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rocksdb/table/block_based/block_based_table_reader.cc
Levi Tamasi 3bde41b5a3 Move the filter readers out of the block cache (#5504) 
Summary:
Currently, when the block cache is used for the filter block, it is not
really the block itself that is stored in the cache but a FilterBlockReader
object. Since this object is not pure data (it has, for instance, pointers that
might dangle, including in one case a back pointer to the TableReader), it's not
really sharable. To avoid the issues around this, the current code erases the
cache entries when the TableReader is closed (which, BTW, is not sufficient
since a concurrent TableReader might have picked up the object in the meantime).
Instead of doing this, the patch moves the FilterBlockReader out of the cache
altogether, and decouples the filter reader object from the filter block.
In particular, instead of the TableReader owning, or caching/pinning the
FilterBlockReader (based on the customer's settings), with the change the
TableReader unconditionally owns the FilterBlockReader, which in turn
owns/caches/pins the filter block. This change also enables us to reuse the code
paths historically used for data blocks for filters as well.

Note:
Eviction statistics for filter blocks are temporarily broken. We plan to fix this in a
separate phase.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5504

Test Plan: make asan_check

Differential Revision: D16036974

Pulled By: ltamasi

fbshipit-source-id: 770f543c5fb4ed126fd1e04bfd3809cf4ff9c091
2019-07-16 13:14:58 -07:00

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/block_based/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_based/block.h"
#include "table/block_based/block_based_filter_block.h"
#include "table/block_based/block_based_table_factory.h"
#include "table/block_based/block_prefix_index.h"
#include "table/block_based/filter_block.h"
#include "table/block_based/full_filter_block.h"
#include "table/block_based/partitioned_filter_block.h"
#include "table/block_fetcher.h"
#include "table/format.h"
#include "table/get_context.h"
#include "table/internal_iterator.h"
#include "table/meta_blocks.h"
#include "table/multiget_context.h"
#include "table/persistent_cache_helper.h"
#include "table/sst_file_writer_collectors.h"
#include "table/two_level_iterator.h"
#include "monitoring/perf_context_imp.h"
#include "test_util/sync_point.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/file_reader_writer.h"
#include "util/stop_watch.h"
#include "util/string_util.h"
#include "util/xxhash.h"
namespace rocksdb {
extern const uint64_t kBlockBasedTableMagicNumber;
extern const std::string kHashIndexPrefixesBlock;
extern const std::string kHashIndexPrefixesMetadataBlock;
typedef BlockBasedTable::IndexReader IndexReader;
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, BlockType block_type,
const UncompressionDict& uncompression_dict,
const PersistentCacheOptions& cache_options, SequenceNumber global_seqno,
size_t read_amp_bytes_per_bit, MemoryAllocator* memory_allocator,
bool for_compaction = false) {
assert(result);
BlockContents contents;
BlockFetcher block_fetcher(
file, prefetch_buffer, footer, options, handle, &contents, ioptions,
do_uncompress, maybe_compressed, block_type, uncompression_dict,
cache_options, memory_allocator, nullptr, for_compaction);
Status s = block_fetcher.ReadBlockContents();
if (s.ok()) {
result->reset(new Block(std::move(contents), global_seqno,
read_amp_bytes_per_bit, ioptions.statistics));
}
return s;
}
Status ReadBlockFromFile(
RandomAccessFileReader* file, FilePrefetchBuffer* prefetch_buffer,
const Footer& footer, const ReadOptions& options, const BlockHandle& handle,
std::unique_ptr<BlockContents>* result, const ImmutableCFOptions& ioptions,
bool do_uncompress, bool maybe_compressed, BlockType block_type,
const UncompressionDict& uncompression_dict,
const PersistentCacheOptions& cache_options,
SequenceNumber /* global_seqno */, size_t /* read_amp_bytes_per_bit */,
MemoryAllocator* memory_allocator, bool for_compaction = false) {
assert(result);
result->reset(new BlockContents);
BlockFetcher block_fetcher(
file, prefetch_buffer, footer, options, handle, result->get(), ioptions,
do_uncompress, maybe_compressed, block_type, uncompression_dict,
cache_options, memory_allocator, nullptr, for_compaction);
const Status s = block_fetcher.ReadBlockContents();
if (!s.ok()) {
result->reset();
}
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 DeleteCachedUncompressionDictEntry(const Slice& key, void* value);
// Release the cached entry and decrement its ref count.
void ForceReleaseCachedEntry(void* arg, void* h) {
Cache* cache = reinterpret_cast<Cache*>(arg);
Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
cache->Release(handle, true /* force_erase */);
}
// Release the cached entry and decrement its ref count.
// Do not force erase
void ReleaseCachedEntry(void* arg, void* h) {
Cache* cache = reinterpret_cast<Cache*>(arg);
Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
cache->Release(handle, false /* force_erase */);
}
// For hash based index, return true if prefix_extractor and
// prefix_extractor_block mismatch, false otherwise. This flag will be used
// as total_order_seek via NewIndexIterator
bool PrefixExtractorChanged(const TableProperties* table_properties,
const SliceTransform* prefix_extractor) {
// BlockBasedTableOptions::kHashSearch requires prefix_extractor to be set.
// Turn off hash index in prefix_extractor is not set; if prefix_extractor
// is set but prefix_extractor_block is not set, also disable hash index
if (prefix_extractor == nullptr || table_properties == nullptr ||
table_properties->prefix_extractor_name.empty()) {
return true;
}
// prefix_extractor and prefix_extractor_block are both non-empty
if (table_properties->prefix_extractor_name.compare(
prefix_extractor->Name()) != 0) {
return true;
} else {
return false;
}
}
CacheAllocationPtr CopyBufferToHeap(MemoryAllocator* allocator, Slice& buf) {
CacheAllocationPtr heap_buf;
heap_buf = AllocateBlock(buf.size(), allocator);
memcpy(heap_buf.get(), buf.data(), buf.size());
return heap_buf;
}
} // namespace
// Encapsulates common functionality for the various index reader
// implementations. Provides access to the index block regardless of whether
// it is owned by the reader or stored in the cache, or whether it is pinned
// in the cache or not.
class BlockBasedTable::IndexReaderCommon : public BlockBasedTable::IndexReader {
public:
IndexReaderCommon(const BlockBasedTable* t,
CachableEntry<Block>&& index_block)
: table_(t), index_block_(std::move(index_block)) {
assert(table_ != nullptr);
}
protected:
static Status ReadIndexBlock(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer,
const ReadOptions& read_options,
GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block);
const BlockBasedTable* table() const { return table_; }
const InternalKeyComparator* internal_comparator() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return &table_->get_rep()->internal_comparator;
}
bool index_has_first_key() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_has_first_key;
}
bool index_key_includes_seq() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_key_includes_seq;
}
bool index_value_is_full() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_value_is_full;
}
Status GetOrReadIndexBlock(bool no_io, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) const;
size_t ApproximateIndexBlockMemoryUsage() const {
assert(!index_block_.GetOwnValue() || index_block_.GetValue() != nullptr);
return index_block_.GetOwnValue()
? index_block_.GetValue()->ApproximateMemoryUsage()
: 0;
}
private:
const BlockBasedTable* table_;
CachableEntry<Block> index_block_;
};
Status BlockBasedTable::IndexReaderCommon::ReadIndexBlock(
const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
const ReadOptions& read_options, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) {
PERF_TIMER_GUARD(read_index_block_nanos);
assert(table != nullptr);
assert(index_block != nullptr);
assert(index_block->IsEmpty());
const Rep* const rep = table->get_rep();
assert(rep != nullptr);
const Status s = table->RetrieveBlock(
prefetch_buffer, read_options, rep->footer.index_handle(),
UncompressionDict::GetEmptyDict(), index_block, BlockType::kIndex,
get_context, lookup_context);
return s;
}
Status BlockBasedTable::IndexReaderCommon::GetOrReadIndexBlock(
bool no_io, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) const {
assert(index_block != nullptr);
if (!index_block_.IsEmpty()) {
index_block->SetUnownedValue(index_block_.GetValue());
return Status::OK();
}
ReadOptions read_options;
if (no_io) {
read_options.read_tier = kBlockCacheTier;
}
return ReadIndexBlock(table_, /*prefetch_buffer=*/nullptr, read_options,
get_context, lookup_context, index_block);
}
// Index that allows binary search lookup in a two-level index structure.
class PartitionIndexReader : public BlockBasedTable::IndexReaderCommon {
public:
// Read the partition index from the file and create an instance for
// `PartitionIndexReader`.
// On success, index_reader will be populated; otherwise it will remain
// unmodified.
static Status Create(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer, bool use_cache,
bool prefetch, bool pin,
BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
assert(table != nullptr);
assert(table->get_rep());
assert(!pin || prefetch);
assert(index_reader != nullptr);
CachableEntry<Block> index_block;
if (prefetch || !use_cache) {
const Status s =
ReadIndexBlock(table, prefetch_buffer, ReadOptions(),
/*get_context=*/nullptr, lookup_context, &index_block);
if (!s.ok()) {
return s;
}
if (use_cache && !pin) {
index_block.Reset();
}
}
index_reader->reset(
new PartitionIndexReader(table, std::move(index_block)));
return Status::OK();
}
// return a two-level iterator: first level is on the partition index
InternalIteratorBase<IndexValue>* NewIterator(
const ReadOptions& read_options, bool /* disable_prefix_seek */,
IndexBlockIter* iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) override {
const bool no_io = (read_options.read_tier == kBlockCacheTier);
CachableEntry<Block> index_block;
const Status s =
GetOrReadIndexBlock(no_io, get_context, lookup_context, &index_block);
if (!s.ok()) {
if (iter != nullptr) {
iter->Invalidate(s);
return iter;
}
return NewErrorInternalIterator<IndexValue>(s);
}
InternalIteratorBase<IndexValue>* it = nullptr;
Statistics* kNullStats = nullptr;
// Filters are already checked before seeking the index
if (!partition_map_.empty()) {
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
it = NewTwoLevelIterator(
new BlockBasedTable::PartitionedIndexIteratorState(table(),
&partition_map_),
index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(),
nullptr, kNullStats, true, index_has_first_key(),
index_key_includes_seq(), index_value_is_full()));
} else {
ReadOptions ro;
ro.fill_cache = read_options.fill_cache;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
it = new BlockBasedTableIterator<IndexBlockIter, IndexValue>(
table(), ro, *internal_comparator(),
index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(),
nullptr, kNullStats, true, index_has_first_key(),
index_key_includes_seq(), index_value_is_full()),
false, true, /* prefix_extractor */ nullptr, BlockType::kIndex,
lookup_context ? lookup_context->caller
: TableReaderCaller::kUncategorized);
}
assert(it != nullptr);
index_block.TransferTo(it);
return it;
// TODO(myabandeh): Update TwoLevelIterator to be able to make use of
// on-stack BlockIter while the state is on heap. Currentlly it assumes
// the first level iter is always on heap and will attempt to delete it
// in its destructor.
}
void CacheDependencies(bool pin) override {
// Before read partitions, prefetch them to avoid lots of IOs
BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
const BlockBasedTable::Rep* rep = table()->rep_;
IndexBlockIter biter;
BlockHandle handle;
Statistics* kNullStats = nullptr;
CachableEntry<Block> index_block;
Status s = GetOrReadIndexBlock(false /* no_io */, nullptr /* get_context */,
&lookup_context, &index_block);
if (!s.ok()) {
ROCKS_LOG_WARN(rep->ioptions.info_log,
"Error retrieving top-level index block while trying to "
"cache index partitions: %s",
s.ToString().c_str());
return;
}
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(), &biter,
kNullStats, true, index_has_first_key(), index_key_includes_seq(),
index_value_is_full());
// Index partitions are assumed to be consecuitive. Prefetch them all.
// Read the first block offset
biter.SeekToFirst();
if (!biter.Valid()) {
// Empty index.
return;
}
handle = biter.value().handle;
uint64_t prefetch_off = handle.offset();
// Read the last block's offset
biter.SeekToLast();
if (!biter.Valid()) {
// Empty index.
return;
}
handle = biter.value().handle;
uint64_t last_off = handle.offset() + handle.size() + kBlockTrailerSize;
uint64_t prefetch_len = last_off - prefetch_off;
std::unique_ptr<FilePrefetchBuffer> prefetch_buffer;
auto& file = rep->file;
prefetch_buffer.reset(new FilePrefetchBuffer());
s = prefetch_buffer->Prefetch(file.get(), prefetch_off,
static_cast<size_t>(prefetch_len));
// After prefetch, read the partitions one by one
biter.SeekToFirst();
auto ro = ReadOptions();
for (; biter.Valid(); biter.Next()) {
handle = biter.value().handle;
CachableEntry<Block> block;
// TODO: Support counter batch update for partitioned index and
// filter blocks
s = table()->MaybeReadBlockAndLoadToCache(
prefetch_buffer.get(), ro, handle, UncompressionDict::GetEmptyDict(),
&block, BlockType::kIndex, /*get_context=*/nullptr, &lookup_context,
/*contents=*/nullptr);
assert(s.ok() || block.GetValue() == nullptr);
if (s.ok() && block.GetValue() != nullptr) {
if (block.IsCached()) {
if (pin) {
partition_map_[handle.offset()] = std::move(block);
}
}
}
}
}
size_t ApproximateMemoryUsage() const override {
size_t usage = ApproximateIndexBlockMemoryUsage();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size(const_cast<PartitionIndexReader*>(this));
#else
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
// TODO(myabandeh): more accurate estimate of partition_map_ mem usage
return usage;
}
private:
PartitionIndexReader(const BlockBasedTable* t,
CachableEntry<Block>&& index_block)
: IndexReaderCommon(t, std::move(index_block)) {}
std::unordered_map<uint64_t, CachableEntry<Block>> partition_map_;
};
// Index that allows binary search lookup for the first key of each block.
// This class can be viewed as a thin wrapper for `Block` class which already
// supports binary search.
class BinarySearchIndexReader : public BlockBasedTable::IndexReaderCommon {
public:
// Read index from the file and create an intance for
// `BinarySearchIndexReader`.
// On success, index_reader will be populated; otherwise it will remain
// unmodified.
static Status Create(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer, bool use_cache,
bool prefetch, bool pin,
BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
assert(table != nullptr);
assert(table->get_rep());
assert(!pin || prefetch);
assert(index_reader != nullptr);
CachableEntry<Block> index_block;
if (prefetch || !use_cache) {
const Status s =
ReadIndexBlock(table, prefetch_buffer, ReadOptions(),
/*get_context=*/nullptr, lookup_context, &index_block);
if (!s.ok()) {
return s;
}
if (use_cache && !pin) {
index_block.Reset();
}
}
index_reader->reset(
new BinarySearchIndexReader(table, std::move(index_block)));
return Status::OK();
}
InternalIteratorBase<IndexValue>* NewIterator(
const ReadOptions& read_options, bool /* disable_prefix_seek */,
IndexBlockIter* iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) override {
const bool no_io = (read_options.read_tier == kBlockCacheTier);
CachableEntry<Block> index_block;
const Status s =
GetOrReadIndexBlock(no_io, get_context, lookup_context, &index_block);
if (!s.ok()) {
if (iter != nullptr) {
iter->Invalidate(s);
return iter;
}
return NewErrorInternalIterator<IndexValue>(s);
}
Statistics* kNullStats = nullptr;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
auto it = index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(), iter,
kNullStats, true, index_has_first_key(), index_key_includes_seq(),
index_value_is_full());
assert(it != nullptr);
index_block.TransferTo(it);
return it;
}
size_t ApproximateMemoryUsage() const override {
size_t usage = ApproximateIndexBlockMemoryUsage();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size(const_cast<BinarySearchIndexReader*>(this));
#else
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
return usage;
}
private:
BinarySearchIndexReader(const BlockBasedTable* t,
CachableEntry<Block>&& index_block)
: IndexReaderCommon(t, std::move(index_block)) {}
};
// Index that leverages an internal hash table to quicken the lookup for a given
// key.
class HashIndexReader : public BlockBasedTable::IndexReaderCommon {
public:
static Status Create(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer,
InternalIterator* meta_index_iter, bool use_cache,
bool prefetch, bool pin,
BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
assert(table != nullptr);
assert(index_reader != nullptr);
assert(!pin || prefetch);
const BlockBasedTable::Rep* rep = table->get_rep();
assert(rep != nullptr);
CachableEntry<Block> index_block;
if (prefetch || !use_cache) {
const Status s =
ReadIndexBlock(table, prefetch_buffer, ReadOptions(),
/*get_context=*/nullptr, lookup_context, &index_block);
if (!s.ok()) {
return s;
}
if (use_cache && !pin) {
index_block.Reset();
}
}
// Note, failure to create prefix hash index does not need to be a
// hard error. We can still fall back to the original binary search index.
