptr /* cache */,
nullptr /* cache_handle */, false /* own_value */};
}
PERF_TIMER_GUARD(read_filter_block_nanos);
// Fetching from the cache
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
auto key = GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
filter_blk_handle, cache_key);
Statistics* statistics = rep_->ioptions.statistics;
Cache::Handle* cache_handle = GetEntryFromCache(
block_cache, key, rep_->level, BLOCK_CACHE_FILTER_MISS,
BLOCK_CACHE_FILTER_HIT,
get_context ? &get_context->get_context_stats_.num_cache_filter_miss
: nullptr,
get_context ? &get_context->get_context_stats_.num_cache_filter_hit
: nullptr,
statistics, get_context);
FilterBlockReader* filter = nullptr;
if (cache_handle != nullptr) {
PERF_COUNTER_ADD(block_cache_filter_hit_count, 1);
filter =
reinterpret_cast<FilterBlockReader*>(block_cache->Value(cache_handle));
} else if (no_io) {
// Do not invoke any io.
return CachableEntry<FilterBlockReader>();
} else {
filter = ReadFilter(prefetch_buffer, filter_blk_handle,
is_a_filter_partition, prefix_extractor);
if (filter != nullptr) {
size_t usage = filter->ApproximateMemoryUsage();
Status s = block_cache->Insert(
key, filter, usage, &DeleteCachedFilterEntry, &cache_handle,
rep_->table_options.cache_index_and_filter_blocks_with_high_priority
? Cache::Priority::HIGH
: Cache::Priority::LOW);
if (s.ok()) {
PERF_COUNTER_ADD(filter_block_read_count, 1);
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_add++;
get_context->get_context_stats_.num_cache_bytes_write += usage;
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_ADD);
RecordTick(statistics, BLOCK_CACHE_BYTES_WRITE, usage);
RecordTick(statistics, BLOCK_CACHE_FILTER_ADD);
RecordTick(statistics, BLOCK_CACHE_FILTER_BYTES_INSERT, usage);
}
} else {
RecordTick(statistics, BLOCK_CACHE_ADD_FAILURES);
delete filter;
return CachableEntry<FilterBlockReader>();
}
}
}
return {filter, cache_handle ? block_cache : nullptr, cache_handle,
false /* own_value */};
}
CachableEntry<UncompressionDict>
BlockBasedTable::GetUncompressionDict(Rep* rep,
FilePrefetchBuffer* prefetch_buffer,
bool no_io, GetContext* get_context) {
if (!rep->table_options.cache_index_and_filter_blocks) {
// block cache is either disabled or not used for meta-blocks. In either
// case, BlockBasedTableReader is the owner of the uncompression dictionary.
return {rep->uncompression_dict.get(), nullptr /* cache */,
nullptr /* cache_handle */, false /* own_value */};
}
if (rep->compression_dict_handle.IsNull()) {
return CachableEntry<UncompressionDict>();
}
char cache_key_buf[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
auto cache_key =
GetCacheKey(rep->cache_key_prefix, rep->cache_key_prefix_size,
rep->compression_dict_handle, cache_key_buf);
auto cache_handle = GetEntryFromCache(
rep->table_options.block_cache.get(), cache_key, rep->level,
BLOCK_CACHE_COMPRESSION_DICT_MISS, BLOCK_CACHE_COMPRESSION_DICT_HIT,
get_context
? &get_context->get_context_stats_.num_cache_compression_dict_miss
: nullptr,
get_context
? &get_context->get_context_stats_.num_cache_compression_dict_hit
: nullptr,
rep->ioptions.statistics, get_context);
UncompressionDict* dict = nullptr;
if (cache_handle != nullptr) {
dict = reinterpret_cast<UncompressionDict*>(
rep->table_options.block_cache->Value(cache_handle));
} else if (no_io) {
// Do not invoke any io.
} else {
std::unique_ptr<const BlockContents> compression_dict_block;
Status s =
ReadCompressionDictBlock(rep, prefetch_buffer, &compression_dict_block);
size_t usage = 0;
if (s.ok()) {
assert(compression_dict_block != nullptr);
// TODO(ajkr): find a way to avoid the `compression_dict_block` data copy
dict = new UncompressionDict(compression_dict_block->data.ToString(),
rep->blocks_definitely_zstd_compressed,
rep->ioptions.statistics);
usage = dict->ApproximateMemoryUsage();
s = rep->table_options.block_cache->Insert(
cache_key, dict, usage, &DeleteCachedUncompressionDictEntry,
&cache_handle,
rep->table_options.cache_index_and_filter_blocks_with_high_priority
? Cache::Priority::HIGH
: Cache::Priority::LOW);
}
if (s.ok()) {
PERF_COUNTER_ADD(compression_dict_block_read_count, 1);
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_add++;
get_context->get_context_stats_.num_cache_bytes_write += usage;
get_context->get_context_stats_.num_cache_compression_dict_add++;
get_context->get_context_stats_
.num_cache_compression_dict_bytes_insert += usage;
} else {
RecordTick(rep->ioptions.statistics, BLOCK_CACHE_ADD);
RecordTick(rep->ioptions.statistics, BLOCK_CACHE_BYTES_WRITE, usage);
RecordTick(rep->ioptions.statistics, BLOCK_CACHE_COMPRESSION_DICT_ADD);
RecordTick(rep->ioptions.statistics,
BLOCK_CACHE_COMPRESSION_DICT_BYTES_INSERT, usage);
}
} else {
// There should be no way to get here if block cache insertion succeeded.