// So, Create will succeed regardless, from this point on.
index_reader->reset(new HashIndexReader(table, std::move(index_block)));
// Get prefixes block
BlockHandle prefixes_handle;
Status s = FindMetaBlock(meta_index_iter, kHashIndexPrefixesBlock,
&prefixes_handle);
if (!s.ok()) {
// TODO: log error
return Status::OK();
}
// Get index metadata block
BlockHandle prefixes_meta_handle;
s = FindMetaBlock(meta_index_iter, kHashIndexPrefixesMetadataBlock,
&prefixes_meta_handle);
if (!s.ok()) {
// TODO: log error
return Status::OK();
}
RandomAccessFileReader* const file = rep->file.get();
const Footer& footer = rep->footer;
const ImmutableCFOptions& ioptions = rep->ioptions;
const PersistentCacheOptions& cache_options = rep->persistent_cache_options;
MemoryAllocator* const memory_allocator =
GetMemoryAllocator(rep->table_options);
// Read contents for the blocks
BlockContents prefixes_contents;
BlockFetcher prefixes_block_fetcher(
file, prefetch_buffer, footer, ReadOptions(), prefixes_handle,
&prefixes_contents, ioptions, true /*decompress*/,
true /*maybe_compressed*/, BlockType::kHashIndexPrefixes,
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
s = prefixes_block_fetcher.ReadBlockContents();
if (!s.ok()) {
return s;
}
BlockContents prefixes_meta_contents;
BlockFetcher prefixes_meta_block_fetcher(
file, prefetch_buffer, footer, ReadOptions(), prefixes_meta_handle,
&prefixes_meta_contents, ioptions, true /*decompress*/,
true /*maybe_compressed*/, BlockType::kHashIndexMetadata,
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
s = prefixes_meta_block_fetcher.ReadBlockContents();
if (!s.ok()) {
// TODO: log error
return Status::OK();
}
BlockPrefixIndex* prefix_index = nullptr;
s = BlockPrefixIndex::Create(rep->internal_prefix_transform.get(),
prefixes_contents.data,
prefixes_meta_contents.data, &prefix_index);
// TODO: log error
if (s.ok()) {
HashIndexReader* const hash_index_reader =
static_cast<HashIndexReader*>(index_reader->get());
hash_index_reader->prefix_index_.reset(prefix_index);
}
return Status::OK();
}
InternalIteratorBase<IndexValue>* NewIterator(
const ReadOptions& read_options, bool disable_prefix_seek,
IndexBlockIter* iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) override {
const bool no_io = (read_options.read_tier == kBlockCacheTier);
CachableEntry<Block> index_block;
const Status s =
GetOrReadIndexBlock(no_io, get_context, lookup_context, &index_block);
if (!s.ok()) {
if (iter != nullptr) {
iter->Invalidate(s);
return iter;
}
return NewErrorInternalIterator<IndexValue>(s);
}
Statistics* kNullStats = nullptr;
const bool total_order_seek =
read_options.total_order_seek || disable_prefix_seek;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
auto it = index_block.GetValue()->NewIndexIterator(
internal_comparator(), internal_comparator()->user_comparator(), iter,
kNullStats, total_order_seek, index_has_first_key(),
index_key_includes_seq(), index_value_is_full(),
false /* block_contents_pinned */, prefix_index_.get());
assert(it != nullptr);
index_block.TransferTo(it);
return it;
}
size_t ApproximateMemoryUsage() const override {
size_t usage = ApproximateIndexBlockMemoryUsage();
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
usage += malloc_usable_size(const_cast<HashIndexReader*>(this));
#else
if (prefix_index_) {
usage += prefix_index_->ApproximateMemoryUsage();
}
usage += sizeof(*this);
#endif // ROCKSDB_MALLOC_USABLE_SIZE
return usage;
}
private:
HashIndexReader(const BlockBasedTable* t, CachableEntry<Block>&& index_block)
: IndexReaderCommon(t, std::move(index_block)) {}
std::unique_ptr<BlockPrefixIndex> prefix_index_;
};
void BlockBasedTable::UpdateCacheHitMetrics(BlockType block_type,
GetContext* get_context,
size_t usage) const {
Statistics* const statistics = rep_->ioptions.statistics;
PERF_COUNTER_ADD(block_cache_hit_count, 1);
PERF_COUNTER_BY_LEVEL_ADD(block_cache_hit_count, 1,
static_cast<uint32_t>(rep_->level));
if (get_context) {
++get_context->get_context_stats_.num_cache_hit;
get_context->get_context_stats_.num_cache_bytes_read += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_HIT);
RecordTick(statistics, BLOCK_CACHE_BYTES_READ, usage);
}
switch (block_type) {
case BlockType::kFilter:
PERF_COUNTER_ADD(block_cache_filter_hit_count, 1);
if (get_context) {
++get_context->get_context_stats_.num_cache_filter_hit;
} else {
RecordTick(statistics, BLOCK_CACHE_FILTER_HIT);
}
break;
case BlockType::kCompressionDictionary:
// TODO: introduce perf counter for compression dictionary hit count
if (get_context) {
++get_context->get_context_stats_.num_cache_compression_dict_hit;
} else {
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_HIT);
}
break;
case BlockType::kIndex:
PERF_COUNTER_ADD(block_cache_index_hit_count, 1);
if (get_context) {
++get_context->get_context_stats_.num_cache_index_hit;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_HIT);
}
break;
default:
// TODO: introduce dedicated tickers/statistics/counters
// for range tombstones
if (get_context) {
++get_context->get_context_stats_.num_cache_data_hit;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_HIT);
}
break;
}
}
void BlockBasedTable::UpdateCacheMissMetrics(BlockType block_type,
GetContext* get_context) const {
Statistics* const statistics = rep_->ioptions.statistics;
// TODO: introduce aggregate (not per-level) block cache miss count
PERF_COUNTER_BY_LEVEL_ADD(block_cache_miss_count, 1,
static_cast<uint32_t>(rep_->level));
if (get_context) {
++get_context->get_context_stats_.num_cache_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_MISS);
}
// TODO: introduce perf counters for misses per block type
switch (block_type) {
case BlockType::kFilter:
if (get_context) {
++get_context->get_context_stats_.num_cache_filter_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_FILTER_MISS);
}
break;
case BlockType::kCompressionDictionary:
if (get_context) {
++get_context->get_context_stats_.num_cache_compression_dict_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_MISS);
}
break;
case BlockType::kIndex:
if (get_context) {
++get_context->get_context_stats_.num_cache_index_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_MISS);
}
break;
default:
// TODO: introduce dedicated tickers/statistics/counters
// for range tombstones
if (get_context) {
++get_context->get_context_stats_.num_cache_data_miss;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_MISS);
}
break;
}
}
void BlockBasedTable::UpdateCacheInsertionMetrics(BlockType block_type,
GetContext* get_context,
size_t usage) const {
Statistics* const statistics = rep_->ioptions.statistics;
// TODO: introduce perf counters for block cache insertions
if (get_context) {
++get_context->get_context_stats_.num_cache_add;
get_context->get_context_stats_.num_cache_bytes_write += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_ADD);
RecordTick(statistics, BLOCK_CACHE_BYTES_WRITE, usage);
}
switch (block_type) {
case BlockType::kFilter:
if (get_context) {
++get_context->get_context_stats_.num_cache_filter_add;
get_context->get_context_stats_.num_cache_filter_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_FILTER_ADD);
RecordTick(statistics, BLOCK_CACHE_FILTER_BYTES_INSERT, usage);
}
break;
case BlockType::kCompressionDictionary:
if (get_context) {
++get_context->get_context_stats_.num_cache_compression_dict_add;
get_context->get_context_stats_
.num_cache_compression_dict_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_ADD);
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_BYTES_INSERT,
usage);
}
break;
case BlockType::kIndex:
if (get_context) {
++get_context->get_context_stats_.num_cache_index_add;
get_context->get_context_stats_.num_cache_index_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_ADD);
RecordTick(statistics, BLOCK_CACHE_INDEX_BYTES_INSERT, usage);
}
break;
default:
// TODO: introduce dedicated tickers/statistics/counters
// for range tombstones
if (get_context) {
++get_context->get_context_stats_.num_cache_data_add;
get_context->get_context_stats_.num_cache_data_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_ADD);
RecordTick(statistics, BLOCK_CACHE_DATA_BYTES_INSERT, usage);
}
break;
}
}
Cache::Handle* BlockBasedTable::GetEntryFromCache(
Cache* block_cache, const Slice& key, BlockType block_type,
GetContext* get_context) const {
auto cache_handle = block_cache->Lookup(key, rep_->ioptions.statistics);
if (cache_handle != nullptr) {
UpdateCacheHitMetrics(block_type, get_context,
block_cache->GetUsage(cache_handle));
} else {
UpdateCacheMissMetrics(block_type, get_context);
}
return cache_handle;
}
// Helper function to setup the cache key's prefix for the Table.
void BlockBasedTable::SetupCacheKeyPrefix(Rep* rep) {
assert(kMaxCacheKeyPrefixSize >= 10);
rep->cache_key_prefix_size = 0;
rep->compressed_cache_key_prefix_size = 0;
if (rep->table_options.block_cache != nullptr) {
GenerateCachePrefix(rep->table_options.block_cache.get(), rep->file->file(),
&rep->cache_key_prefix[0], &rep->cache_key_prefix_size);
}
if (rep->table_options.persistent_cache != nullptr) {
GenerateCachePrefix(/*cache=*/nullptr, rep->file->file(),
&rep->persistent_cache_key_prefix[0],
&rep->persistent_cache_key_prefix_size);
}
if (rep->table_options.block_cache_compressed != nullptr) {
GenerateCachePrefix(rep->table_options.block_cache_compressed.get(),
rep->file->file(), &rep->compressed_cache_key_prefix[0],
&rep->compressed_cache_key_prefix_size);
}
}
void BlockBasedTable::GenerateCachePrefix(Cache* cc, RandomAccessFile* file,
char* buffer, size_t* size) {
// generate an id from the file
*size = file->GetUniqueId(buffer, kMaxCacheKeyPrefixSize);
// If the prefix wasn't generated or was too long,
// create one from the cache.
if (cc && *size == 0) {
char* end = EncodeVarint64(buffer, cc->NewId());
*size = static_cast<size_t>(end - buffer);
}
}
void BlockBasedTable::GenerateCachePrefix(Cache* cc, WritableFile* file,
char* buffer, size_t* size) {
// generate an id from the file
*size = file->GetUniqueId(buffer, kMaxCacheKeyPrefixSize);
// If the prefix wasn't generated or was too long,
// create one from the cache.
if (*size == 0) {
char* end = EncodeVarint64(buffer, cc->NewId());
*size = static_cast<size_t>(end - buffer);
}
}
namespace {
// Return True if table_properties has `user_prop_name` has a `true` value
// or it doesn't contain this property (for backward compatible).
bool IsFeatureSupported(const TableProperties& table_properties,
const std::string& user_prop_name, Logger* info_log) {
auto& props = table_properties.user_collected_properties;
auto pos = props.find(user_prop_name);
// Older version doesn't have this value set. Skip this check.
if (pos != props.end()) {
if (pos->second == kPropFalse) {
return false;
} else if (pos->second != kPropTrue) {
ROCKS_LOG_WARN(info_log, "Property %s has invalidate value %s",
user_prop_name.c_str(), pos->second.c_str());
}
}
return true;
}
// Caller has to ensure seqno is not nullptr.
Status GetGlobalSequenceNumber(const TableProperties& table_properties,
SequenceNumber largest_seqno,
SequenceNumber* seqno) {
const auto& props = table_properties.user_collected_properties;
const auto version_pos = props.find(ExternalSstFilePropertyNames::kVersion);
const auto seqno_pos = props.find(ExternalSstFilePropertyNames::kGlobalSeqno);
*seqno = kDisableGlobalSequenceNumber;
if (version_pos == props.end()) {
if (seqno_pos != props.end()) {
std::array<char, 200> msg_buf;
// This is not an external sst file, global_seqno is not supported.
snprintf(
msg_buf.data(), msg_buf.max_size(),
"A non-external sst file have global seqno property with value %s",
seqno_pos->second.c_str());
return Status::Corruption(msg_buf.data());
}
return Status::OK();
}
uint32_t version = DecodeFixed32(version_pos->second.c_str());
if (version < 2) {
if (seqno_pos != props.end() || version != 1) {
std::array<char, 200> msg_buf;
// This is a v1 external sst file, global_seqno is not supported.
snprintf(msg_buf.data(), msg_buf.max_size(),
"An external sst file with version %u have global seqno "
"property with value %s",
version, seqno_pos->second.c_str());
return Status::Corruption(msg_buf.data());
}
return Status::OK();
}
// Since we have a plan to deprecate global_seqno, we do not return failure
// if seqno_pos == props.end(). We rely on version_pos to detect whether the
// SST is external.
SequenceNumber global_seqno(0);
if (seqno_pos != props.end()) {
global_seqno = DecodeFixed64(seqno_pos->second.c_str());
}
// SstTableReader open table reader with kMaxSequenceNumber as largest_seqno
// to denote it is unknown.
if (largest_seqno < kMaxSequenceNumber) {
if (global_seqno == 0) {
global_seqno = largest_seqno;
}
if (global_seqno != largest_seqno) {
std::array<char, 200> msg_buf;
snprintf(
msg_buf.data(), msg_buf.max_size(),
"An external sst file with version %u have global seqno property "
"with value %s, while largest seqno in the file is %llu",
version, seqno_pos->second.c_str(),
static_cast<unsigned long long>(largest_seqno));
return Status::Corruption(msg_buf.data());
}
}
*seqno = global_seqno;
if (global_seqno > kMaxSequenceNumber) {
std::array<char, 200> msg_buf;
snprintf(msg_buf.data(), msg_buf.max_size(),
"An external sst file with version %u have global seqno property "
"with value %llu, which is greater than kMaxSequenceNumber",
version, static_cast<unsigned long long>(global_seqno));
return Status::Corruption(msg_buf.data());
}
return Status::OK();
}
} // namespace
Slice BlockBasedTable::GetCacheKey(const char* cache_key_prefix,
size_t cache_key_prefix_size,
const BlockHandle& handle, char* cache_key) {
assert(cache_key != nullptr);
assert(cache_key_prefix_size != 0);
assert(cache_key_prefix_size <= kMaxCacheKeyPrefixSize);
memcpy(cache_key, cache_key_prefix, cache_key_prefix_size);
char* end =
EncodeVarint64(cache_key + cache_key_prefix_size, handle.offset());
return Slice(cache_key, static_cast<size_t>(end - cache_key));
}
Status BlockBasedTable::Open(
const ImmutableCFOptions& ioptions, const EnvOptions& env_options,
const BlockBasedTableOptions& table_options,
const InternalKeyComparator& internal_comparator,
std::unique_ptr<RandomAccessFileReader>&& file, uint64_t file_size,
std::unique_ptr<TableReader>* table_reader,
const SliceTransform* prefix_extractor,
const bool prefetch_index_and_filter_in_cache, const bool skip_filters,
const int level, const bool immortal_table,
const SequenceNumber largest_seqno, TailPrefetchStats* tail_prefetch_stats,
BlockCacheTracer* const block_cache_tracer) {
table_reader->reset();
Status s;
Footer footer;
std::unique_ptr<FilePrefetchBuffer> prefetch_buffer;
// prefetch both index and filters, down to all partitions
const bool prefetch_all = prefetch_index_and_filter_in_cache || level == 0;
const bool preload_all = !table_options.cache_index_and_filter_blocks;
s = PrefetchTail(file.get(), file_size, tail_prefetch_stats, prefetch_all,
preload_all, &prefetch_buffer);
// Read in the following order:
// 1. Footer
// 2. [metaindex block]
// 3. [meta block: properties]
// 4. [meta block: range deletion tombstone]
// 5. [meta block: compression dictionary]
// 6. [meta block: index]
// 7. [meta block: filter]
s = ReadFooterFromFile(file.get(), prefetch_buffer.get(), file_size, &footer,
kBlockBasedTableMagicNumber);
if (!s.ok()) {
return s;
}
if (!BlockBasedTableSupportedVersion(footer.version())) {
return Status::Corruption(
"Unknown Footer version. Maybe this file was created with newer "
"version of RocksDB?");
}
// We've successfully read the footer. We are ready to serve requests.
// Better not mutate rep_ after the creation. eg. internal_prefix_transform
// raw pointer will be used to create HashIndexReader, whose reset may
// access a dangling pointer.
BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
Rep* rep = new BlockBasedTable::Rep(ioptions, env_options, table_options,
internal_comparator, skip_filters, level,
immortal_table);
rep->file = std::move(file);
rep->footer = footer;
rep->hash_index_allow_collision = table_options.hash_index_allow_collision;
// We need to wrap data with internal_prefix_transform to make sure it can
// handle prefix correctly.
rep->internal_prefix_transform.reset(
new InternalKeySliceTransform(prefix_extractor));
SetupCacheKeyPrefix(rep);
std::unique_ptr<BlockBasedTable> new_table(
new BlockBasedTable(rep, block_cache_tracer));
// page cache options
rep->persistent_cache_options =
PersistentCacheOptions(rep->table_options.persistent_cache,
std::string(rep->persistent_cache_key_prefix,
rep->persistent_cache_key_prefix_size),
rep->ioptions.statistics);
// Meta-blocks are not dictionary compressed. Explicitly set the dictionary
// handle to null, otherwise it may be seen as uninitialized during the below
// meta-block reads.
rep->compression_dict_handle = BlockHandle::NullBlockHandle();
// Read metaindex
std::unique_ptr<Block> meta;
std::unique_ptr<InternalIterator> meta_iter;
s = new_table->ReadMetaBlock(prefetch_buffer.get(), &meta, &meta_iter);
if (!s.ok()) {
return s;
}
// Populates table_properties and some fields that depend on it,
// such as index_type.
s = new_table->ReadPropertiesBlock(prefetch_buffer.get(), meta_iter.get(),
largest_seqno);
if (!s.ok()) {
return s;
}
s = new_table->ReadRangeDelBlock(prefetch_buffer.get(), meta_iter.get(),
internal_comparator, &lookup_context);
if (!s.ok()) {
return s;
}
s = new_table->PrefetchIndexAndFilterBlocks(
prefetch_buffer.get(), meta_iter.get(), new_table.get(), prefetch_all,
table_options, level, &lookup_context);
if (s.ok()) {
// Update tail prefetch stats
assert(prefetch_buffer.get() != nullptr);
if (tail_prefetch_stats != nullptr) {
assert(prefetch_buffer->min_offset_read() < file_size);
tail_prefetch_stats->RecordEffectiveSize(
static_cast<size_t>(file_size) - prefetch_buffer->min_offset_read());
}
*table_reader = std::move(new_table);
}
return s;
}
Status BlockBasedTable::PrefetchTail(
RandomAccessFileReader* file, uint64_t file_size,
TailPrefetchStats* tail_prefetch_stats, const bool prefetch_all,
const bool preload_all,
std::unique_ptr<FilePrefetchBuffer>* prefetch_buffer) {
size_t tail_prefetch_size = 0;
if (tail_prefetch_stats != nullptr) {
// Multiple threads may get a 0 (no history) when running in parallel,
// but it will get cleared after the first of them finishes.
tail_prefetch_size = tail_prefetch_stats->GetSuggestedPrefetchSize();
}
if (tail_prefetch_size == 0) {
// Before read footer, readahead backwards to prefetch data. Do more
// readahead if we're going to read index/filter.
// TODO: This may incorrectly select small readahead in case partitioned
// index/filter is enabled and top-level partition pinning is enabled.
// That's because we need to issue readahead before we read the properties,
// at which point we don't yet know the index type.
tail_prefetch_size = prefetch_all || preload_all ? 512 * 1024 : 4 * 1024;
}
size_t prefetch_off;
size_t prefetch_len;
if (file_size < tail_prefetch_size) {
prefetch_off = 0;
prefetch_len = static_cast<size_t>(file_size);
} else {
prefetch_off = static_cast<size_t>(file_size - tail_prefetch_size);
prefetch_len = tail_prefetch_size;
}
TEST_SYNC_POINT_CALLBACK("BlockBasedTable::Open::TailPrefetchLen",
&tail_prefetch_size);
Status s;
// TODO should not have this special logic in the future.
if (!file->use_direct_io()) {
prefetch_buffer->reset(new FilePrefetchBuffer(nullptr, 0, 0, false, true));
s = file->Prefetch(prefetch_off, prefetch_len);
} else {
prefetch_buffer->reset(new FilePrefetchBuffer(nullptr, 0, 0, true, true));
s = (*prefetch_buffer)->Prefetch(file, prefetch_off, prefetch_len);
}
return s;
}
Status VerifyChecksum(const ChecksumType type, const char* buf, size_t len,
uint32_t expected) {
Status s;
uint32_t actual = 0;
switch (type) {
case kNoChecksum:
break;
case kCRC32c:
expected = crc32c::Unmask(expected);
actual = crc32c::Value(buf, len);
break;
case kxxHash:
actual = XXH32(buf, static_cast<int>(len), 0);
break;
case kxxHash64:
actual = static_cast<uint32_t>(XXH64(buf, static_cast<int>(len), 0) &
uint64_t{0xffffffff});
break;
default:
s = Status::Corruption("unknown checksum type");
}
if (s.ok() && actual != expected) {
s = Status::Corruption("properties block checksum mismatched");
}
return s;
}
Status BlockBasedTable::TryReadPropertiesWithGlobalSeqno(
FilePrefetchBuffer* prefetch_buffer, const Slice& handle_value,
TableProperties** table_properties) {
assert(table_properties != nullptr);
// If this is an external SST file ingested with write_global_seqno set to
// true, then we expect the checksum mismatch because checksum was written
// by SstFileWriter, but its global seqno in the properties block may have
// been changed during ingestion. In this case, we read the properties
// block, copy it to a memory buffer, change the global seqno to its
// original value, i.e. 0, and verify the checksum again.
BlockHandle props_block_handle;
CacheAllocationPtr tmp_buf;
Status s = ReadProperties(handle_value, rep_->file.get(), prefetch_buffer,
rep_->footer, rep_->ioptions, table_properties,
false /* verify_checksum */, &props_block_handle,
&tmp_buf, false /* compression_type_missing */,
nullptr /* memory_allocator */);
if (s.ok() && tmp_buf) {
const auto seqno_pos_iter =
(*table_properties)
->properties_offsets.find(
ExternalSstFilePropertyNames::kGlobalSeqno);
size_t block_size = static_cast<size_t>(props_block_handle.size());
if (seqno_pos_iter != (*table_properties)->properties_offsets.end()) {
uint64_t global_seqno_offset = seqno_pos_iter->second;
EncodeFixed64(
tmp_buf.get() + global_seqno_offset - props_block_handle.offset(), 0);
}
uint32_t value = DecodeFixed32(tmp_buf.get() + block_size + 1);
s = rocksdb::VerifyChecksum(rep_->footer.checksum(), tmp_buf.get(),
block_size + 1, value);
}
return s;
}
Status BlockBasedTable::ReadPropertiesBlock(
FilePrefetchBuffer* prefetch_buffer, InternalIterator* meta_iter,
const SequenceNumber largest_seqno) {
bool found_properties_block = true;
Status s;
s = SeekToPropertiesBlock(meta_iter, &found_properties_block);
if (!s.ok()) {
ROCKS_LOG_WARN(rep_->ioptions.info_log,
"Error when seeking to properties block from file: %s",
s.ToString().c_str());
} else if (found_properties_block) {
s = meta_iter->status();
TableProperties* table_properties = nullptr;
if (s.ok()) {
s = ReadProperties(
meta_iter->value(), rep_->file.get(), prefetch_buffer, rep_->footer,
rep_->ioptions, &table_properties, true /* verify_checksum */,
nullptr /* ret_block_handle */, nullptr /* ret_block_contents */,
false /* compression_type_missing */, nullptr /* memory_allocator */);
}
if (s.IsCorruption()) {
s = TryReadPropertiesWithGlobalSeqno(prefetch_buffer, meta_iter->value(),
&table_properties);
}
std::unique_ptr<TableProperties> props_guard;
if (table_properties != nullptr) {
props_guard.reset(table_properties);
}
if (!s.ok()) {
ROCKS_LOG_WARN(rep_->ioptions.info_log,
"Encountered error while reading data from properties "
"block %s",
s.ToString().c_str());
} else {
assert(table_properties != nullptr);
rep_->table_properties.reset(props_guard.release());
rep_->blocks_maybe_compressed =
rep_->table_properties->compression_name !=
CompressionTypeToString(kNoCompression);
rep_->blocks_definitely_zstd_compressed =
(rep_->table_properties->compression_name ==
CompressionTypeToString(kZSTD) ||
rep_->table_properties->compression_name ==
CompressionTypeToString(kZSTDNotFinalCompression));
}
} else {
ROCKS_LOG_ERROR(rep_->ioptions.info_log,
"Cannot find Properties block from file.");
}
#ifndef ROCKSDB_LITE
if (rep_->table_properties) {
ParseSliceTransform(rep_->table_properties->prefix_extractor_name,
&(rep_->table_prefix_extractor));
}
#endif // ROCKSDB_LITE
// Read the table properties, if provided.
if (rep_->table_properties) {
rep_->whole_key_filtering &=
IsFeatureSupported(*(rep_->table_properties),
BlockBasedTablePropertyNames::kWholeKeyFiltering,
rep_->ioptions.info_log);
rep_->prefix_filtering &=
IsFeatureSupported(*(rep_->table_properties),
BlockBasedTablePropertyNames::kPrefixFiltering,
rep_->ioptions.info_log);
rep_->index_key_includes_seq =
rep_->table_properties->index_key_is_user_key == 0;
rep_->index_value_is_full =
rep_->table_properties->index_value_is_delta_encoded == 0;
// Update index_type with the true type.
// If table properties don't contain index type, we assume that the table
// is in very old format and has kBinarySearch index type.
auto& props = rep_->table_properties->user_collected_properties;
auto pos = props.find(BlockBasedTablePropertyNames::kIndexType);
if (pos != props.end()) {
rep_->index_type = static_cast<BlockBasedTableOptions::IndexType>(
DecodeFixed32(pos->second.c_str()));
}
rep_->index_has_first_key =
rep_->index_type == BlockBasedTableOptions::kBinarySearchWithFirstKey;
s = GetGlobalSequenceNumber(*(rep_->table_properties), largest_seqno,
&(rep_->global_seqno));
if (!s.ok()) {
ROCKS_LOG_ERROR(rep_->ioptions.info_log, "%s", s.ToString().c_str());
}
}
return s;
}
Status BlockBasedTable::ReadRangeDelBlock(
FilePrefetchBuffer* prefetch_buffer, InternalIterator* meta_iter,
const InternalKeyComparator& internal_comparator,
BlockCacheLookupContext* lookup_context) {
Status s;
bool found_range_del_block;
BlockHandle range_del_handle;
s = SeekToRangeDelBlock(meta_iter, &found_range_del_block, &range_del_handle);
if (!s.ok()) {
ROCKS_LOG_WARN(
rep_->ioptions.info_log,
"Error when seeking to range delete tombstones block from file: %s",
s.ToString().c_str());
} else if (found_range_del_block && !range_del_handle.IsNull()) {
ReadOptions read_options;
std::unique_ptr<InternalIterator> iter(NewDataBlockIterator<DataBlockIter>(
read_options, range_del_handle,
/*input_iter=*/nullptr, BlockType::kRangeDeletion,
/*get_context=*/nullptr, lookup_context, Status(), prefetch_buffer));
assert(iter != nullptr);
s = iter->status();
if (!s.ok()) {
ROCKS_LOG_WARN(
rep_->ioptions.info_log,
"Encountered error while reading data from range del block %s",
s.ToString().c_str());
} else {
rep_->fragmented_range_dels =
std::make_shared<FragmentedRangeTombstoneList>(std::move(iter),
internal_comparator);
}
}
return s;
}
Status BlockBasedTable::ReadCompressionDictBlock(
FilePrefetchBuffer* prefetch_buffer,
std::unique_ptr<const BlockContents>* compression_dict_block) const {
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*/,
BlockType::kCompressionDictionary, 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(
FilePrefetchBuffer* prefetch_buffer, InternalIterator* meta_iter,
BlockBasedTable* new_table, bool prefetch_all,
const BlockBasedTableOptions& table_options, const int level,
BlockCacheLookupContext* lookup_context) {
Status s;
// Find filter handle and filter type
if (rep_->filter_policy) {
for (auto filter_type :
{Rep::FilterType::kFullFilter, Rep::FilterType::kPartitionedFilter,
Rep::FilterType::kBlockFilter}) {
std::string prefix;
switch (filter_type) {
case Rep::FilterType::kFullFilter:
prefix = kFullFilterBlockPrefix;
break;
case Rep::FilterType::kPartitionedFilter:
prefix = kPartitionedFilterBlockPrefix;
break;
case Rep::FilterType::kBlockFilter:
prefix = kFilterBlockPrefix;
break;
default:
assert(0);
}
std::string filter_block_key = prefix;
filter_block_key.append(rep_->filter_policy->Name());
if (FindMetaBlock(meta_iter, filter_block_key, &rep_->filter_handle)
.ok()) {
rep_->filter_type = filter_type;
break;
}
}
}
// Find compression dictionary handle
bool found_compression_dict = false;
s = SeekToCompressionDictBlock(meta_iter, &found_compression_dict,
&rep_->compression_dict_handle);
if (!s.ok()) {
return s;
}
BlockBasedTableOptions::IndexType index_type = rep_->index_type;
const bool use_cache = table_options.cache_index_and_filter_blocks;
// pin both index and filters, down to all partitions
const bool pin_all =
rep_->table_options.pin_l0_filter_and_index_blocks_in_cache && level == 0;
// prefetch the first level of index
const bool prefetch_index =
prefetch_all ||
(table_options.pin_top_level_index_and_filter &&
index_type == BlockBasedTableOptions::kTwoLevelIndexSearch);
// pin the first level of index
const bool pin_index =
pin_all || (table_options.pin_top_level_index_and_filter &&
index_type == BlockBasedTableOptions::kTwoLevelIndexSearch);
std::unique_ptr<IndexReader> index_reader;
s = new_table->CreateIndexReader(prefetch_buffer, meta_iter, use_cache,
prefetch_index, pin_index, lookup_context,
&index_reader);
if (!s.ok()) {
return s;
}
rep_->index_reader = std::move(index_reader);
// The partitions of partitioned index are always stored in cache. They
// are hence follow the configuration for pin and prefetch regardless of
// the value of cache_index_and_filter_blocks
if (prefetch_all) {
rep_->index_reader->CacheDependencies(pin_all);
}
// prefetch the first level of filter
const bool prefetch_filter =
prefetch_all ||
(table_options.pin_top_level_index_and_filter &&
rep_->filter_type == Rep::FilterType::kPartitionedFilter);
// Partition fitlers cannot be enabled without partition indexes
assert(!prefetch_filter || prefetch_index);
// pin the first level of filter
const bool pin_filter =
pin_all || (table_options.pin_top_level_index_and_filter &&
rep_->filter_type == Rep::FilterType::kPartitionedFilter);
if (rep_->filter_policy) {
auto filter = new_table->CreateFilterBlockReader(
prefetch_buffer, use_cache, prefetch_filter, pin_filter,
lookup_context);
if (filter) {
// Refer to the comment above about paritioned indexes always being cached
if (prefetch_all) {
filter->CacheDependencies(pin_all);
}
rep_->filter = std::move(filter);
}
}
// TODO(ajkr): also prefetch compression dictionary block
// TODO(ajkr): also pin compression dictionary block when
// `pin_l0_filter_and_index_blocks_in_cache == true`.
if (!table_options.cache_index_and_filter_blocks) {
std::unique_ptr<const BlockContents> compression_dict_block;
s = ReadCompressionDictBlock(prefetch_buffer, &compression_dict_block);
if (!s.ok()) {
return s;
}
if (!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));
}
}
assert(s.ok());
return s;
}
void BlockBasedTable::SetupForCompaction() {
switch (rep_->ioptions.access_hint_on_compaction_start) {
case Options::NONE:
break;
case Options::NORMAL:
rep_->file->file()->Hint(RandomAccessFile::NORMAL);
break;
case Options::SEQUENTIAL:
rep_->file->file()->Hint(RandomAccessFile::SEQUENTIAL);
break;
case Options::WILLNEED:
rep_->file->file()->Hint(RandomAccessFile::WILLNEED);
break;
default:
assert(false);
}
}
std::shared_ptr<const TableProperties> BlockBasedTable::GetTableProperties()
const {
return rep_->table_properties;
}
size_t BlockBasedTable::ApproximateMemoryUsage() const {
size_t usage = 0;
if (rep_->filter) {
usage += rep_->filter->ApproximateMemoryUsage();
}
if (rep_->index_reader) {
usage += rep_->index_reader->ApproximateMemoryUsage();
}
if (rep_->uncompression_dict) {
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(FilePrefetchBuffer* prefetch_buffer,
std::unique_ptr<Block>* meta_block,
std::unique_ptr<InternalIterator>* iter) {
// TODO(sanjay): Skip this if footer.metaindex_handle() size indicates
// it is an empty block.
std::unique_ptr<Block> meta;
Status s = ReadBlockFromFile(
rep_->file.get(), prefetch_buffer, rep_->footer, ReadOptions(),
rep_->footer.metaindex_handle(), &meta, rep_->ioptions,
true /* decompress */, true /*maybe_compressed*/, BlockType::kMetaIndex,
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options,
kDisableGlobalSequenceNumber, 0 /* read_amp_bytes_per_bit */,
GetMemoryAllocator(rep_->table_options));
if (!s.ok()) {
ROCKS_LOG_ERROR(rep_->ioptions.info_log,
"Encountered error while reading data from properties"
" block %s",
s.ToString().c_str());
return s;
}
*meta_block = std::move(meta);
// meta block uses bytewise comparator.