// Though it is still possible something failed earlier.
RecordTick(rep->ioptions.statistics, BLOCK_CACHE_ADD_FAILURES);
delete dict;
dict = nullptr;
assert(cache_handle == nullptr);
}
}
return {dict, cache_handle ? rep->table_options.block_cache.get() : nullptr,
cache_handle, false /* own_value */};
}
// 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<BlockHandle>* BlockBasedTable::NewIndexIterator(
const ReadOptions& read_options, bool disable_prefix_seek,
IndexBlockIter* input_iter, CachableEntry<IndexReader>* index_entry,
GetContext* get_context) {
// index reader has already been pre-populated.
if (rep_->index_reader) {
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
return rep_->index_reader->NewIterator(
input_iter, read_options.total_order_seek || disable_prefix_seek,
read_options.fill_cache);
}
// we have a pinned index block
if (rep_->index_entry.IsCached()) {
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
return rep_->index_entry.GetValue()->NewIterator(
input_iter, read_options.total_order_seek || disable_prefix_seek,
read_options.fill_cache);
}
PERF_TIMER_GUARD(read_index_block_nanos);
const bool no_io = read_options.read_tier == kBlockCacheTier;
Cache* block_cache = rep_->table_options.block_cache.get();
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
auto key =
GetCacheKeyFromOffset(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
rep_->dummy_index_reader_offset, cache_key);
Statistics* statistics = rep_->ioptions.statistics;
auto cache_handle = GetEntryFromCache(
block_cache, key, rep_->level, BLOCK_CACHE_INDEX_MISS,
BLOCK_CACHE_INDEX_HIT,
get_context ? &get_context->get_context_stats_.num_cache_index_miss
: nullptr,
get_context ? &get_context->get_context_stats_.num_cache_index_hit
: nullptr,
statistics, get_context);
if (cache_handle == nullptr && no_io) {
if (input_iter != nullptr) {
input_iter->Invalidate(Status::Incomplete("no blocking io"));
return input_iter;
} else {
return NewErrorInternalIterator<BlockHandle>(
Status::Incomplete("no blocking io"));
}
}
IndexReader* index_reader = nullptr;
if (cache_handle != nullptr) {
PERF_COUNTER_ADD(block_cache_index_hit_count, 1);
index_reader =
reinterpret_cast<IndexReader*>(block_cache->Value(cache_handle));
} else {
// Create index reader and put it in the cache.
Status s;
TEST_SYNC_POINT("BlockBasedTable::NewIndexIterator::thread2:2");
s = CreateIndexReader(nullptr /* prefetch_buffer */, &index_reader);
TEST_SYNC_POINT("BlockBasedTable::NewIndexIterator::thread1:1");
TEST_SYNC_POINT("BlockBasedTable::NewIndexIterator::thread2:3");
TEST_SYNC_POINT("BlockBasedTable::NewIndexIterator::thread1:4");
size_t charge = 0;
if (s.ok()) {
assert(index_reader != nullptr);
charge = index_reader->ApproximateMemoryUsage();
s = block_cache->Insert(
key, index_reader, charge, &DeleteCachedIndexEntry, &cache_handle,
rep_->table_options.cache_index_and_filter_blocks_with_high_priority
? Cache::Priority::HIGH
: Cache::Priority::LOW);
}
if (s.ok()) {
if (get_context != nullptr) {
get_context->get_context_stats_.num_cache_add++;
get_context->get_context_stats_.num_cache_bytes_write += charge;
} else {
RecordTick(statistics, BLOCK_CACHE_ADD);
RecordTick(statistics, BLOCK_CACHE_BYTES_WRITE, charge);
}
PERF_COUNTER_ADD(index_block_read_count, 1);
RecordTick(statistics, BLOCK_CACHE_INDEX_ADD);
RecordTick(statistics, BLOCK_CACHE_INDEX_BYTES_INSERT, charge);
} else {
if (index_reader != nullptr) {
delete index_reader;
}
RecordTick(statistics, BLOCK_CACHE_ADD_FAILURES);
// make sure if something goes wrong, index_reader shall remain intact.
if (input_iter != nullptr) {
input_iter->Invalidate(s);
return input_iter;
} else {
return NewErrorInternalIterator<BlockHandle>(s);
}
}
}
assert(cache_handle);
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
auto* iter = index_reader->NewIterator(
input_iter, read_options.total_order_seek || disable_prefix_seek);
// the caller would like to take ownership of the index block
// don't call RegisterCleanup() in this case, the caller will take care of it
if (index_entry != nullptr) {
*index_entry = {index_reader, block_cache, cache_handle,
false /* own_value */};
} else {
iter->RegisterCleanup(&ReleaseCachedEntry, block_cache, cache_handle);
}
return iter;
}
// 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(
Rep* rep, const ReadOptions& ro, const BlockHandle& handle,
TBlockIter* input_iter, bool is_index, bool key_includes_seq,
bool index_key_is_full, GetContext* get_context, Status s,
FilePrefetchBuffer* prefetch_buffer) {
PERF_TIMER_GUARD(new_table_block_iter_nanos);
Cache* block_cache = rep->table_options.block_cache.get();
CachableEntry<Block> block;
TBlockIter* iter;
{
const bool no_io = (ro.read_tier == kBlockCacheTier);
auto uncompression_dict_storage =
GetUncompressionDict(rep, prefetch_buffer, no_io, get_context);
const UncompressionDict& uncompression_dict =
uncompression_dict_storage.GetValue() == nullptr
? UncompressionDict::GetEmptyDict()
: *uncompression_dict_storage.GetValue();
if (s.ok()) {
s = MaybeReadBlockAndLoadToCache(prefetch_buffer, rep, ro, handle,
uncompression_dict, &block, is_index,
get_context);
}
if (input_iter != nullptr) {
iter = input_iter;
} else {
iter = new TBlockIter;
}
// Didn't get any data from block caches.
if (s.ok() && block.GetValue() == nullptr) {
if (no_io) {
// Could not read from block_cache and can't do IO
iter->Invalidate(Status::Incomplete("no blocking io"));
return iter;
}
std::unique_ptr<Block> block_value;
{
StopWatch sw(rep->ioptions.env, rep->ioptions.statistics,
READ_BLOCK_GET_MICROS);
s = ReadBlockFromFile(
rep->file.get(), prefetch_buffer, rep->footer, ro, handle,
&block_value, rep->ioptions,
rep->blocks_maybe_compressed /*do_decompress*/,
rep->blocks_maybe_compressed, uncompression_dict,
rep->persistent_cache_options,
is_index ? kDisableGlobalSequenceNumber : rep->global_seqno,
rep->table_options.read_amp_bytes_per_bit,
GetMemoryAllocator(rep->table_options));
}
if (s.ok()) {
block.SetOwnedValue(block_value.release());
}
}
// TODO(ajkr): also pin compression dictionary block when
// `pin_l0_filter_and_index_blocks_in_cache == true`.
}
if (s.ok()) {
assert(block.GetValue() != nullptr);
const bool kTotalOrderSeek = true;
// 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.
bool block_contents_pinned =
(block.IsCached() ||
(!block.GetValue()->own_bytes() && rep->immortal_table));
iter = block.GetValue()->NewIterator<TBlockIter>(
&rep->internal_comparator, rep->internal_comparator.user_comparator(),
iter, rep->ioptions.statistics, kTotalOrderSeek, key_includes_seq,
index_key_is_full, 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::Handle* cache_handle;
// 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));
Slice unique_key =
Slice(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()) {
if (cache_handle != nullptr) {
iter->RegisterCleanup(&ForceReleaseCachedEntry, block_cache,
cache_handle);
}
}
}
}
block.TransferTo(iter);
} else {
assert(block.GetValue() == nullptr);
iter->Invalidate(s);
}
return iter;
}
Status BlockBasedTable::MaybeReadBlockAndLoadToCache(
FilePrefetchBuffer* prefetch_buffer, Rep* rep, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<Block>* block_entry, bool is_index, GetContext* get_context) {
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 */;
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);
}
s = GetDataBlockFromCache(key, ckey, block_cache, block_cache_compressed,
rep, ro, block_entry, uncompression_dict,
rep->table_options.read_amp_bytes_per_bit,
is_index, get_context);
// 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;
bool do_decompress =
block_cache_compressed == nullptr && rep->blocks_maybe_compressed;
CompressionType raw_block_comp_type;
BlockContents raw_block_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_decompress /* do uncompress */, rep->blocks_maybe_compressed,
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();
}
if (s.ok()) {
SequenceNumber seq_no = rep->get_global_seqno(is_index);
// 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, ro, rep->ioptions,
block_entry, &raw_block_contents, raw_block_comp_type,
rep->table_options.format_version, uncompression_dict, seq_no,
rep->table_options.read_amp_bytes_per_bit,
GetMemoryAllocator(rep->table_options), is_index,
is_index && rep->table_options
.cache_index_and_filter_blocks_with_high_priority
? Cache::Priority::HIGH
: Cache::Priority::LOW,
get_context);
}
}
}
assert(s.ok() || block_entry->GetValue() == nullptr);
return s;
}
BlockBasedTable::PartitionedIndexIteratorState::PartitionedIndexIteratorState(
BlockBasedTable* table,
std::unordered_map<uint64_t, CachableEntry<Block>>* block_map,
bool index_key_includes_seq, bool index_key_is_full)
: table_(table),
block_map_(block_map),
index_key_includes_seq_(index_key_includes_seq),
index_key_is_full_(index_key_is_full) {}
InternalIteratorBase<BlockHandle>*
BlockBasedTable::PartitionedIndexIteratorState::NewSecondaryIterator(
const BlockHandle& handle) {
// Return a block iterator on the index partition
auto rep = table_->get_rep();
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()) {
PERF_COUNTER_ADD(block_cache_hit_count, 1);
RecordTick(rep->ioptions.statistics, BLOCK_CACHE_INDEX_HIT);
RecordTick(rep->ioptions.statistics, BLOCK_CACHE_HIT);
Cache* block_cache = rep->table_options.block_cache.get();
assert(block_cache);
RecordTick(rep->ioptions.statistics, BLOCK_CACHE_BYTES_READ,
block_cache->GetUsage(block->second.GetCacheHandle()));
Statistics* kNullStats = nullptr;
// We don't return pinned datat from index blocks, so no need
// to set `block_contents_pinned`.