iter->reset(meta_block->get()->NewDataIterator(BytewiseComparator(),
BytewiseComparator()));
return Status::OK();
}
template <typename TBlocklike>
class BlocklikeTraits;
template <>
class BlocklikeTraits<BlockContents> {
public:
static BlockContents* Create(BlockContents&& contents,
SequenceNumber /* global_seqno */,
size_t /* read_amp_bytes_per_bit */,
Statistics* /* statistics */) {
return new BlockContents(std::move(contents));
}
static uint32_t GetNumRestarts(const BlockContents& /* contents */) {
return 0;
}
};
template <>
class BlocklikeTraits<Block> {
public:
static Block* Create(BlockContents&& contents, SequenceNumber global_seqno,
size_t read_amp_bytes_per_bit, Statistics* statistics) {
return new Block(std::move(contents), global_seqno, read_amp_bytes_per_bit,
statistics);
}
static uint32_t GetNumRestarts(const Block& block) {
return block.NumRestarts();
}
};
template <typename TBlocklike>
Status BlockBasedTable::GetDataBlockFromCache(
const Slice& block_cache_key, const Slice& compressed_block_cache_key,
Cache* block_cache, Cache* block_cache_compressed,
const ReadOptions& read_options, CachableEntry<TBlocklike>* block,
const UncompressionDict& uncompression_dict, BlockType block_type,
GetContext* get_context) const {
const size_t read_amp_bytes_per_bit =
block_type == BlockType::kData
? rep_->table_options.read_amp_bytes_per_bit
: 0;
assert(block);
assert(block->IsEmpty());
Status s;
BlockContents* compressed_block = nullptr;
Cache::Handle* block_cache_compressed_handle = nullptr;
// Lookup uncompressed cache first
if (block_cache != nullptr) {
auto cache_handle = GetEntryFromCache(block_cache, block_cache_key,
block_type, get_context);
if (cache_handle != nullptr) {
block->SetCachedValue(
reinterpret_cast<TBlocklike*>(block_cache->Value(cache_handle)),
block_cache, cache_handle);
return s;
}
}
// If not found, search from the compressed block cache.
assert(block->IsEmpty());
if (block_cache_compressed == nullptr) {
return s;
}
assert(!compressed_block_cache_key.empty());
block_cache_compressed_handle =
block_cache_compressed->Lookup(compressed_block_cache_key);
Statistics* statistics = rep_->ioptions.statistics;
// if we found in the compressed cache, then uncompress and insert into
// uncompressed cache
if (block_cache_compressed_handle == nullptr) {
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_MISS);
return s;
}
// found compressed block
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_HIT);
compressed_block = reinterpret_cast<BlockContents*>(
block_cache_compressed->Value(block_cache_compressed_handle));
CompressionType compression_type = compressed_block->get_compression_type();
assert(compression_type != kNoCompression);
// Retrieve the uncompressed contents into a new buffer
BlockContents contents;
UncompressionContext context(compression_type);
UncompressionInfo info(context, uncompression_dict, compression_type);
s = UncompressBlockContents(
info, compressed_block->data.data(), compressed_block->data.size(),
&contents, rep_->table_options.format_version, rep_->ioptions,
GetMemoryAllocator(rep_->table_options));
// Insert uncompressed block into block cache
if (s.ok()) {
std::unique_ptr<TBlocklike> block_holder(
BlocklikeTraits<TBlocklike>::Create(
std::move(contents), rep_->get_global_seqno(block_type),
read_amp_bytes_per_bit, statistics)); // uncompressed block
if (block_cache != nullptr && block_holder->own_bytes() &&
read_options.fill_cache) {
size_t charge = block_holder->ApproximateMemoryUsage();
Cache::Handle* cache_handle = nullptr;
s = block_cache->Insert(block_cache_key, block_holder.get(), charge,
&DeleteCachedEntry<TBlocklike>, &cache_handle);
#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);
UpdateCacheInsertionMetrics(block_type, get_context, charge);
} else {
RecordTick(statistics, BLOCK_CACHE_ADD_FAILURES);
}
} else {
block->SetOwnedValue(block_holder.release());
}
}
// Release hold on compressed cache entry
block_cache_compressed->Release(block_cache_compressed_handle);
return s;
}
template <typename TBlocklike>
Status BlockBasedTable::PutDataBlockToCache(
const Slice& block_cache_key, const Slice& compressed_block_cache_key,
Cache* block_cache, Cache* block_cache_compressed,
CachableEntry<TBlocklike>* cached_block, BlockContents* raw_block_contents,
CompressionType raw_block_comp_type,
const UncompressionDict& uncompression_dict, SequenceNumber seq_no,
MemoryAllocator* memory_allocator, BlockType block_type,
GetContext* get_context) const {
const ImmutableCFOptions& ioptions = rep_->ioptions;
const uint32_t format_version = rep_->table_options.format_version;
const size_t read_amp_bytes_per_bit =
block_type == BlockType::kData
? rep_->table_options.read_amp_bytes_per_bit
: 0;
const Cache::Priority priority =
rep_->table_options.cache_index_and_filter_blocks_with_high_priority &&
(block_type == BlockType::kFilter ||
block_type == BlockType::kCompressionDictionary ||
block_type == BlockType::kIndex)
? Cache::Priority::HIGH
: Cache::Priority::LOW;
assert(cached_block);
assert(cached_block->IsEmpty());
Status s;
Statistics* statistics = ioptions.statistics;
std::unique_ptr<TBlocklike> block_holder;
if (raw_block_comp_type != kNoCompression) {
// Retrieve the uncompressed contents into a new buffer
BlockContents uncompressed_block_contents;
UncompressionContext context(raw_block_comp_type);
UncompressionInfo info(context, uncompression_dict, raw_block_comp_type);
s = UncompressBlockContents(info, raw_block_contents->data.data(),
raw_block_contents->data.size(),
&uncompressed_block_contents, format_version,
ioptions, memory_allocator);
if (!s.ok()) {
return s;
}
block_holder.reset(BlocklikeTraits<TBlocklike>::Create(
std::move(uncompressed_block_contents), seq_no, read_amp_bytes_per_bit,
statistics));
} else {
block_holder.reset(BlocklikeTraits<TBlocklike>::Create(
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<TBlocklike>, &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);
UpdateCacheInsertionMetrics(block_type, get_context, charge);
} else {
RecordTick(statistics, BLOCK_CACHE_ADD_FAILURES);
}
} else {
cached_block->SetOwnedValue(block_holder.release());
}
return s;
}
std::unique_ptr<FilterBlockReader> BlockBasedTable::CreateFilterBlockReader(
FilePrefetchBuffer* prefetch_buffer, bool use_cache, bool prefetch,
bool pin, BlockCacheLookupContext* lookup_context) {
auto& rep = rep_;
auto filter_type = rep->filter_type;
if (filter_type == Rep::FilterType::kNoFilter) {
return std::unique_ptr<FilterBlockReader>();
}
assert(rep->filter_policy);
switch (filter_type) {
case Rep::FilterType::kPartitionedFilter:
return PartitionedFilterBlockReader::Create(
this, prefetch_buffer, use_cache, prefetch, pin, lookup_context);
case Rep::FilterType::kBlockFilter:
return BlockBasedFilterBlockReader::Create(
this, prefetch_buffer, use_cache, prefetch, pin, lookup_context);
case Rep::FilterType::kFullFilter:
return FullFilterBlockReader::Create(this, prefetch_buffer, use_cache,
prefetch, pin, lookup_context);
default:
// filter_type is either kNoFilter (exited the function at the first if),
// or it must be covered in this switch block
assert(false);
return std::unique_ptr<FilterBlockReader>();
}
}
CachableEntry<UncompressionDict> BlockBasedTable::GetUncompressionDict(
FilePrefetchBuffer* prefetch_buffer, bool no_io, GetContext* get_context,
BlockCacheLookupContext* lookup_context) const {
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,
BlockType::kCompressionDictionary, get_context);
UncompressionDict* dict = nullptr;
bool is_cache_hit = false;
size_t usage = 0;
if (cache_handle != nullptr) {
dict = reinterpret_cast<UncompressionDict*>(
rep_->table_options.block_cache->Value(cache_handle));
is_cache_hit = true;
usage = dict->ApproximateMemoryUsage();
} else if (no_io) {
// Do not invoke any io.
} else {
std::unique_ptr<const BlockContents> compression_dict_block;
Status s =
ReadCompressionDictBlock(prefetch_buffer, &compression_dict_block);
if (s.ok()) {
assert(compression_dict_block != nullptr);
// TODO(ajkr): find a way to avoid the `compression_dict_block` data copy
std::unique_ptr<UncompressionDict> uncompression_dict(
new UncompressionDict(compression_dict_block->data.ToString(),
rep_->blocks_definitely_zstd_compressed,
rep_->ioptions.statistics));
usage = uncompression_dict->ApproximateMemoryUsage();
s = rep_->table_options.block_cache->Insert(
cache_key, uncompression_dict.get(), usage,
&DeleteCachedUncompressionDictEntry, &cache_handle,
rep_->table_options.cache_index_and_filter_blocks_with_high_priority
? Cache::Priority::HIGH
: Cache::Priority::LOW);
if (s.ok()) {
UpdateCacheInsertionMetrics(BlockType::kCompressionDictionary,
get_context, usage);
dict = uncompression_dict.release();
} else {
RecordTick(rep_->ioptions.statistics, BLOCK_CACHE_ADD_FAILURES);
assert(dict == nullptr);
assert(cache_handle == nullptr);
}
}
}
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled() &&
lookup_context) {
// Avoid making copy of block_key and cf_name when constructing the access
// record.
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", TraceType::kBlockTraceUncompressionDictBlock,
/*block_size=*/usage, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_context->caller, is_cache_hit,
/*no_insert=*/no_io, lookup_context->get_id);
block_cache_tracer_->WriteBlockAccess(access_record, cache_key,
rep_->cf_name_for_tracing(),
/*referenced_key=*/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<IndexValue>* BlockBasedTable::NewIndexIterator(
const ReadOptions& read_options, bool disable_prefix_seek,
IndexBlockIter* input_iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) const {
assert(rep_ != nullptr);
assert(rep_->index_reader != nullptr);
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
return rep_->index_reader->NewIterator(read_options, disable_prefix_seek,
input_iter, get_context,
lookup_context);
}
// Convert an index iterator value (i.e., an encoded BlockHandle)
// into an iterator over the contents of the corresponding block.
// If input_iter is null, new a iterator
// If input_iter is not null, update this iter and return it
template <typename TBlockIter>
TBlockIter* BlockBasedTable::NewDataBlockIterator(
const ReadOptions& ro, const BlockHandle& handle, TBlockIter* input_iter,
BlockType block_type, GetContext* get_context,
BlockCacheLookupContext* lookup_context, Status s,
FilePrefetchBuffer* prefetch_buffer, bool for_compaction) const {
PERF_TIMER_GUARD(new_table_block_iter_nanos);
TBlockIter* iter = input_iter != nullptr ? input_iter : new TBlockIter;
if (!s.ok()) {
iter->Invalidate(s);
return iter;
}
const bool no_io = (ro.read_tier == kBlockCacheTier);
auto uncompression_dict_storage =
GetUncompressionDict(prefetch_buffer, no_io, get_context, lookup_context);
const UncompressionDict& uncompression_dict =
uncompression_dict_storage.GetValue() == nullptr
? UncompressionDict::GetEmptyDict()
: *uncompression_dict_storage.GetValue();
CachableEntry<Block> block;
s = RetrieveBlock(prefetch_buffer, ro, handle, uncompression_dict, &block,
block_type, get_context, lookup_context, for_compaction);
if (!s.ok()) {
assert(block.IsEmpty());
iter->Invalidate(s);
return iter;
}
assert(block.GetValue() != nullptr);
// Block contents are pinned and it is still pinned after the iterator
// is destroyed as long as cleanup functions are moved to another object,
// when:
// 1. block cache handle is set to be released in cleanup function, or
// 2. it's pointing to immortal source. If own_bytes is true then we are
// not reading data from the original source, whether immortal or not.
// Otherwise, the block is pinned iff the source is immortal.
const bool block_contents_pinned =
block.IsCached() ||
(!block.GetValue()->own_bytes() && rep_->immortal_table);
iter = InitBlockIterator<TBlockIter>(rep_, block.GetValue(), iter,
block_contents_pinned);
if (!block.IsCached()) {
if (!ro.fill_cache && rep_->cache_key_prefix_size != 0) {
// insert a dummy record to block cache to track the memory usage
Cache* const block_cache = rep_->table_options.block_cache.get();
Cache::Handle* cache_handle = nullptr;
// There are two other types of cache keys: 1) SST cache key added in
// `MaybeReadBlockAndLoadToCache` 2) dummy cache key added in
// `write_buffer_manager`. Use longer prefix (41 bytes) to differentiate
// from SST cache key(31 bytes), and use non-zero prefix to
// differentiate from `write_buffer_manager`
const size_t kExtraCacheKeyPrefix = kMaxVarint64Length * 4 + 1;
char cache_key[kExtraCacheKeyPrefix + kMaxVarint64Length];
// Prefix: use rep_->cache_key_prefix padded by 0s
memset(cache_key, 0, kExtraCacheKeyPrefix + kMaxVarint64Length);
assert(rep_->cache_key_prefix_size != 0);
assert(rep_->cache_key_prefix_size <= kExtraCacheKeyPrefix);
memcpy(cache_key, rep_->cache_key_prefix, rep_->cache_key_prefix_size);
char* end = EncodeVarint64(cache_key + kExtraCacheKeyPrefix,
next_cache_key_id_++);
assert(end - cache_key <=
static_cast<int>(kExtraCacheKeyPrefix + kMaxVarint64Length));
const Slice unique_key(cache_key, static_cast<size_t>(end - cache_key));
s = block_cache->Insert(unique_key, nullptr,
block.GetValue()->ApproximateMemoryUsage(),
nullptr, &cache_handle);
if (s.ok()) {
assert(cache_handle != nullptr);
iter->RegisterCleanup(&ForceReleaseCachedEntry, block_cache,
cache_handle);
}
}
} else {
iter->SetCacheHandle(block.GetCacheHandle());
}
block.TransferTo(iter);
return iter;
}
template <>
DataBlockIter* BlockBasedTable::InitBlockIterator<DataBlockIter>(
const Rep* rep, Block* block, DataBlockIter* input_iter,
bool block_contents_pinned) {
return block->NewDataIterator(
&rep->internal_comparator, rep->internal_comparator.user_comparator(),
input_iter, rep->ioptions.statistics, block_contents_pinned);
}
template <>
IndexBlockIter* BlockBasedTable::InitBlockIterator<IndexBlockIter>(
const Rep* rep, Block* block, IndexBlockIter* input_iter,
bool block_contents_pinned) {
return block->NewIndexIterator(
&rep->internal_comparator, rep->internal_comparator.user_comparator(),
input_iter, rep->ioptions.statistics, /* total_order_seek */ true,
rep->index_has_first_key, rep->index_key_includes_seq,
rep->index_value_is_full, block_contents_pinned);
}
// Convert an uncompressed data block (i.e CachableEntry<Block>)
// into an iterator over the contents of the corresponding block.
// If input_iter is null, new a iterator
// If input_iter is not null, update this iter and return it
template <typename TBlockIter>
TBlockIter* BlockBasedTable::NewDataBlockIterator(
const ReadOptions& ro, CachableEntry<Block>& block, TBlockIter* input_iter,
Status s) const {
PERF_TIMER_GUARD(new_table_block_iter_nanos);
TBlockIter* iter = input_iter != nullptr ? input_iter : new TBlockIter;
if (!s.ok()) {
iter->Invalidate(s);
return iter;
}
assert(block.GetValue() != nullptr);
// Block contents are pinned and it is still pinned after the iterator
// is destroyed as long as cleanup functions are moved to another object,
// when:
// 1. block cache handle is set to be released in cleanup function, or
// 2. it's pointing to immortal source. If own_bytes is true then we are
// not reading data from the original source, whether immortal or not.
// Otherwise, the block is pinned iff the source is immortal.
const bool block_contents_pinned =
block.IsCached() ||
(!block.GetValue()->own_bytes() && rep_->immortal_table);
iter = InitBlockIterator<TBlockIter>(rep_, block.GetValue(), iter,
block_contents_pinned);
if (!block.IsCached()) {
if (!ro.fill_cache && rep_->cache_key_prefix_size != 0) {
// insert a dummy record to block cache to track the memory usage
Cache* const block_cache = rep_->table_options.block_cache.get();
Cache::Handle* cache_handle = nullptr;
// There are two other types of cache keys: 1) SST cache key added in
// `MaybeReadBlockAndLoadToCache` 2) dummy cache key added in
// `write_buffer_manager`. Use longer prefix (41 bytes) to differentiate
// from SST cache key(31 bytes), and use non-zero prefix to
// differentiate from `write_buffer_manager`
const size_t kExtraCacheKeyPrefix = kMaxVarint64Length * 4 + 1;
char cache_key[kExtraCacheKeyPrefix + kMaxVarint64Length];
// Prefix: use rep_->cache_key_prefix padded by 0s
memset(cache_key, 0, kExtraCacheKeyPrefix + kMaxVarint64Length);
assert(rep_->cache_key_prefix_size != 0);
assert(rep_->cache_key_prefix_size <= kExtraCacheKeyPrefix);
memcpy(cache_key, rep_->cache_key_prefix, rep_->cache_key_prefix_size);
char* end = EncodeVarint64(cache_key + kExtraCacheKeyPrefix,
next_cache_key_id_++);
assert(end - cache_key <=
static_cast<int>(kExtraCacheKeyPrefix + kMaxVarint64Length));
const Slice unique_key(cache_key, static_cast<size_t>(end - cache_key));
s = block_cache->Insert(unique_key, nullptr,
block.GetValue()->ApproximateMemoryUsage(),
nullptr, &cache_handle);
if (s.ok()) {
assert(cache_handle != nullptr);
iter->RegisterCleanup(&ForceReleaseCachedEntry, block_cache,
cache_handle);
}
}
} else {
iter->SetCacheHandle(block.GetCacheHandle());
}
block.TransferTo(iter);
return iter;
}
// Lookup the cache for the given data block referenced by an index iterator
// value (i.e BlockHandle). If it exists in the cache, initialize block to
// the contents of the data block.