return block->second.GetValue()->NewIterator<IndexBlockIter>(
&rep->internal_comparator, rep->internal_comparator.user_comparator(),
nullptr, kNullStats, true, index_key_includes_seq_, index_key_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) {
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
auto filter_entry = GetFilter(prefix_extractor);
FilterBlockReader* filter = filter_entry.GetValue();
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);
} 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<BlockHandle>> iiter(
NewIndexIterator(no_io_read_options,
/* need_upper_bound_check */ false));
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_->table_properties &&
rep_->table_properties->index_key_is_user_key
? iiter->key()
: ExtractUserKey(iiter->key()))
.starts_with(ExtractUserKey(internal_prefix))) {
// we need to check for this subtle case because our only
// guarantee is that "the key is a string >= last key in that data
// block" according to the doc/table_format.txt spec.
//
// Suppose iiter->key() starts with the desired prefix; it is not
// necessarily the case that the corresponding data block will
// contain the prefix, since iiter->key() need not be in the
// block. However, the next data block may contain the prefix, so
// we return true to play it safe.
may_match = true;
} else if (filter->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();
may_match =
filter->PrefixMayMatch(prefix, prefix_extractor, handle.offset());
}
}
}
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) {
is_out_of_bound_ = false;
if (!CheckPrefixMayMatch(target)) {
ResetDataIter();
return;
}
bool need_seek_index = true;
if (block_iter_points_to_real_block_ && block_iter_.Valid()) {
// Reseek.
prev_index_value_ = index_iter_->value();
// 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) {
index_iter_->Seek(target);
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
InitDataBlock();
}
block_iter_.Seek(target);
FindKeyForward();
CheckOutOfBound();
assert(
!block_iter_.Valid() ||
(key_includes_seq_ && icomp_.Compare(target, block_iter_.key()) <= 0) ||
(!key_includes_seq_ && user_comparator_.Compare(ExtractUserKey(target),
block_iter_.key()) <= 0));
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekForPrev(
const Slice& target) {
is_out_of_bound_ = 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()) {
index_iter_->SeekToLast();
if (!index_iter_->Valid()) {
ResetDataIter();
block_iter_points_to_real_block_ = false;
return;
}
}
InitDataBlock();
block_iter_.SeekForPrev(target);
FindKeyBackward();
assert(!block_iter_.Valid() ||
icomp_.Compare(target, block_iter_.key()) >= 0);
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekToFirst() {
is_out_of_bound_ = false;
SavePrevIndexValue();
index_iter_->SeekToFirst();
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
InitDataBlock();
block_iter_.SeekToFirst();
FindKeyForward();
CheckOutOfBound();
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekToLast() {
is_out_of_bound_ = false;
SavePrevIndexValue();
index_iter_->SeekToLast();
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
InitDataBlock();
block_iter_.SeekToLast();
FindKeyBackward();
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::Next() {
assert(block_iter_points_to_real_block_);
block_iter_.Next();
FindKeyForward();
}
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() {
assert(block_iter_points_to_real_block_);
block_iter_.Prev();
FindKeyBackward();
}
// Found that 256 KB readahead size provides the best performance, based on
// experiments, for auto readahead. Experiment data is in PR #3282.
template <class TBlockIter, typename TValue>
const size_t
BlockBasedTableIterator<TBlockIter, TValue>::kMaxAutoReadaheadSize =
256 * 1024;
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::InitDataBlock() {
BlockHandle data_block_handle = index_iter_->value();
if (!block_iter_points_to_real_block_ ||
data_block_handle.offset() != prev_index_value_.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 (!for_compaction_) {
if (read_options_.readahead_size == 0) {
// Implicit auto readahead
num_file_reads_++;
if (num_file_reads_ > 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(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(), kInitAutoReadaheadSize,
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));
}
}
Status s;
BlockBasedTable::NewDataBlockIterator<TBlockIter>(
rep, read_options_, data_block_handle, &block_iter_, is_index_,
key_includes_seq_, index_key_is_full_,
/* get_context */ nullptr, s, prefetch_buffer_.get());
block_iter_points_to_real_block_ = true;
if (read_options_.iterate_upper_bound != nullptr) {
data_block_within_upper_bound_ =
(user_comparator_.Compare(*read_options_.iterate_upper_bound,
index_iter_->user_key()) > 0);
}
}
}
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.
bool next_block_is_out_of_bound =
read_options_.iterate_upper_bound != nullptr &&
block_iter_points_to_real_block_ && !data_block_within_upper_bound_;
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()) {
InitDataBlock();
block_iter_.SeekToFirst();
} else {
return;
}
} while (!block_iter_.Valid());
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::FindKeyForward() {
assert(!is_out_of_bound_);
if (!block_iter_.Valid()) {
FindBlockForward();
}
}
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 &&
block_iter_points_to_real_block_ && block_iter_.Valid()) {
is_out_of_bound_ = user_comparator_.Compare(
*read_options_.iterate_upper_bound, user_key()) <= 0;
}
}
InternalIterator* BlockBasedTable::NewIterator(
const ReadOptions& read_options, const SliceTransform* prefix_extractor,
Arena* arena, bool skip_filters, bool for_compaction) {
bool need_upper_bound_check =
PrefixExtractorChanged(rep_->table_properties.get(), prefix_extractor);
const bool kIsNotIndex = false;
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),
!skip_filters && !read_options.total_order_seek &&
prefix_extractor != nullptr,
need_upper_bound_check, prefix_extractor, kIsNotIndex,
true /*key_includes_seq*/, true /*index_key_is_full*/, for_compaction);
} 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),
!skip_filters && !read_options.total_order_seek &&
prefix_extractor != nullptr,
need_upper_bound_check, prefix_extractor, kIsNotIndex,
true /*key_includes_seq*/, true /*index_key_is_full*/, for_compaction);
}
}
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) 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 (filter->whole_key_filtering()) {
may_match = filter->KeyMayMatch(user_key, prefix_extractor, kNotValid,
no_io, const_ikey_ptr);
} 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, false,
const_ikey_ptr)) {
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) const {
if (filter == nullptr || filter->IsBlockBased()) {
return;
}
if (filter->whole_key_filtering()) {
filter->KeysMayMatch(range, prefix_extractor, kNotValid, no_io);
} else if (!read_options.total_order_seek && prefix_extractor &&
rep_->table_properties->prefix_extractor_name.compare(
prefix_extractor->Name()) == 0) {
for (auto iter = range->begin(); iter != range->end(); ++iter) {
Slice user_key = iter->lkey->user_key();
if (!prefix_extractor->InDomain(user_key)) {
range->SkipKey(iter);
}
}
filter->PrefixesMayMatch(range, prefix_extractor, kNotValid, false);
}
}
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
Status s;
const bool no_io = read_options.read_tier == kBlockCacheTier;
CachableEntry<FilterBlockReader> filter_entry;
bool may_match;
FilterBlockReader* filter = nullptr;
{
if (!skip_filters) {
filter_entry =
GetFilter(prefix_extractor, /*prefetch_buffer*/ nullptr,
read_options.read_tier == kBlockCacheTier, get_context);
}
filter = filter_entry.GetValue();
// First check the full filter
// If full filter not useful, Then go into each block
may_match = FullFilterKeyMayMatch(read_options, filter, key, no_io,
prefix_extractor);
}
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,
/* index_entry */ nullptr, get_context);
std::unique_ptr<InternalIteratorBase<BlockHandle>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr.reset(iiter);
}
bool matched = false; // if such user key mathced a key in SST
bool done = false;
for (iiter->Seek(key); iiter->Valid() && !done; iiter->Next()) {
BlockHandle handle = iiter->value();
bool not_exist_in_filter =
filter != nullptr && filter->IsBlockBased() == true &&
!filter->KeyMayMatch(ExtractUserKey(key), prefix_extractor,
handle.offset(), no_io);
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;
} else {
DataBlockIter biter;
NewDataBlockIterator<DataBlockIter>(
rep_, read_options, iiter->value(), &biter, false,
true /* key_includes_seq */, true /* index_key_is_full */,
get_context);
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;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (!get_context->SaveValue(
parsed_key, biter.value(), &matched,
biter.IsValuePinned() ? &biter : nullptr)) {
done = true;
break;
}
}
s = biter.status();
}
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) {
const bool no_io = read_options.read_tier == kBlockCacheTier;
CachableEntry<FilterBlockReader> filter_entry;
FilterBlockReader* filter = nullptr;
MultiGetRange sst_file_range(*mget_range, mget_range->begin(),