Status BlockBasedTable::GetDataBlockFromCache(
const ReadOptions& ro, const BlockHandle& handle,
const UncompressionDict& uncompression_dict,
CachableEntry<Block>* block, BlockType block_type,
GetContext* get_context) const {
BlockCacheLookupContext lookup_data_block_context(
TableReaderCaller::kUserMultiGet);
Status s = RetrieveBlock(nullptr, ro, handle, uncompression_dict, block,
block_type, get_context, &lookup_data_block_context);
if (s.IsIncomplete()) {
s = Status::OK();
}
return s;
}
// If contents is nullptr, this function looks up the block caches for the
// data block referenced by handle, and read the block from disk if necessary.
// If contents is non-null, it skips the cache lookup and disk read, since
// the caller has already read it. In both cases, if ro.fill_cache is true,
// it inserts the block into the block cache.
template <typename TBlocklike>
Status BlockBasedTable::MaybeReadBlockAndLoadToCache(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<TBlocklike>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
BlockContents* contents) const {
assert(block_entry != nullptr);
const bool no_io = (ro.read_tier == kBlockCacheTier);
Cache* block_cache = rep_->table_options.block_cache.get();
// No point to cache compressed blocks if it never goes away
Cache* block_cache_compressed =
rep_->immortal_table ? nullptr
: rep_->table_options.block_cache_compressed.get();
// First, try to get the block from the cache
//
// If either block cache is enabled, we'll try to read from it.
Status s;
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
char compressed_cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
Slice key /* key to the block cache */;
Slice ckey /* key to the compressed block cache */;
bool is_cache_hit = false;
bool no_insert = true;
if (block_cache != nullptr || block_cache_compressed != nullptr) {
// create key for block cache
if (block_cache != nullptr) {
key = GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
handle, cache_key);
}
if (block_cache_compressed != nullptr) {
ckey = GetCacheKey(rep_->compressed_cache_key_prefix,
rep_->compressed_cache_key_prefix_size, handle,
compressed_cache_key);
}
if (!contents) {
s = GetDataBlockFromCache(key, ckey, block_cache, block_cache_compressed,
ro, block_entry, uncompression_dict, block_type,
get_context);
if (block_entry->GetValue()) {
// TODO(haoyu): Differentiate cache hit on uncompressed block cache and
// compressed block cache.
is_cache_hit = true;
}
}
// Can't find the block from the cache. If I/O is allowed, read from the
// file.
if (block_entry->GetValue() == nullptr && !no_io && ro.fill_cache) {
no_insert = false;
Statistics* statistics = rep_->ioptions.statistics;
const bool maybe_compressed =
block_type != BlockType::kFilter && rep_->blocks_maybe_compressed;
const bool do_uncompress = maybe_compressed && !block_cache_compressed;
CompressionType raw_block_comp_type;
BlockContents raw_block_contents;
if (!contents) {
StopWatch sw(rep_->ioptions.env, statistics, READ_BLOCK_GET_MICROS);
BlockFetcher block_fetcher(
rep_->file.get(), prefetch_buffer, rep_->footer, ro, handle,
&raw_block_contents, rep_->ioptions, do_uncompress,
maybe_compressed, block_type, uncompression_dict,
rep_->persistent_cache_options,
GetMemoryAllocator(rep_->table_options),
GetMemoryAllocatorForCompressedBlock(rep_->table_options));
s = block_fetcher.ReadBlockContents();
raw_block_comp_type = block_fetcher.get_compression_type();
contents = &raw_block_contents;
} else {
raw_block_comp_type = contents->get_compression_type();
}
if (s.ok()) {
SequenceNumber seq_no = rep_->get_global_seqno(block_type);
// If filling cache is allowed and a cache is configured, try to put the
// block to the cache.
s = PutDataBlockToCache(key, ckey, block_cache, block_cache_compressed,
block_entry, contents,
raw_block_comp_type, uncompression_dict, seq_no,
GetMemoryAllocator(rep_->table_options),
block_type, get_context);
}
}
}
// Fill lookup_context.
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled() &&
lookup_context) {
size_t usage = 0;
uint64_t nkeys = 0;
if (block_entry->GetValue()) {
// Approximate the number of keys in the block using restarts.
nkeys =
rep_->table_options.block_restart_interval *
BlocklikeTraits<TBlocklike>::GetNumRestarts(*block_entry->GetValue());
usage = block_entry->GetValue()->ApproximateMemoryUsage();
}
TraceType trace_block_type = TraceType::kTraceMax;
switch (block_type) {
case BlockType::kData:
trace_block_type = TraceType::kBlockTraceDataBlock;
break;
case BlockType::kFilter:
trace_block_type = TraceType::kBlockTraceFilterBlock;
break;
case BlockType::kRangeDeletion:
trace_block_type = TraceType::kBlockTraceRangeDeletionBlock;
break;
case BlockType::kIndex:
trace_block_type = TraceType::kBlockTraceIndexBlock;
break;
default:
// This cannot happen.
assert(false);
break;
}
if (BlockCacheTraceHelper::ShouldTraceReferencedKey(
trace_block_type, lookup_context->caller)) {
// Defer logging the access to Get() and MultiGet() to trace additional
// information, e.g., the referenced key,
// referenced_key_exist_in_block.
// Make a copy of the block key here since it will be logged later.
lookup_context->FillLookupContext(
is_cache_hit, no_insert, trace_block_type,
/*block_size=*/usage, /*block_key=*/key.ToString(), nkeys);
} else {
// Avoid making copy of block_key and cf_name when constructing the access
// record.
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", trace_block_type,
/*block_size=*/usage, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_context->caller, is_cache_hit,
no_insert, lookup_context->get_id);
block_cache_tracer_->WriteBlockAccess(access_record, key,
rep_->cf_name_for_tracing(),
/*referenced_key=*/nullptr);
}
}
assert(s.ok() || block_entry->GetValue() == nullptr);
return s;
}
// This function reads multiple data blocks from disk using Env::MultiRead()
// and optionally inserts them into the block cache. It uses the scratch
// buffer provided by the caller, which is contiguous. If scratch is a nullptr
// it allocates a separate buffer for each block. Typically, if the blocks
// need to be uncompressed and there is no compressed block cache, callers
// can allocate a temporary scratch buffer in order to minimize memory
// allocations.
// If options.fill_cache is true, it inserts the blocks into cache. If its
// false and scratch is non-null and the blocks are uncompressed, it copies
// the buffers to heap. In any case, the CachableEntry<Block> returned will
// own the data bytes.
// batch - A MultiGetRange with only those keys with unique data blocks not
// found in cache
// handles - A vector of block handles. Some of them me be NULL handles
// scratch - An optional contiguous buffer to read compressed blocks into
void BlockBasedTable::MaybeLoadBlocksToCache(
const ReadOptions& options,
const MultiGetRange* batch,
const autovector<BlockHandle, MultiGetContext::MAX_BATCH_SIZE>* handles,
autovector<Status, MultiGetContext::MAX_BATCH_SIZE>* statuses,
autovector<
CachableEntry<Block>, MultiGetContext::MAX_BATCH_SIZE>* results,
char* scratch,
const UncompressionDict& uncompression_dict) const {
RandomAccessFileReader* file = rep_->file.get();
const Footer& footer = rep_->footer;
const ImmutableCFOptions& ioptions = rep_->ioptions;
SequenceNumber global_seqno = rep_->get_global_seqno(BlockType::kData);
size_t read_amp_bytes_per_bit = rep_->table_options.read_amp_bytes_per_bit;
MemoryAllocator* memory_allocator = GetMemoryAllocator(rep_->table_options);
if (file->use_direct_io() || ioptions.allow_mmap_reads) {
size_t idx_in_batch = 0;
for (auto mget_iter = batch->begin(); mget_iter != batch->end();
++mget_iter, ++idx_in_batch) {
BlockCacheLookupContext lookup_data_block_context(
TableReaderCaller::kUserMultiGet);
const BlockHandle& handle = (*handles)[idx_in_batch];
if (handle.IsNull()) {
continue;
}
(*statuses)[idx_in_batch] = RetrieveBlock(nullptr, options, handle,
uncompression_dict, &(*results)[idx_in_batch], BlockType::kData,
mget_iter->get_context, &lookup_data_block_context);
}
return;
}
autovector<ReadRequest, MultiGetContext::MAX_BATCH_SIZE> read_reqs;
size_t buf_offset = 0;
size_t idx_in_batch = 0;
for (auto mget_iter = batch->begin(); mget_iter != batch->end();
++mget_iter, ++idx_in_batch) {
const BlockHandle& handle = (*handles)[idx_in_batch];
if (handle.IsNull()) {
continue;
}
ReadRequest req;
req.len = handle.size() + kBlockTrailerSize;
if (scratch == nullptr) {
req.scratch = new char[req.len];
} else {
req.scratch = scratch + buf_offset;
buf_offset += req.len;
}
req.offset = handle.offset();
req.status = Status::OK();
read_reqs.emplace_back(req);
}
file->MultiRead(&read_reqs[0], read_reqs.size());
size_t read_req_idx = 0;
idx_in_batch = 0;
for (auto mget_iter = batch->begin(); mget_iter != batch->end();
++mget_iter, ++idx_in_batch) {
const BlockHandle& handle = (*handles)[idx_in_batch];
if (handle.IsNull()) {
continue;
}
ReadRequest& req = read_reqs[read_req_idx++];
Status s = req.status;
if (s.ok()) {
if (req.result.size() != handle.size() + kBlockTrailerSize) {
s = Status::Corruption("truncated block read from " +
rep_->file->file_name() + " offset " +
ToString(handle.offset()) + ", expected " +
ToString(handle.size() + kBlockTrailerSize) +
" bytes, got " + ToString(req.result.size()));
}
}
BlockContents raw_block_contents;
if (s.ok()) {
if (scratch == nullptr) {
// We allocated a buffer for this block. Give ownership of it to
// BlockContents so it can free the memory
assert(req.result.data() == req.scratch);
std::unique_ptr<char[]> raw_block(req.scratch);
raw_block_contents = BlockContents(std::move(raw_block),
handle.size());
} else {
// We used the scratch buffer, so no need to free anything
raw_block_contents = BlockContents(Slice(req.scratch,
handle.size()));
}
#ifndef NDEBUG
raw_block_contents.is_raw_block = true;
#endif
if (options.verify_checksums) {
PERF_TIMER_GUARD(block_checksum_time);
const char* data = req.result.data();
uint32_t expected = DecodeFixed32(data + handle.size() + 1);
s = rocksdb::VerifyChecksum(footer.checksum(), req.result.data(),
handle.size() + 1, expected);
}
}
if (s.ok()) {
if (options.fill_cache) {
BlockCacheLookupContext lookup_data_block_context(
TableReaderCaller::kUserMultiGet);
CachableEntry<Block>* block_entry = &(*results)[idx_in_batch];
// MaybeReadBlockAndLoadToCache will insert into the block caches if
// necessary. Since we're passing the raw block contents, it will
// avoid looking up the block cache
s = MaybeReadBlockAndLoadToCache(nullptr, options, handle,
uncompression_dict, block_entry, BlockType::kData,
mget_iter->get_context, &lookup_data_block_context,
&raw_block_contents);
} else {
CompressionType compression_type =
raw_block_contents.get_compression_type();
BlockContents contents;
if (compression_type != kNoCompression) {
UncompressionContext context(compression_type);
UncompressionInfo info(context, uncompression_dict, compression_type);
s = UncompressBlockContents(info, req.result.data(), handle.size(),
&contents, footer.version(), rep_->ioptions,
memory_allocator);
} else {
if (scratch != nullptr) {
// If we used the scratch buffer, then the contents need to be
// copied to heap
Slice raw = Slice(req.result.data(), handle.size());
contents = BlockContents(CopyBufferToHeap(
GetMemoryAllocator(rep_->table_options), raw),
handle.size());
} else {
contents = std::move(raw_block_contents);
}
}
if (s.ok()) {
(*results)[idx_in_batch].SetOwnedValue(new Block(std::move(contents),
global_seqno, read_amp_bytes_per_bit, ioptions.statistics));
}
}
}
(*statuses)[idx_in_batch] = s;
}
}
template <typename TBlocklike>
Status BlockBasedTable::RetrieveBlock(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<TBlocklike>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
bool for_compaction) const {
assert(block_entry);
assert(block_entry->IsEmpty());
Status s;
if (rep_->table_options.cache_index_and_filter_blocks ||
(block_type != BlockType::kFilter &&
block_type != BlockType::kCompressionDictionary &&
block_type != BlockType::kIndex)) {
s = MaybeReadBlockAndLoadToCache(prefetch_buffer, ro, handle,
uncompression_dict, block_entry,
block_type, get_context, lookup_context,
/*contents=*/nullptr);
if (!s.ok()) {
return s;
}
if (block_entry->GetValue() != nullptr) {
assert(s.ok());
return s;
}
}
assert(block_entry->IsEmpty());
const bool no_io = ro.read_tier == kBlockCacheTier;
if (no_io) {
return Status::Incomplete("no blocking io");
}
const bool maybe_compressed =
block_type != BlockType::kFilter && rep_->blocks_maybe_compressed;
const bool do_uncompress = maybe_compressed;
std::unique_ptr<TBlocklike> block;
{
StopWatch sw(rep_->ioptions.env, rep_->ioptions.statistics,
READ_BLOCK_GET_MICROS);
s = ReadBlockFromFile(
rep_->file.get(), prefetch_buffer, rep_->footer, ro, handle, &block,
rep_->ioptions, do_uncompress, maybe_compressed, block_type,
uncompression_dict, rep_->persistent_cache_options,
rep_->get_global_seqno(block_type),
block_type == BlockType::kData
? rep_->table_options.read_amp_bytes_per_bit
: 0,
GetMemoryAllocator(rep_->table_options), for_compaction);
}
if (!s.ok()) {
return s;
}
block_entry->SetOwnedValue(block.release());
assert(s.ok());
return s;
}
// Explicitly instantiate templates for both "blocklike" types we use.
// This makes it possible to keep the template definitions in the .cc file.
template Status BlockBasedTable::RetrieveBlock<BlockContents>(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<BlockContents>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
bool for_compaction) const;
template Status BlockBasedTable::RetrieveBlock<Block>(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<Block>* block_entry, BlockType block_type,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
bool for_compaction) const;
BlockBasedTable::PartitionedIndexIteratorState::PartitionedIndexIteratorState(
const BlockBasedTable* table,
std::unordered_map<uint64_t, CachableEntry<Block>>* block_map)
: table_(table), block_map_(block_map) {}
InternalIteratorBase<IndexValue>*
BlockBasedTable::PartitionedIndexIteratorState::NewSecondaryIterator(
const BlockHandle& handle) {
// Return a block iterator on the index partition
auto block = block_map_->find(handle.offset());
// This is a possible scenario since block cache might not have had space
// for the partition
if (block != block_map_->end()) {
const Rep* rep = table_->get_rep();
assert(rep);
Statistics* kNullStats = nullptr;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
return block->second.GetValue()->NewIndexIterator(
&rep->internal_comparator, rep->internal_comparator.user_comparator(),
nullptr, kNullStats, true, rep->index_has_first_key,
rep->index_key_includes_seq, rep->index_value_is_full);
}
// Create an empty iterator
return new IndexBlockIter();
}
// This will be broken if the user specifies an unusual implementation
// of Options.comparator, or if the user specifies an unusual
// definition of prefixes in BlockBasedTableOptions.filter_policy.
// In particular, we require the following three properties:
//
// 1) key.starts_with(prefix(key))
// 2) Compare(prefix(key), key) <= 0.
// 3) If Compare(key1, key2) <= 0, then Compare(prefix(key1), prefix(key2)) <= 0
//
// Otherwise, this method guarantees no I/O will be incurred.