mget_range->end());
{
if (!skip_filters) {
// TODO: Figure out where the stats should go
filter_entry = GetFilter(prefix_extractor, /*prefetch_buffer*/ nullptr,
read_options.read_tier == kBlockCacheTier,
nullptr /*get_context*/);
}
filter = filter_entry.GetValue();
// First check the full filter
// If full filter not useful, Then go into each block
FullFilterKeysMayMatch(read_options, filter, &sst_file_range, no_io,
prefix_extractor);
}
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,
/* index_entry */ nullptr, sst_file_range.begin()->get_context);
std::unique_ptr<InternalIteratorBase<BlockHandle>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr.reset(iiter);
}
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;
for (iiter->Seek(key); iiter->Valid() && !done; iiter->Next()) {
DataBlockIter biter;
NewDataBlockIterator<DataBlockIter>(
rep_, read_options, iiter->value(), &biter, false,
true /* key_includes_seq */, get_context);
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;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (!get_context->SaveValue(
parsed_key, biter.value(), &matched,
biter.IsValuePinned() ? &biter : nullptr)) {
done = true;
break;
}
}
s = biter.status();
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();
}
*(miter->s) = s;
}
}
}
Status BlockBasedTable::Prefetch(const Slice* const begin,
const Slice* const end) {
auto& comparator = rep_->internal_comparator;
auto user_comparator = comparator.user_comparator();
// pre-condition
if (begin && end && comparator.Compare(*begin, *end) > 0) {
return Status::InvalidArgument(*begin, *end);
}
IndexBlockIter iiter_on_stack;
auto iiter = NewIndexIterator(ReadOptions(), false, &iiter_on_stack);
std::unique_ptr<InternalIteratorBase<BlockHandle>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr =
std::unique_ptr<InternalIteratorBase<BlockHandle>>(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();
const bool is_user_key = rep_->table_properties &&
rep_->table_properties->index_key_is_user_key > 0;
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>(rep_, ReadOptions(), block_handle,
&biter);
if (!biter.status().ok()) {
// there was an unexpected error while pre-fetching
return biter.status();
}
}
return Status::OK();
}
Status BlockBasedTable::VerifyChecksum() {
Status s;
// Check Meta blocks
std::unique_ptr<Block> meta;
std::unique_ptr<InternalIterator> meta_iter;
s = ReadMetaBlock(rep_, 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;
InternalIteratorBase<BlockHandle>* iiter =
NewIndexIterator(ReadOptions(), false, &iiter_on_stack);
std::unique_ptr<InternalIteratorBase<BlockHandle>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr =
std::unique_ptr<InternalIteratorBase<BlockHandle>>(iiter);
}
if (!iiter->status().ok()) {
// error opening index iterator
return iiter->status();
}
s = VerifyChecksumInBlocks(iiter);
return s;
}
Status BlockBasedTable::VerifyChecksumInBlocks(
InternalIteratorBase<BlockHandle>* index_iter) {
Status s;
for (index_iter->SeekToFirst(); index_iter->Valid(); index_iter->Next()) {
s = index_iter->status();
if (!s.ok()) {
break;
}
BlockHandle handle = index_iter->value();
BlockContents contents;
BlockFetcher block_fetcher(
rep_->file.get(), nullptr /* prefetch buffer */, rep_->footer,
ReadOptions(), handle, &contents, rep_->ioptions,
false /* decompress */, false /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options);
s = block_fetcher.ReadBlockContents();
if (!s.ok()) {
break;
}
}
return s;
}
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;
BlockFetcher block_fetcher(
rep_->file.get(), nullptr /* prefetch buffer */, rep_->footer,
ReadOptions(), handle, &contents, rep_->ioptions,
false /* decompress */, false /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options);
s = block_fetcher.ReadBlockContents();
if (s.IsCorruption() && index_iter->key() == kPropertiesBlock) {
TableProperties* table_properties;
s = TryReadPropertiesWithGlobalSeqno(rep_, nullptr /* prefetch_buffer */,
index_iter->value(),
&table_properties);
delete table_properties;
}
if (!s.ok()) {
break;
}
}
return s;
}
bool BlockBasedTable::TEST_KeyInCache(const ReadOptions& options,
const Slice& key) {
std::unique_ptr<InternalIteratorBase<BlockHandle>> iiter(
NewIndexIterator(options));
iiter->Seek(key);
assert(iiter->Valid());
CachableEntry<Block> block;
BlockHandle handle = iiter->value();
Cache* block_cache = rep_->table_options.block_cache.get();
assert(block_cache != nullptr);
char cache_key_storage[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
Slice cache_key =
GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size, handle,
cache_key_storage);
Slice ckey;
Status s;
if (!rep_->compression_dict_handle.IsNull()) {
std::unique_ptr<const BlockContents> compression_dict_block;
s = ReadCompressionDictBlock(rep_, nullptr /* prefetch_buffer */,
&compression_dict_block);
if (s.ok()) {
assert(compression_dict_block != nullptr);
UncompressionDict uncompression_dict(
compression_dict_block->data.ToString(),
rep_->blocks_definitely_zstd_compressed);
s = GetDataBlockFromCache(cache_key, ckey, block_cache, nullptr, rep_,
options, &block, uncompression_dict,
0 /* read_amp_bytes_per_bit */);
}
} else {
s = GetDataBlockFromCache(
cache_key, ckey, block_cache, nullptr, rep_, options, &block,
UncompressionDict::GetEmptyDict(), 0 /* read_amp_bytes_per_bit */);
}
assert(s.ok());
return block.IsCached();
}
BlockBasedTableOptions::IndexType BlockBasedTable::UpdateIndexType() {
// Some old version of block-based tables don't have index type present in
// table properties. If that's the case we can safely use the kBinarySearch.
BlockBasedTableOptions::IndexType index_type_on_file =
BlockBasedTableOptions::kBinarySearch;
if (rep_->table_properties) {
auto& props = rep_->table_properties->user_collected_properties;
auto pos = props.find(BlockBasedTablePropertyNames::kIndexType);
if (pos != props.end()) {
index_type_on_file = static_cast<BlockBasedTableOptions::IndexType>(
DecodeFixed32(pos->second.c_str()));
// update index_type with the true type
rep_->index_type = index_type_on_file;
}
}
return index_type_on_file;
}
// 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, IndexReader** index_reader,
InternalIterator* preloaded_meta_index_iter, int level) {
auto index_type_on_file = rep_->index_type;
auto file = rep_->file.get();
const InternalKeyComparator* icomparator = &rep_->internal_comparator;
const Footer& footer = rep_->footer;
// 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 (index_type_on_file) {
case BlockBasedTableOptions::kTwoLevelIndexSearch: {
return PartitionIndexReader::Create(
this, file, prefetch_buffer, footer, footer.index_handle(),
rep_->ioptions, icomparator, index_reader,
rep_->persistent_cache_options, level,
rep_->table_properties == nullptr ||
rep_->table_properties->index_key_is_user_key == 0,
rep_->table_properties == nullptr ||
rep_->table_properties->index_value_is_delta_encoded == 0,
GetMemoryAllocator(rep_->table_options));
}
case BlockBasedTableOptions::kBinarySearch: {
return BinarySearchIndexReader::Create(
file, prefetch_buffer, footer, footer.index_handle(), rep_->ioptions,
icomparator, index_reader, rep_->persistent_cache_options,
rep_->table_properties == nullptr ||
rep_->table_properties->index_key_is_user_key == 0,
rep_->table_properties == nullptr ||
rep_->table_properties->index_value_is_delta_encoded == 0,
GetMemoryAllocator(rep_->table_options));
}
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(rep_, 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(
file, prefetch_buffer, footer, footer.index_handle(),
rep_->ioptions, icomparator, index_reader,
rep_->persistent_cache_options,
rep_->table_properties == nullptr ||
rep_->table_properties->index_key_is_user_key == 0,
rep_->table_properties == nullptr ||
rep_->table_properties->index_value_is_delta_encoded == 0,
GetMemoryAllocator(rep_->table_options));
}
meta_index_iter = meta_iter_guard.get();
}
return HashIndexReader::Create(
rep_->internal_prefix_transform.get(), footer, file, prefetch_buffer,
rep_->ioptions, icomparator, footer.index_handle(), meta_index_iter,
index_reader, rep_->hash_index_allow_collision,
rep_->persistent_cache_options,
rep_->table_properties == nullptr ||
rep_->table_properties->index_key_is_user_key == 0,
rep_->table_properties == nullptr ||
rep_->table_properties->index_value_is_delta_encoded == 0,
GetMemoryAllocator(rep_->table_options));
}
default: {
std::string error_message =
"Unrecognized index type: " + ToString(index_type_on_file);
return Status::InvalidArgument(error_message.c_str());
}
}
}
uint64_t BlockBasedTable::ApproximateOffsetOf(const Slice& key) {
std::unique_ptr<InternalIteratorBase<BlockHandle>> index_iter(
NewIndexIterator(ReadOptions()));
index_iter->Seek(key);
uint64_t result;
if (index_iter->Valid()) {
BlockHandle handle = index_iter->value();
result = handle.offset();
} else {
// key 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).