//
// REQUIRES: this method shouldn't be called while the DB lock is held.
bool BlockBasedTable::PrefixMayMatch(
const Slice& internal_key, const ReadOptions& read_options,
const SliceTransform* options_prefix_extractor,
const bool need_upper_bound_check,
BlockCacheLookupContext* lookup_context) const {
if (!rep_->filter_policy) {
return true;
}
const SliceTransform* prefix_extractor;
if (rep_->table_prefix_extractor == nullptr) {
if (need_upper_bound_check) {
return true;
}
prefix_extractor = options_prefix_extractor;
} else {
prefix_extractor = rep_->table_prefix_extractor.get();
}
auto user_key = ExtractUserKey(internal_key);
if (!prefix_extractor->InDomain(user_key)) {
return true;
}
bool may_match = true;
Status s;
// First, try check with full filter
FilterBlockReader* const filter = rep_->filter.get();
bool filter_checked = true;
if (filter != nullptr) {
if (!filter->IsBlockBased()) {
const Slice* const const_ikey_ptr = &internal_key;
may_match = filter->RangeMayExist(
read_options.iterate_upper_bound, user_key, prefix_extractor,
rep_->internal_comparator.user_comparator(), const_ikey_ptr,
&filter_checked, need_upper_bound_check, lookup_context);
} else {
// if prefix_extractor changed for block based filter, skip filter
if (need_upper_bound_check) {
return true;
}
auto prefix = prefix_extractor->Transform(user_key);
InternalKey internal_key_prefix(prefix, kMaxSequenceNumber, kTypeValue);
auto internal_prefix = internal_key_prefix.Encode();
// To prevent any io operation in this method, we set `read_tier` to make
// sure we always read index or filter only when they have already been
// loaded to memory.
ReadOptions no_io_read_options;
no_io_read_options.read_tier = kBlockCacheTier;
// Then, try find it within each block
// we already know prefix_extractor and prefix_extractor_name must match
// because `CheckPrefixMayMatch` first checks `check_filter_ == true`
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter(NewIndexIterator(
no_io_read_options,
/*need_upper_bound_check=*/false, /*input_iter=*/nullptr,
/*get_context=*/nullptr, lookup_context));
iiter->Seek(internal_prefix);
if (!iiter->Valid()) {
// we're past end of file
// if it's incomplete, it means that we avoided I/O
// and we're not really sure that we're past the end
// of the file
may_match = iiter->status().IsIncomplete();
} else if ((rep_->index_key_includes_seq ? ExtractUserKey(iiter->key())
: iiter->key())
.starts_with(ExtractUserKey(internal_prefix))) {
// we need to check for this subtle case because our only
// guarantee is that "the key is a string >= last key in that data
// block" according to the doc/table_format.txt spec.
//
// Suppose iiter->key() starts with the desired prefix; it is not
// necessarily the case that the corresponding data block will
// contain the prefix, since iiter->key() need not be in the
// block. However, the next data block may contain the prefix, so
// we return true to play it safe.
may_match = true;
} else if (filter->IsBlockBased()) {
// iiter->key() does NOT start with the desired prefix. Because
// Seek() finds the first key that is >= the seek target, this
// means that iiter->key() > prefix. Thus, any data blocks coming
// after the data block corresponding to iiter->key() cannot
// possibly contain the key. Thus, the corresponding data block
// is the only on could potentially contain the prefix.
BlockHandle handle = iiter->value().handle;
may_match = filter->PrefixMayMatch(
prefix, prefix_extractor, handle.offset(), /*no_io=*/false,
/*const_key_ptr=*/nullptr, /*get_context=*/nullptr, lookup_context);
}
}
}
if (filter_checked) {
Statistics* statistics = rep_->ioptions.statistics;
RecordTick(statistics, BLOOM_FILTER_PREFIX_CHECKED);
if (!may_match) {
RecordTick(statistics, BLOOM_FILTER_PREFIX_USEFUL);
}
}
return may_match;
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::Seek(const Slice& target) {
SeekImpl(&target);
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekToFirst() {
SeekImpl(nullptr);
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekImpl(
const Slice* target) {
is_out_of_bound_ = false;
is_at_first_key_from_index_ = false;
if (target && !CheckPrefixMayMatch(*target)) {
ResetDataIter();
return;
}
bool need_seek_index = true;
if (block_iter_points_to_real_block_ && block_iter_.Valid()) {
// Reseek.
prev_block_offset_ = index_iter_->value().handle.offset();
if (target) {
// We can avoid an index seek if:
// 1. The new seek key is larger than the current key
// 2. The new seek key is within the upper bound of the block
// Since we don't necessarily know the internal key for either
// the current key or the upper bound, we check user keys and
// exclude the equality case. Considering internal keys can
// improve for the boundary cases, but it would complicate the
// code.
if (user_comparator_.Compare(ExtractUserKey(*target),
block_iter_.user_key()) > 0 &&
user_comparator_.Compare(ExtractUserKey(*target),
index_iter_->user_key()) < 0) {
need_seek_index = false;
}
}
}
if (need_seek_index) {
if (target) {
index_iter_->Seek(*target);
} else {
index_iter_->SeekToFirst();
}
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
}
IndexValue v = index_iter_->value();
const bool same_block = block_iter_points_to_real_block_ &&
v.handle.offset() == prev_block_offset_;
// TODO(kolmike): Remove the != kBlockCacheTier condition.
if (!v.first_internal_key.empty() && !same_block &&
(!target || icomp_.Compare(*target, v.first_internal_key) <= 0) &&
read_options_.read_tier != kBlockCacheTier) {
// Index contains the first key of the block, and it's >= target.
// We can defer reading the block.
is_at_first_key_from_index_ = true;
ResetDataIter();
} else {
// Need to use the data block.
if (!same_block) {
InitDataBlock();
}
if (target) {
block_iter_.Seek(*target);
} else {
block_iter_.SeekToFirst();
}
FindKeyForward();
}
CheckDataBlockWithinUpperBound();
CheckOutOfBound();
if (target) {
assert(!Valid() || ((block_type_ == BlockType::kIndex &&
!table_->get_rep()->index_key_includes_seq)
? (user_comparator_.Compare(ExtractUserKey(*target),
key()) <= 0)
: (icomp_.Compare(*target, key()) <= 0)));
}
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekForPrev(
const Slice& target) {
is_out_of_bound_ = false;
is_at_first_key_from_index_ = false;
if (!CheckPrefixMayMatch(target)) {
ResetDataIter();
return;
}
SavePrevIndexValue();
// Call Seek() rather than SeekForPrev() in the index block, because the
// target data block will likely to contain the position for `target`, the
// same as Seek(), rather than than before.
// For example, if we have three data blocks, each containing two keys:
// [2, 4] [6, 8] [10, 12]
// (the keys in the index block would be [4, 8, 12])
// and the user calls SeekForPrev(7), we need to go to the second block,
// just like if they call Seek(7).
// The only case where the block is difference is when they seek to a position
// in the boundary. For example, if they SeekForPrev(5), we should go to the
// first block, rather than the second. However, we don't have the information
// to distinguish the two unless we read the second block. In this case, we'll
// end up with reading two blocks.
index_iter_->Seek(target);
if (!index_iter_->Valid()) {
if (!index_iter_->status().ok()) {
ResetDataIter();
return;
}
index_iter_->SeekToLast();
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
}
InitDataBlock();
block_iter_.SeekForPrev(target);
FindKeyBackward();
CheckDataBlockWithinUpperBound();
assert(!block_iter_.Valid() ||
icomp_.Compare(target, block_iter_.key()) >= 0);
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::SeekToLast() {
is_out_of_bound_ = false;
is_at_first_key_from_index_ = false;
SavePrevIndexValue();
index_iter_->SeekToLast();
if (!index_iter_->Valid()) {
ResetDataIter();
return;
}
InitDataBlock();
block_iter_.SeekToLast();
FindKeyBackward();
CheckDataBlockWithinUpperBound();
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::Next() {
if (is_at_first_key_from_index_ && !MaterializeCurrentBlock()) {
return;
}
assert(block_iter_points_to_real_block_);
block_iter_.Next();
FindKeyForward();
CheckOutOfBound();
}
template <class TBlockIter, typename TValue>
bool BlockBasedTableIterator<TBlockIter, TValue>::NextAndGetResult(
IterateResult* result) {
Next();
bool is_valid = Valid();
if (is_valid) {
result->key = key();
result->may_be_out_of_upper_bound = MayBeOutOfUpperBound();
}
return is_valid;
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::Prev() {
if (is_at_first_key_from_index_) {
is_at_first_key_from_index_ = false;
index_iter_->Prev();
if (!index_iter_->Valid()) {
return;
}
InitDataBlock();
block_iter_.SeekToLast();
} else {
assert(block_iter_points_to_real_block_);
block_iter_.Prev();
}
FindKeyBackward();
}
// 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().handle;
if (!block_iter_points_to_real_block_ ||
data_block_handle.offset() != prev_block_offset_ ||
// if previous attempt of reading the block missed cache, try again
block_iter_.status().IsIncomplete()) {
if (block_iter_points_to_real_block_) {
ResetDataIter();
}
auto* rep = table_->get_rep();
// Prefetch additional data for range scans (iterators). Enabled only for
// user reads.
// Implicit auto readahead:
// Enabled after 2 sequential IOs when ReadOptions.readahead_size == 0.
// Explicit user requested readahead:
// Enabled from the very first IO when ReadOptions.readahead_size is set.
if (lookup_context_.caller != TableReaderCaller::kCompaction) {
if (read_options_.readahead_size == 0) {
// Implicit auto readahead
num_file_reads_++;
if (num_file_reads_ > 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));
}
} else if (!prefetch_buffer_) {
prefetch_buffer_.reset(
new FilePrefetchBuffer(rep->file.get(), compaction_readahead_size_,
compaction_readahead_size_));
}
Status s;
table_->NewDataBlockIterator<TBlockIter>(
read_options_, data_block_handle, &block_iter_, block_type_,
/*get_context=*/nullptr, &lookup_context_, s, prefetch_buffer_.get(),
/*for_compaction=*/lookup_context_.caller ==
TableReaderCaller::kCompaction);
block_iter_points_to_real_block_ = true;
CheckDataBlockWithinUpperBound();
}
}
template <class TBlockIter, typename TValue>
bool BlockBasedTableIterator<TBlockIter, TValue>::MaterializeCurrentBlock() {
assert(is_at_first_key_from_index_);
assert(!block_iter_points_to_real_block_);
assert(index_iter_->Valid());
is_at_first_key_from_index_ = false;
InitDataBlock();
assert(block_iter_points_to_real_block_);
block_iter_.SeekToFirst();
if (!block_iter_.Valid() ||
icomp_.Compare(block_iter_.key(),
index_iter_->value().first_internal_key) != 0) {
// Uh oh.
block_iter_.Invalidate(Status::Corruption(
"first key in index doesn't match first key in block"));
return false;
}
return true;
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::FindKeyForward() {
// This method's code is kept short to make it likely to be inlined.
assert(!is_out_of_bound_);
assert(block_iter_points_to_real_block_);
if (!block_iter_.Valid()) {
// This is the only call site of FindBlockForward(), but it's extracted into
// a separate method to keep FindKeyForward() short and likely to be
// inlined. When transitioning to a different block, we call
// FindBlockForward(), which is much longer and is probably not inlined.
FindBlockForward();
} else {
// This is the fast path that avoids a function call.
}
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::FindBlockForward() {
// TODO the while loop inherits from two-level-iterator. We don't know
// whether a block can be empty so it can be replaced by an "if".
do {
if (!block_iter_.status().ok()) {
return;
}
// Whether next data block is out of upper bound, if there is one.
const bool next_block_is_out_of_bound =
read_options_.iterate_upper_bound != nullptr &&
block_iter_points_to_real_block_ && !data_block_within_upper_bound_;
assert(!next_block_is_out_of_bound ||
user_comparator_.Compare(*read_options_.iterate_upper_bound,
index_iter_->user_key()) <= 0);
ResetDataIter();
index_iter_->Next();
if (next_block_is_out_of_bound) {
// The next block is out of bound. No need to read it.
TEST_SYNC_POINT_CALLBACK("BlockBasedTableIterator:out_of_bound", nullptr);
// We need to make sure this is not the last data block before setting
// is_out_of_bound_, since the index key for the last data block can be
// larger than smallest key of the next file on the same level.
if (index_iter_->Valid()) {
is_out_of_bound_ = true;
}
return;
}
if (!index_iter_->Valid()) {
return;
}
IndexValue v = index_iter_->value();
// TODO(kolmike): Remove the != kBlockCacheTier condition.
if (!v.first_internal_key.empty() &&
read_options_.read_tier != kBlockCacheTier) {
// Index contains the first key of the block. Defer reading the block.
is_at_first_key_from_index_ = true;
return;
}
InitDataBlock();
block_iter_.SeekToFirst();
} while (!block_iter_.Valid());
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::FindKeyBackward() {
while (!block_iter_.Valid()) {
if (!block_iter_.status().ok()) {
return;
}
ResetDataIter();
index_iter_->Prev();
if (index_iter_->Valid()) {
InitDataBlock();
block_iter_.SeekToLast();
} else {
return;
}
}
// We could have check lower bound here too, but we opt not to do it for
// code simplicity.
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::CheckOutOfBound() {
if (read_options_.iterate_upper_bound != nullptr && Valid()) {
is_out_of_bound_ = user_comparator_.Compare(
*read_options_.iterate_upper_bound, user_key()) <= 0;
}
}
template <class TBlockIter, typename TValue>
void BlockBasedTableIterator<TBlockIter, TValue>::CheckDataBlockWithinUpperBound() {
if (read_options_.iterate_upper_bound != nullptr &&
block_iter_points_to_real_block_) {
data_block_within_upper_bound_ =
(user_comparator_.Compare(*read_options_.iterate_upper_bound,
index_iter_->user_key()) > 0);
}
}
InternalIterator* BlockBasedTable::NewIterator(
const ReadOptions& read_options, const SliceTransform* prefix_extractor,
Arena* arena, bool skip_filters, TableReaderCaller caller, size_t compaction_readahead_size) {
BlockCacheLookupContext lookup_context{caller};
bool need_upper_bound_check =
PrefixExtractorChanged(rep_->table_properties.get(), prefix_extractor);
if (arena == nullptr) {
return new BlockBasedTableIterator<DataBlockIter>(
this, read_options, rep_->internal_comparator,
NewIndexIterator(
read_options,
need_upper_bound_check &&
rep_->index_type == BlockBasedTableOptions::kHashSearch,
/*input_iter=*/nullptr, /*get_context=*/nullptr, &lookup_context),
!skip_filters && !read_options.total_order_seek &&
prefix_extractor != nullptr,
need_upper_bound_check, prefix_extractor, BlockType::kData, caller,
compaction_readahead_size);
} else {
auto* mem =
arena->AllocateAligned(sizeof(BlockBasedTableIterator<DataBlockIter>));
return new (mem) BlockBasedTableIterator<DataBlockIter>(
this, read_options, rep_->internal_comparator,
NewIndexIterator(read_options, need_upper_bound_check,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
&lookup_context),
!skip_filters && !read_options.total_order_seek &&
prefix_extractor != nullptr,
need_upper_bound_check, prefix_extractor, BlockType::kData, caller,
compaction_readahead_size);
}
}
FragmentedRangeTombstoneIterator* BlockBasedTable::NewRangeTombstoneIterator(
const ReadOptions& read_options) {
if (rep_->fragmented_range_dels == nullptr) {
return nullptr;
}
SequenceNumber snapshot = kMaxSequenceNumber;
if (read_options.snapshot != nullptr) {
snapshot = read_options.snapshot->GetSequenceNumber();
}
return new FragmentedRangeTombstoneIterator(
rep_->fragmented_range_dels, rep_->internal_comparator, snapshot);
}
bool BlockBasedTable::FullFilterKeyMayMatch(
const ReadOptions& read_options, FilterBlockReader* filter,
const Slice& internal_key, const bool no_io,
const SliceTransform* prefix_extractor, GetContext* get_context,
BlockCacheLookupContext* lookup_context) const {
if (filter == nullptr || filter->IsBlockBased()) {
return true;
}
Slice user_key = ExtractUserKey(internal_key);
const Slice* const const_ikey_ptr = &internal_key;
bool may_match = true;
if (rep_->whole_key_filtering) {
size_t ts_sz =
rep_->internal_comparator.user_comparator()->timestamp_size();
Slice user_key_without_ts = StripTimestampFromUserKey(user_key, ts_sz);
may_match =
filter->KeyMayMatch(user_key_without_ts, prefix_extractor, kNotValid,
no_io, const_ikey_ptr, get_context, lookup_context);
} else if (!read_options.total_order_seek && prefix_extractor &&
rep_->table_properties->prefix_extractor_name.compare(
prefix_extractor->Name()) == 0 &&
prefix_extractor->InDomain(user_key) &&
!filter->PrefixMayMatch(prefix_extractor->Transform(user_key),
prefix_extractor, kNotValid, no_io,
const_ikey_ptr, get_context,
lookup_context)) {
may_match = false;
}
if (may_match) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_FULL_POSITIVE);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_positive, 1, rep_->level);
}
return may_match;
}
void BlockBasedTable::FullFilterKeysMayMatch(
const ReadOptions& read_options, FilterBlockReader* filter,
MultiGetRange* range, const bool no_io,
const SliceTransform* prefix_extractor,
BlockCacheLookupContext* lookup_context) const {
if (filter == nullptr || filter->IsBlockBased()) {
return;
}
if (rep_->whole_key_filtering) {
filter->KeysMayMatch(range, prefix_extractor, kNotValid, no_io,
lookup_context);
} else if (!read_options.total_order_seek && prefix_extractor &&
rep_->table_properties->prefix_extractor_name.compare(
prefix_extractor->Name()) == 0) {
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,
lookup_context);
}
}
Status BlockBasedTable::Get(const ReadOptions& read_options, const Slice& key,
GetContext* get_context,
const SliceTransform* prefix_extractor,
bool skip_filters) {
assert(key.size() >= 8); // key must be internal key
assert(get_context != nullptr);
Status s;
const bool no_io = read_options.read_tier == kBlockCacheTier;
FilterBlockReader* const filter =
!skip_filters ? rep_->filter.get() : nullptr;
// First check the full filter
// If full filter not useful, Then go into each block
uint64_t tracing_get_id = get_context->get_tracing_get_id();
BlockCacheLookupContext lookup_context{TableReaderCaller::kUserGet,
tracing_get_id};
const bool may_match =
FullFilterKeyMayMatch(read_options, filter, key, no_io, prefix_extractor,
get_context, &lookup_context);
if (!may_match) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, 1, rep_->level);
} else {
IndexBlockIter iiter_on_stack;
// if prefix_extractor found in block differs from options, disable
// BlockPrefixIndex. Only do this check when index_type is kHashSearch.
bool need_upper_bound_check = false;
if (rep_->index_type == BlockBasedTableOptions::kHashSearch) {
need_upper_bound_check = PrefixExtractorChanged(
rep_->table_properties.get(), prefix_extractor);
}
auto iiter =
NewIndexIterator(read_options, need_upper_bound_check, &iiter_on_stack,
get_context, &lookup_context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr.reset(iiter);
}
size_t ts_sz =
rep_->internal_comparator.user_comparator()->timestamp_size();
bool matched = false; // if such user key mathced a key in SST
bool done = false;
for (iiter->Seek(key); iiter->Valid() && !done; iiter->Next()) {
IndexValue v = iiter->value();
bool not_exist_in_filter =
filter != nullptr && filter->IsBlockBased() == true &&
!filter->KeyMayMatch(ExtractUserKeyAndStripTimestamp(key, ts_sz),
prefix_extractor, v.handle.offset(), no_io,
/*const_ikey_ptr=*/nullptr, get_context,
&lookup_context);
if (not_exist_in_filter) {
// Not found
// TODO: think about interaction with Merge. If a user key cannot
// cross one data block, we should be fine.
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, 1, rep_->level);
break;
}
if (!v.first_internal_key.empty() && !skip_filters &&
UserComparatorWrapper(rep_->internal_comparator.user_comparator())
.Compare(ExtractUserKey(key),
ExtractUserKey(v.first_internal_key)) < 0) {
// The requested key falls between highest key in previous block and
// lowest key in current block.
break;
}
BlockCacheLookupContext lookup_data_block_context{
TableReaderCaller::kUserGet, tracing_get_id};
bool does_referenced_key_exist = false;
DataBlockIter biter;
uint64_t referenced_data_size = 0;
NewDataBlockIterator<DataBlockIter>(
read_options, v.handle, &biter, BlockType::kData, get_context,
&lookup_data_block_context,
/*s=*/Status(), /*prefetch_buffer*/ nullptr);
if (no_io && biter.status().IsIncomplete()) {
// couldn't get block from block_cache
// Update Saver.state to Found because we are only looking for
// whether we can guarantee the key is not there when "no_io" is set
get_context->MarkKeyMayExist();
break;
}
if (!biter.status().ok()) {
s = biter.status();
break;
}
bool may_exist = biter.SeekForGet(key);
// If user-specified timestamp is supported, we cannot end the search
// just because hash index lookup indicates the key+ts does not exist.
if (!may_exist && ts_sz == 0) {
// HashSeek cannot find the key this block and the the iter is not
// the end of the block, i.e. cannot be in the following blocks
// either. In this case, the seek_key cannot be found, so we break
// from the top level for-loop.
done = true;
} else {
// Call the *saver function on each entry/block until it returns false
for (; biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (!get_context->SaveValue(
parsed_key, biter.value(), &matched,
biter.IsValuePinned() ? &biter : nullptr)) {
if (get_context->State() == GetContext::GetState::kFound) {
does_referenced_key_exist = true;
referenced_data_size = biter.key().size() + biter.value().size();
}
done = true;
break;
}
}
s = biter.status();
}
// Write the block cache access record.
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled()) {
// Avoid making copy of block_key, cf_name, and referenced_key when
// constructing the access record.
Slice referenced_key;
if (does_referenced_key_exist) {
referenced_key = biter.key();
} else {
referenced_key = ExtractUserKey(key);
}
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", lookup_data_block_context.block_type,
lookup_data_block_context.block_size, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_data_block_context.caller,
lookup_data_block_context.is_cache_hit,
lookup_data_block_context.no_insert,
lookup_data_block_context.get_id,
/*referenced_key=*/"", referenced_data_size,
lookup_data_block_context.num_keys_in_block,
does_referenced_key_exist);
block_cache_tracer_->WriteBlockAccess(
access_record, lookup_data_block_context.block_key,
rep_->cf_name_for_tracing(), referenced_key);
}
if (done) {
// Avoid the extra Next which is expensive in two-level indexes
break;
}
}
if (matched && filter != nullptr && !filter->IsBlockBased()) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_FULL_TRUE_POSITIVE);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_true_positive, 1,
rep_->level);
}
if (s.ok()) {
s = iiter->status();
}
}
return s;
}
using MultiGetRange = MultiGetContext::Range;
void BlockBasedTable::MultiGet(const ReadOptions& read_options,
const MultiGetRange* mget_range,
const SliceTransform* prefix_extractor,
bool skip_filters) {
FilterBlockReader* const filter =
!skip_filters ? rep_->filter.get() : nullptr;
MultiGetRange sst_file_range(*mget_range, mget_range->begin(),
mget_range->end());
// First check the full filter
// If full filter not useful, Then go into each block
const bool no_io = read_options.read_tier == kBlockCacheTier;
uint64_t tracing_mget_id = BlockCacheTraceHelper::kReservedGetId;
if (!sst_file_range.empty() && sst_file_range.begin()->get_context) {
tracing_mget_id = sst_file_range.begin()->get_context->get_tracing_get_id();
}
BlockCacheLookupContext lookup_context{TableReaderCaller::kUserMultiGet,
tracing_mget_id};
FullFilterKeysMayMatch(read_options, filter, &sst_file_range, no_io,
prefix_extractor, &lookup_context);
if (skip_filters || !sst_file_range.empty()) {
IndexBlockIter iiter_on_stack;
// if prefix_extractor found in block differs from options, disable
// BlockPrefixIndex. Only do this check when index_type is kHashSearch.
bool need_upper_bound_check = false;
if (rep_->index_type == BlockBasedTableOptions::kHashSearch) {
need_upper_bound_check = PrefixExtractorChanged(
rep_->table_properties.get(), prefix_extractor);
}
auto iiter =
NewIndexIterator(read_options, need_upper_bound_check, &iiter_on_stack,
sst_file_range.begin()->get_context, &lookup_context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr.reset(iiter);
}
uint64_t offset = std::numeric_limits<uint64_t>::max();
autovector<BlockHandle, MultiGetContext::MAX_BATCH_SIZE> block_handles;
autovector<CachableEntry<Block>, MultiGetContext::MAX_BATCH_SIZE> results;
autovector<Status, MultiGetContext::MAX_BATCH_SIZE> statuses;
static const size_t kMultiGetReadStackBufSize = 8192;
char stack_buf[kMultiGetReadStackBufSize];
std::unique_ptr<char[]> block_buf;
{
MultiGetRange data_block_range(sst_file_range, sst_file_range.begin(),
sst_file_range.end());
BlockCacheLookupContext lookup_compression_dict_context(
TableReaderCaller::kUserMultiGet);
auto uncompression_dict_storage = GetUncompressionDict(nullptr, no_io,
sst_file_range.begin()->get_context,
&lookup_compression_dict_context);
const UncompressionDict& uncompression_dict =
uncompression_dict_storage.GetValue() == nullptr
? UncompressionDict::GetEmptyDict()
: *uncompression_dict_storage.GetValue();
size_t total_len = 0;
ReadOptions ro = read_options;
ro.read_tier = kBlockCacheTier;
for (auto miter = data_block_range.begin();
miter != data_block_range.end(); ++miter) {
const Slice& key = miter->ikey;
iiter->Seek(miter->ikey);
IndexValue v;
if (iiter->Valid()) {
v = iiter->value();
}
if (!iiter->Valid() ||
(!v.first_internal_key.empty() && !skip_filters &&
UserComparatorWrapper(rep_->internal_comparator.user_comparator())
.Compare(ExtractUserKey(key),
ExtractUserKey(v.first_internal_key)) < 0)) {
// The requested key falls between highest key in previous block and
// lowest key in current block.
*(miter->s) = iiter->status();
data_block_range.SkipKey(miter);
sst_file_range.SkipKey(miter);
continue;
}
statuses.emplace_back();
results.emplace_back();
if (v.handle.offset() == offset) {
// We're going to reuse the block for this key later on. No need to
// look it up now. Place a null handle
block_handles.emplace_back(BlockHandle::NullBlockHandle());
continue;
}
offset = v.handle.offset();
BlockHandle handle = v.handle;
Status s = GetDataBlockFromCache(ro, handle, uncompression_dict,
&(results.back()), BlockType::kData, miter->get_context);
if (s.ok() && !results.back().IsEmpty()) {
// Found it in the cache. Add NULL handle to indicate there is
// nothing to read from disk
block_handles.emplace_back(BlockHandle::NullBlockHandle());
} else {
block_handles.emplace_back(handle);
total_len += handle.size();
}
}
if (total_len) {
char* scratch = nullptr;
// If the blocks need to be uncompressed and we don't need the
// compressed blocks, then we can use a contiguous block of
// memory to read in all the blocks as it will be temporary
// storage
// 1. If blocks are compressed and compressed block cache is there,
// alloc heap bufs
// 2. If blocks are uncompressed, alloc heap bufs
// 3. If blocks are compressed and no compressed block cache, use
// stack buf
if (rep_->table_options.block_cache_compressed == nullptr &&
rep_->blocks_maybe_compressed) {
if (total_len <= kMultiGetReadStackBufSize) {
scratch = stack_buf;
} else {
scratch = new char[total_len];
block_buf.reset(scratch);
}
}
MaybeLoadBlocksToCache(read_options,
&data_block_range, &block_handles, &statuses, &results,
scratch, uncompression_dict);
}
}
DataBlockIter first_biter;
DataBlockIter next_biter;
size_t idx_in_batch = 0;
for (auto miter = sst_file_range.begin(); miter != sst_file_range.end();
++miter) {
Status s;
GetContext* get_context = miter->get_context;
const Slice& key = miter->ikey;
bool matched = false; // if such user key matched a key in SST
bool done = false;
bool first_block = true;
do {
DataBlockIter* biter = nullptr;
bool reusing_block = true;
uint64_t referenced_data_size = 0;
bool does_referenced_key_exist = false;
BlockCacheLookupContext lookup_data_block_context(
TableReaderCaller::kUserMultiGet, tracing_mget_id);
if (first_block) {
if (!block_handles[idx_in_batch].IsNull() ||
!results[idx_in_batch].IsEmpty()) {
first_biter.Invalidate(Status::OK());
NewDataBlockIterator<DataBlockIter>(
read_options, results[idx_in_batch], &first_biter,
statuses[idx_in_batch]);
reusing_block = false;
}
biter = &first_biter;
idx_in_batch++;
} else {
IndexValue v = iiter->value();
if (!v.first_internal_key.empty() && !skip_filters &&
UserComparatorWrapper(rep_->internal_comparator.user_comparator())
.Compare(ExtractUserKey(key),
ExtractUserKey(v.first_internal_key)) < 0) {
// The requested key falls between highest key in previous block and
// lowest key in current block.
break;
}
next_biter.Invalidate(Status::OK());
NewDataBlockIterator<DataBlockIter>(
read_options, iiter->value().handle, &next_biter,
BlockType::kData, get_context, &lookup_data_block_context,
Status(), nullptr);
biter = &next_biter;
reusing_block = false;
}
if (read_options.read_tier == kBlockCacheTier &&
biter->status().IsIncomplete()) {
// couldn't get block from block_cache
// Update Saver.state to Found because we are only looking for
// whether we can guarantee the key is not there when "no_io" is set
get_context->MarkKeyMayExist();
break;
}
if (!biter->status().ok()) {
s = biter->status();
break;
}
bool may_exist = biter->SeekForGet(key);
if (!may_exist) {
// HashSeek cannot find the key this block and the the iter is not
// the end of the block, i.e. cannot be in the following blocks
// either. In this case, the seek_key cannot be found, so we break
// from the top level for-loop.
break;
}
// Call the *saver function on each entry/block until it returns false
for (; biter->Valid(); biter->Next()) {
ParsedInternalKey parsed_key;
Cleanable dummy;
Cleanable* value_pinner = nullptr;
if (!ParseInternalKey(biter->key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (biter->IsValuePinned()) {
if (reusing_block) {
Cache* block_cache = rep_->table_options.block_cache.get();
assert(biter->cache_handle() != nullptr);
block_cache->Ref(biter->cache_handle());
dummy.RegisterCleanup(&ReleaseCachedEntry, block_cache,
biter->cache_handle());
value_pinner = &dummy;
} else {
value_pinner = biter;
}
}
if (!get_context->SaveValue(parsed_key, biter->value(), &matched,
value_pinner)) {
if (get_context->State() == GetContext::GetState::kFound) {
does_referenced_key_exist = true;
referenced_data_size =
biter->key().size() + biter->value().size();
}
done = true;
break;
}
s = biter->status();
}
// Write the block cache access.
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled()) {
// Avoid making copy of block_key, cf_name, and referenced_key when
// constructing the access record.
Slice referenced_key;
if (does_referenced_key_exist) {
referenced_key = biter->key();
} else {
referenced_key = ExtractUserKey(key);
}
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", lookup_data_block_context.block_type,
lookup_data_block_context.block_size, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_data_block_context.caller,
lookup_data_block_context.is_cache_hit,
lookup_data_block_context.no_insert,
lookup_data_block_context.get_id,
/*referenced_key=*/"", referenced_data_size,
lookup_data_block_context.num_keys_in_block,
does_referenced_key_exist);
block_cache_tracer_->WriteBlockAccess(
access_record, lookup_data_block_context.block_key,
rep_->cf_name_for_tracing(), referenced_key);
}
s = biter->status();
if (done) {
// Avoid the extra Next which is expensive in two-level indexes
break;
}
if (first_block) {
iiter->Seek(key);
}
first_block = false;
iiter->Next();
} while (iiter->Valid());
if (matched && filter != nullptr && !filter->IsBlockBased()) {
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_FULL_TRUE_POSITIVE);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_true_positive, 1,
rep_->level);
}
if (s.ok()) {
s = iiter->status();
}
*(miter->s) = s;
}
}
}
Status BlockBasedTable::Prefetch(const Slice* const begin,
const Slice* const end) {
auto& comparator = rep_->internal_comparator;
UserComparatorWrapper user_comparator(comparator.user_comparator());
// pre-condition
if (begin && end && comparator.Compare(*begin, *end) > 0) {
return Status::InvalidArgument(*begin, *end);
}
BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
IndexBlockIter iiter_on_stack;
auto iiter = NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
&iiter_on_stack, /*get_context=*/nullptr,
&lookup_context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr = std::unique_ptr<InternalIteratorBase<IndexValue>>(iiter);
}
if (!iiter->status().ok()) {
// error opening index iterator
return iiter->status();
}
// indicates if we are on the last page that need to be pre-fetched
bool prefetching_boundary_page = false;
for (begin ? iiter->Seek(*begin) : iiter->SeekToFirst(); iiter->Valid();
iiter->Next()) {
BlockHandle block_handle = iiter->value().handle;
const bool is_user_key = !rep_->index_key_includes_seq;
if (end &&
((!is_user_key && comparator.Compare(iiter->key(), *end) >= 0) ||
(is_user_key &&
user_comparator.Compare(iiter->key(), ExtractUserKey(*end)) >= 0))) {
if (prefetching_boundary_page) {
break;
}
// The index entry represents the last key in the data block.