result = 0;
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;
}
bool BlockBasedTable::TEST_filter_block_preloaded() const {
return rep_->filter != nullptr;
}
bool BlockBasedTable::TEST_index_reader_preloaded() const {
return rep_->index_reader != nullptr;
}
Status BlockBasedTable::GetKVPairsFromDataBlocks(
std::vector<KVPairBlock>* kv_pair_blocks) {
std::unique_ptr<InternalIteratorBase<BlockHandle>> blockhandles_iter(
NewIndexIterator(ReadOptions()));
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>(
rep_, ReadOptions(), blockhandles_iter->value()));
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,
const SliceTransform* prefix_extractor) {
// 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(rep_, 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");
// Output Filter blocks
if (!rep_->filter && !table_properties->filter_policy_name.empty()) {
// Support only BloomFilter as off now
rocksdb::BlockBasedTableOptions table_options;
table_options.filter_policy.reset(rocksdb::NewBloomFilterPolicy(1));
if (table_properties->filter_policy_name.compare(
table_options.filter_policy->Name()) == 0) {
std::string filter_block_key = kFilterBlockPrefix;
filter_block_key.append(table_properties->filter_policy_name);
BlockHandle handle;
if (FindMetaBlock(meta_iter.get(), filter_block_key, &handle).ok()) {
BlockContents block;
BlockFetcher block_fetcher(
rep_->file.get(), nullptr /* prefetch_buffer */, rep_->footer,
ReadOptions(), handle, &block, rep_->ioptions,
false /*decompress*/, false /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(),
rep_->persistent_cache_options);
s = block_fetcher.ReadBlockContents();
if (!s.ok()) {
rep_->filter.reset(new BlockBasedFilterBlockReader(
prefix_extractor, table_options,
table_options.whole_key_filtering, std::move(block),
rep_->ioptions.statistics));
}
}
}
}
}
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_->compression_dict_handle.IsNull()) {
std::unique_ptr<const BlockContents> compression_dict_block;
s = ReadCompressionDictBlock(rep_, nullptr /* prefetch_buffer */,
&compression_dict_block);
if (!s.ok()) {
return s;
}
assert(compression_dict_block != nullptr);
auto compression_dict = compression_dict_block->data;
out_file->Append(
"Compression Dictionary:\n"
"--------------------------------------\n");
out_file->Append(" size (bytes): ");
out_file->Append(rocksdb::ToString(compression_dict.size()));
out_file->Append("\n\n");
out_file->Append(" HEX ");
out_file->Append(compression_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;
}
void BlockBasedTable::Close() {
if (rep_->closed) {
return;
}
Cache* const cache = rep_->table_options.block_cache.get();
// cleanup index, filter, and compression dictionary blocks
// to avoid accessing dangling pointers
if (!rep_->table_options.no_block_cache) {
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
// Get the filter block key
auto key = GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
rep_->filter_handle, cache_key);
cache->Erase(key);
// Get the index block key
key = GetCacheKeyFromOffset(rep_->cache_key_prefix,
rep_->cache_key_prefix_size,
rep_->dummy_index_reader_offset, cache_key);
cache->Erase(key);
if (!rep_->compression_dict_handle.IsNull()) {
// Get the compression dictionary block key
key = GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
rep_->compression_dict_handle, cache_key);
cache->Erase(key);
}
}
rep_->closed = true;
}
Status BlockBasedTable::DumpIndexBlock(WritableFile* out_file) {
out_file->Append(
"Index Details:\n"
"--------------------------------------\n");
std::unique_ptr<InternalIteratorBase<BlockHandle>> blockhandles_iter(
NewIndexIterator(ReadOptions()));
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_->table_properties &&
rep_->table_properties->index_key_is_user_key != 0) {
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).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<BlockHandle>> blockhandles_iter(
NewIndexIterator(ReadOptions()));
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();
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().ToString(true).c_str());
out_file->Append("\n");
out_file->Append("--------------------------------------\n");
std::unique_ptr<InternalIterator> datablock_iter;
datablock_iter.reset(NewDataBlockIterator<DataBlockIter>(
rep_, ReadOptions(), blockhandles_iter->value()));
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 {
void DeleteCachedFilterEntry(const Slice& /*key*/, void* value) {
FilterBlockReader* filter = reinterpret_cast<FilterBlockReader*>(value);
if (filter->statistics() != nullptr) {
RecordTick(filter->statistics(), BLOCK_CACHE_FILTER_BYTES_EVICT,
filter->ApproximateMemoryUsage());
}
delete filter;
}
void DeleteCachedIndexEntry(const Slice& /*key*/, void* value) {
IndexReader* index_reader = reinterpret_cast<IndexReader*>(value);
if (index_reader->statistics() != nullptr) {
RecordTick(index_reader->statistics(), BLOCK_CACHE_INDEX_BYTES_EVICT,
index_reader->ApproximateMemoryUsage());
}
delete index_reader;
}
void DeleteCachedUncompressionDictEntry(const Slice& /*key*/, void* value) {
UncompressionDict* dict = reinterpret_cast<UncompressionDict*>(value);
RecordTick(dict->statistics(), BLOCK_CACHE_COMPRESSION_DICT_BYTES_EVICT,
dict->ApproximateMemoryUsage());
delete dict;
}
} // anonymous namespace
} // namespace rocksdb
Reference in a new issue View git blame Copy permalink