// We should load this page into memory as well, but no more
prefetching_boundary_page = true;
}
// Load the block specified by the block_handle into the block cache
DataBlockIter biter;
NewDataBlockIterator<DataBlockIter>(
ReadOptions(), block_handle, &biter, /*type=*/BlockType::kData,
/*get_context=*/nullptr, &lookup_context, Status(),
/*prefetch_buffer=*/nullptr);
if (!biter.status().ok()) {
// there was an unexpected error while pre-fetching
return biter.status();
}
}
return Status::OK();
}
Status BlockBasedTable::VerifyChecksum(TableReaderCaller caller) {
Status s;
// Check Meta blocks
std::unique_ptr<Block> meta;
std::unique_ptr<InternalIterator> meta_iter;
s = ReadMetaBlock(nullptr /* prefetch buffer */, &meta, &meta_iter);
if (s.ok()) {
s = VerifyChecksumInMetaBlocks(meta_iter.get());
if (!s.ok()) {
return s;
}
} else {
return s;
}
// Check Data blocks
IndexBlockIter iiter_on_stack;
BlockCacheLookupContext context{caller};
InternalIteratorBase<IndexValue>* iiter = NewIndexIterator(
ReadOptions(), /*need_upper_bound_check=*/false, &iiter_on_stack,
/*get_context=*/nullptr, &context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr = std::unique_ptr<InternalIteratorBase<IndexValue>>(iiter);
}
if (!iiter->status().ok()) {
// error opening index iterator
return iiter->status();
}
s = VerifyChecksumInBlocks(iiter);
return s;
}
Status BlockBasedTable::VerifyChecksumInBlocks(
InternalIteratorBase<IndexValue>* 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().handle;
BlockContents contents;
BlockFetcher block_fetcher(
rep_->file.get(), nullptr /* prefetch buffer */, rep_->footer,
ReadOptions(), handle, &contents, rep_->ioptions,
false /* decompress */, false /*maybe_compressed*/, BlockType::kData,
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options);
s = block_fetcher.ReadBlockContents();
if (!s.ok()) {
break;
}
}
return s;
}
BlockType BlockBasedTable::GetBlockTypeForMetaBlockByName(
const Slice& meta_block_name) {
if (meta_block_name.starts_with(kFilterBlockPrefix) ||
meta_block_name.starts_with(kFullFilterBlockPrefix) ||
meta_block_name.starts_with(kPartitionedFilterBlockPrefix)) {
return BlockType::kFilter;
}
if (meta_block_name == kPropertiesBlock) {
return BlockType::kProperties;
}
if (meta_block_name == kCompressionDictBlock) {
return BlockType::kCompressionDictionary;
}
if (meta_block_name == kRangeDelBlock) {
return BlockType::kRangeDeletion;
}
if (meta_block_name == kHashIndexPrefixesBlock) {
return BlockType::kHashIndexPrefixes;
}
if (meta_block_name == kHashIndexPrefixesMetadataBlock) {
return BlockType::kHashIndexMetadata;
}
assert(false);
return BlockType::kInvalid;
}
Status BlockBasedTable::VerifyChecksumInMetaBlocks(
InternalIteratorBase<Slice>* index_iter) {
Status s;
for (index_iter->SeekToFirst(); index_iter->Valid(); index_iter->Next()) {
s = index_iter->status();
if (!s.ok()) {
break;
}
BlockHandle handle;
Slice input = index_iter->value();
s = handle.DecodeFrom(&input);
BlockContents contents;
const Slice meta_block_name = index_iter->key();
BlockFetcher block_fetcher(
rep_->file.get(), nullptr /* prefetch buffer */, rep_->footer,
ReadOptions(), handle, &contents, rep_->ioptions,
false /* decompress */, false /*maybe_compressed*/,
GetBlockTypeForMetaBlockByName(meta_block_name),
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options);
s = block_fetcher.ReadBlockContents();
if (s.IsCorruption() && meta_block_name == kPropertiesBlock) {
TableProperties* table_properties;
s = TryReadPropertiesWithGlobalSeqno(nullptr /* prefetch_buffer */,
index_iter->value(),
&table_properties);
delete table_properties;
}
if (!s.ok()) {
break;
}
}
return s;
}
bool BlockBasedTable::TEST_BlockInCache(const BlockHandle& handle) const {
assert(rep_ != nullptr);
Cache* const cache = rep_->table_options.block_cache.get();
if (cache == nullptr) {
return false;
}
char cache_key_storage[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
Slice cache_key =
GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size, handle,
cache_key_storage);
Cache::Handle* const cache_handle = cache->Lookup(cache_key);
if (cache_handle == nullptr) {
return false;
}
cache->Release(cache_handle);
return true;
}
bool BlockBasedTable::TEST_KeyInCache(const ReadOptions& options,
const Slice& key) {
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter(NewIndexIterator(
options, /*need_upper_bound_check=*/false, /*input_iter=*/nullptr,
/*get_context=*/nullptr, /*lookup_context=*/nullptr));
iiter->Seek(key);
assert(iiter->Valid());
return TEST_BlockInCache(iiter->value().handle);
}
// REQUIRES: The following fields of rep_ should have already been populated:
// 1. file
// 2. index_handle,
// 3. options
// 4. internal_comparator
// 5. index_type
Status BlockBasedTable::CreateIndexReader(
FilePrefetchBuffer* prefetch_buffer,
InternalIterator* preloaded_meta_index_iter, bool use_cache, bool prefetch,
bool pin, BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
// kHashSearch requires non-empty prefix_extractor but bypass checking
// prefix_extractor here since we have no access to MutableCFOptions.
// Add need_upper_bound_check flag in BlockBasedTable::NewIndexIterator.
// If prefix_extractor does not match prefix_extractor_name from table
// properties, turn off Hash Index by setting total_order_seek to true
switch (rep_->index_type) {
case BlockBasedTableOptions::kTwoLevelIndexSearch: {
return PartitionIndexReader::Create(this, prefetch_buffer, use_cache,
prefetch, pin, lookup_context,
index_reader);
}
case BlockBasedTableOptions::kBinarySearch:
case BlockBasedTableOptions::kBinarySearchWithFirstKey: {
return BinarySearchIndexReader::Create(this, prefetch_buffer, use_cache,
prefetch, pin, lookup_context,
index_reader);
}
case BlockBasedTableOptions::kHashSearch: {
std::unique_ptr<Block> meta_guard;
std::unique_ptr<InternalIterator> meta_iter_guard;
auto meta_index_iter = preloaded_meta_index_iter;
if (meta_index_iter == nullptr) {
auto s = ReadMetaBlock(prefetch_buffer, &meta_guard, &meta_iter_guard);
if (!s.ok()) {
// we simply fall back to binary search in case there is any
// problem with prefix hash index loading.
ROCKS_LOG_WARN(rep_->ioptions.info_log,
"Unable to read the metaindex block."
" Fall back to binary search index.");
return BinarySearchIndexReader::Create(this, prefetch_buffer,
use_cache, prefetch, pin,
lookup_context, index_reader);
}
meta_index_iter = meta_iter_guard.get();
}
return HashIndexReader::Create(this, prefetch_buffer, meta_index_iter,
use_cache, prefetch, pin, lookup_context,
index_reader);
}
default: {
std::string error_message =
"Unrecognized index type: " + ToString(rep_->index_type);
return Status::InvalidArgument(error_message.c_str());
}
}
}
uint64_t BlockBasedTable::ApproximateOffsetOf(const Slice& key,
TableReaderCaller caller) {
BlockCacheLookupContext context(caller);
std::unique_ptr<InternalIteratorBase<IndexValue>> index_iter(
NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_context=*/&context));
index_iter->Seek(key);
uint64_t result;
if (index_iter->Valid()) {
BlockHandle handle = index_iter->value().handle;
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_FilterBlockInCache() const {
assert(rep_ != nullptr);
return TEST_BlockInCache(rep_->filter_handle);
}
bool BlockBasedTable::TEST_IndexBlockInCache() const {
assert(rep_ != nullptr);
return TEST_BlockInCache(rep_->footer.index_handle());
}
Status BlockBasedTable::GetKVPairsFromDataBlocks(
std::vector<KVPairBlock>* kv_pair_blocks) {
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_contex=*/nullptr));
Status s = blockhandles_iter->status();
if (!s.ok()) {
// Cannot read Index Block
return s;
}
for (blockhandles_iter->SeekToFirst(); blockhandles_iter->Valid();
blockhandles_iter->Next()) {
s = blockhandles_iter->status();
if (!s.ok()) {
break;
}
std::unique_ptr<InternalIterator> datablock_iter;
datablock_iter.reset(NewDataBlockIterator<DataBlockIter>(
ReadOptions(), blockhandles_iter->value().handle,
/*input_iter=*/nullptr, /*type=*/BlockType::kData,
/*get_context=*/nullptr, /*lookup_context=*/nullptr, Status(),
/*prefetch_buffer=*/nullptr));
s = datablock_iter->status();
if (!s.ok()) {
// Error reading the block - Skipped
continue;
}
KVPairBlock kv_pair_block;
for (datablock_iter->SeekToFirst(); datablock_iter->Valid();
datablock_iter->Next()) {
s = datablock_iter->status();
if (!s.ok()) {
// Error reading the block - Skipped
break;
}
const Slice& key = datablock_iter->key();
const Slice& value = datablock_iter->value();
std::string key_copy = std::string(key.data(), key.size());
std::string value_copy = std::string(value.data(), value.size());
kv_pair_block.push_back(
std::make_pair(std::move(key_copy), std::move(value_copy)));
}
kv_pair_blocks->push_back(std::move(kv_pair_block));
}
return Status::OK();
}
Status BlockBasedTable::DumpTable(WritableFile* out_file) {
// Output Footer
out_file->Append(
"Footer Details:\n"
"--------------------------------------\n"
" ");
out_file->Append(rep_->footer.ToString().c_str());
out_file->Append("\n");
// Output MetaIndex
out_file->Append(
"Metaindex Details:\n"
"--------------------------------------\n");
std::unique_ptr<Block> meta;
std::unique_ptr<InternalIterator> meta_iter;
Status s = ReadMetaBlock(nullptr /* prefetch_buffer */, &meta, &meta_iter);
if (s.ok()) {
for (meta_iter->SeekToFirst(); meta_iter->Valid(); meta_iter->Next()) {
s = meta_iter->status();
if (!s.ok()) {
return s;
}
if (meta_iter->key() == rocksdb::kPropertiesBlock) {
out_file->Append(" Properties block handle: ");
out_file->Append(meta_iter->value().ToString(true).c_str());
out_file->Append("\n");
} else if (meta_iter->key() == rocksdb::kCompressionDictBlock) {
out_file->Append(" Compression dictionary block handle: ");
out_file->Append(meta_iter->value().ToString(true).c_str());
out_file->Append("\n");
} else if (strstr(meta_iter->key().ToString().c_str(),
"filter.rocksdb.") != nullptr) {
out_file->Append(" Filter block handle: ");
out_file->Append(meta_iter->value().ToString(true).c_str());
out_file->Append("\n");
} else if (meta_iter->key() == rocksdb::kRangeDelBlock) {
out_file->Append(" Range deletion block handle: ");
out_file->Append(meta_iter->value().ToString(true).c_str());
out_file->Append("\n");
}
}
out_file->Append("\n");
} else {
return s;
}
// Output TableProperties
const rocksdb::TableProperties* table_properties;
table_properties = rep_->table_properties.get();
if (table_properties != nullptr) {
out_file->Append(
"Table Properties:\n"
"--------------------------------------\n"
" ");
out_file->Append(table_properties->ToString("\n ", ": ").c_str());
out_file->Append("\n");
}
if (rep_->filter) {
out_file->Append(
"Filter Details:\n"
"--------------------------------------\n"
" ");
out_file->Append(rep_->filter->ToString().c_str());
out_file->Append("\n");
}
// Output Index block
s = DumpIndexBlock(out_file);
if (!s.ok()) {
return s;
}
// Output compression dictionary
if (!rep_->compression_dict_handle.IsNull()) {
std::unique_ptr<const BlockContents> compression_dict_block;
s = ReadCompressionDictBlock(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;
}
// cleanup index, filter, and compression dictionary blocks
// to avoid accessing dangling pointers
if (!rep_->table_options.no_block_cache) {
if (!rep_->compression_dict_handle.IsNull()) {
// Get the compression dictionary block key
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
auto key =
GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
rep_->compression_dict_handle, cache_key);
Cache* const cache = rep_->table_options.block_cache.get();
cache->Erase(key);
}
}
rep_->closed = true;
}
Status BlockBasedTable::DumpIndexBlock(WritableFile* out_file) {
out_file->Append(
"Index Details:\n"
"--------------------------------------\n");
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_contex=*/nullptr));
Status s = blockhandles_iter->status();
if (!s.ok()) {
out_file->Append("Can not read Index Block \n\n");
return s;
}
out_file->Append(" Block key hex dump: Data block handle\n");
out_file->Append(" Block key ascii\n\n");
for (blockhandles_iter->SeekToFirst(); blockhandles_iter->Valid();
blockhandles_iter->Next()) {
s = blockhandles_iter->status();
if (!s.ok()) {
break;
}
Slice key = blockhandles_iter->key();
Slice user_key;
InternalKey ikey;
if (!rep_->index_key_includes_seq) {
user_key = key;
} else {
ikey.DecodeFrom(key);
user_key = ikey.user_key();
}
out_file->Append(" HEX ");
out_file->Append(user_key.ToString(true).c_str());
out_file->Append(": ");
out_file->Append(blockhandles_iter->value()
.ToString(true, rep_->index_has_first_key)
.c_str());
out_file->Append("\n");
std::string str_key = user_key.ToString();
std::string res_key("");
char cspace = ' ';
for (size_t i = 0; i < str_key.size(); i++) {
res_key.append(&str_key[i], 1);
res_key.append(1, cspace);
}
out_file->Append(" ASCII ");
out_file->Append(res_key.c_str());
out_file->Append("\n ------\n");
}
out_file->Append("\n");
return Status::OK();
}
Status BlockBasedTable::DumpDataBlocks(WritableFile* out_file) {
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(ReadOptions(), /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_contex=*/nullptr));
Status s = blockhandles_iter->status();
if (!s.ok()) {
out_file->Append("Can not read Index Block \n\n");
return s;
}
uint64_t datablock_size_min = std::numeric_limits<uint64_t>::max();
uint64_t datablock_size_max = 0;
uint64_t datablock_size_sum = 0;
size_t block_id = 1;
for (blockhandles_iter->SeekToFirst(); blockhandles_iter->Valid();
block_id++, blockhandles_iter->Next()) {
s = blockhandles_iter->status();
if (!s.ok()) {
break;
}
BlockHandle bh = blockhandles_iter->value().handle;
uint64_t datablock_size = bh.size();
datablock_size_min = std::min(datablock_size_min, datablock_size);
datablock_size_max = std::max(datablock_size_max, datablock_size);
datablock_size_sum += datablock_size;
out_file->Append("Data Block # ");
out_file->Append(rocksdb::ToString(block_id));
out_file->Append(" @ ");
out_file->Append(blockhandles_iter->value().handle.ToString(true).c_str());
out_file->Append("\n");
out_file->Append("--------------------------------------\n");
std::unique_ptr<InternalIterator> datablock_iter;
datablock_iter.reset(NewDataBlockIterator<DataBlockIter>(
ReadOptions(), blockhandles_iter->value().handle,
/*input_iter=*/nullptr, /*type=*/BlockType::kData,
/*get_context=*/nullptr, /*lookup_context=*/nullptr, Status(),
/*prefetch_buffer=*/nullptr));
s = datablock_iter->status();
if (!s.ok()) {
out_file->Append("Error reading the block - Skipped \n\n");
continue;
}
for (datablock_iter->SeekToFirst(); datablock_iter->Valid();
datablock_iter->Next()) {
s = datablock_iter->status();
if (!s.ok()) {
out_file->Append("Error reading the block - Skipped \n");
break;
}
DumpKeyValue(datablock_iter->key(), datablock_iter->value(), out_file);
}
out_file->Append("\n");
}
uint64_t num_datablocks = block_id - 1;
if (num_datablocks) {
double datablock_size_avg =
static_cast<double>(datablock_size_sum) / num_datablocks;
out_file->Append("Data Block Summary:\n");
out_file->Append("--------------------------------------");
out_file->Append("\n # data blocks: ");
out_file->Append(rocksdb::ToString(num_datablocks));
out_file->Append("\n min data block size: ");
out_file->Append(rocksdb::ToString(datablock_size_min));
out_file->Append("\n max data block size: ");
out_file->Append(rocksdb::ToString(datablock_size_max));
out_file->Append("\n avg data block size: ");
out_file->Append(rocksdb::ToString(datablock_size_avg));
out_file->Append("\n");
}
return Status::OK();
}
void BlockBasedTable::DumpKeyValue(const Slice& key, const Slice& value,
WritableFile* out_file) {
InternalKey ikey;
ikey.DecodeFrom(key);
out_file->Append(" HEX ");
out_file->Append(ikey.user_key().ToString(true).c_str());
out_file->Append(": ");
out_file->Append(value.ToString(true).c_str());
out_file->Append("\n");
std::string str_key = ikey.user_key().ToString();
std::string str_value = value.ToString();
std::string res_key(""), res_value("");
char cspace = ' ';
for (size_t i = 0; i < str_key.size(); i++) {
if (str_key[i] == '\0') {
res_key.append("\\0", 2);
} else {
res_key.append(&str_key[i], 1);
}
res_key.append(1, cspace);
}
for (size_t i = 0; i < str_value.size(); i++) {
if (str_value[i] == '\0') {
res_value.append("\\0", 2);
} else {
res_value.append(&str_value[i], 1);
}
res_value.append(1, cspace);
}
out_file->Append(" ASCII ");
out_file->Append(res_key.c_str());
out_file->Append(": ");
out_file->Append(res_value.c_str());
out_file->Append("\n ------\n");
}
namespace {
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
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