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rocksdb/table/block_based/block_based_table_reader.cc

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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 <atomic>
#include <cstdint>
#include <limits>
#include <memory>
#include <string>
#include <unordered_set>
#include <utility>
#include <vector>
#include "block_cache.h"
#include "cache/cache_entry_roles.h"
#include "cache/cache_key.h"
#include "db/compaction/compaction_picker.h"
#include "db/dbformat.h"
#include "db/pinned_iterators_manager.h"
#include "file/file_prefetch_buffer.h"
#include "file/file_util.h"
#include "file/random_access_file_reader.h"
#include "logging/logging.h"
#include "monitoring/perf_context_imp.h"
#include "parsed_full_filter_block.h"
#include "port/lang.h"
#include "rocksdb/cache.h"
#include "rocksdb/comparator.h"
#include "rocksdb/convenience.h"
#include "rocksdb/env.h"
#include "rocksdb/file_system.h"
#include "rocksdb/filter_policy.h"
#include "rocksdb/iterator.h"
#include "rocksdb/options.h"
#include "rocksdb/snapshot.h"
#include "rocksdb/statistics.h"
#include "rocksdb/system_clock.h"
#include "rocksdb/table.h"
#include "rocksdb/table_properties.h"
#include "rocksdb/trace_record.h"
#include "table/block_based/binary_search_index_reader.h"
#include "table/block_based/block.h"
#include "table/block_based/block_based_table_factory.h"
#include "table/block_based/block_based_table_iterator.h"
#include "table/block_based/block_prefix_index.h"
#include "table/block_based/block_type.h"
#include "table/block_based/filter_block.h"
#include "table/block_based/filter_policy_internal.h"
#include "table/block_based/full_filter_block.h"
#include "table/block_based/hash_index_reader.h"
#include "table/block_based/partitioned_filter_block.h"
#include "table/block_based/partitioned_index_reader.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/persistent_cache_options.h"
#include "table/sst_file_writer_collectors.h"
#include "table/two_level_iterator.h"
#include "test_util/sync_point.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/stop_watch.h"
#include "util/string_util.h"
namespace ROCKSDB_NAMESPACE {
namespace {
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
// Explicitly instantiate templates for each "blocklike" type we use (and
// before implicit specialization).
// This makes it possible to keep the template definitions in the .cc file.
#define INSTANTIATE_BLOCKLIKE_TEMPLATES(T) \
template Status BlockBasedTable::RetrieveBlock<T>( \
FilePrefetchBuffer * prefetch_buffer, const ReadOptions& ro, \
const BlockHandle& handle, const UncompressionDict& uncompression_dict, \
CachableEntry<T>* out_parsed_block, GetContext* get_context, \
BlockCacheLookupContext* lookup_context, bool for_compaction, \
bool use_cache, bool async_read, bool use_block_cache_for_lookup) const; \
template Status BlockBasedTable::MaybeReadBlockAndLoadToCache<T>( \
FilePrefetchBuffer * prefetch_buffer, const ReadOptions& ro, \
const BlockHandle& handle, const UncompressionDict& uncompression_dict, \
bool for_compaction, CachableEntry<T>* block_entry, \
GetContext* get_context, BlockCacheLookupContext* lookup_context, \
BlockContents* contents, bool async_read, \
bool use_block_cache_for_lookup) const; \
template Status BlockBasedTable::LookupAndPinBlocksInCache<T>( \
const ReadOptions& ro, const BlockHandle& handle, \
CachableEntry<T>* out_parsed_block) const;
INSTANTIATE_BLOCKLIKE_TEMPLATES(ParsedFullFilterBlock);
INSTANTIATE_BLOCKLIKE_TEMPLATES(UncompressionDict);
INSTANTIATE_BLOCKLIKE_TEMPLATES(Block_kData);
INSTANTIATE_BLOCKLIKE_TEMPLATES(Block_kIndex);
INSTANTIATE_BLOCKLIKE_TEMPLATES(Block_kFilterPartitionIndex);
INSTANTIATE_BLOCKLIKE_TEMPLATES(Block_kRangeDeletion);
INSTANTIATE_BLOCKLIKE_TEMPLATES(Block_kMetaIndex);
} // namespace ROCKSDB_NAMESPACE
// Generate the regular and coroutine versions of some methods by
// including block_based_table_reader_sync_and_async.h twice
// Macros in the header will expand differently based on whether
// WITH_COROUTINES or WITHOUT_COROUTINES is defined
// clang-format off
#define WITHOUT_COROUTINES
#include "table/block_based/block_based_table_reader_sync_and_async.h"
#undef WITHOUT_COROUTINES
#define WITH_COROUTINES
#include "table/block_based/block_based_table_reader_sync_and_async.h"
#undef WITH_COROUTINES
// clang-format on
namespace ROCKSDB_NAMESPACE {
extern const uint64_t kBlockBasedTableMagicNumber;
extern const std::string kHashIndexPrefixesBlock;
extern const std::string kHashIndexPrefixesMetadataBlock;
BlockBasedTable::~BlockBasedTable() { delete rep_; }
namespace {
// Read the block identified by "handle" from "file".
// The only relevant option is options.verify_checksums for now.
// On failure return non-OK.
// On success fill *result and return OK - caller owns *result
// @param uncompression_dict Data for presetting the compression library's
// dictionary.
template <typename TBlocklike>
Status ReadAndParseBlockFromFile(
RandomAccessFileReader* file, FilePrefetchBuffer* prefetch_buffer,
const Footer& footer, const ReadOptions& options, const BlockHandle& handle,
std::unique_ptr<TBlocklike>* result, const ImmutableOptions& ioptions,
BlockCreateContext& create_context, bool maybe_compressed,
const UncompressionDict& uncompression_dict,
const PersistentCacheOptions& cache_options,
MemoryAllocator* memory_allocator, bool for_compaction, bool async_read) {
assert(result);
BlockContents contents;
BlockFetcher block_fetcher(
file, prefetch_buffer, footer, options, handle, &contents, ioptions,
/*do_uncompress*/ maybe_compressed, maybe_compressed,
TBlocklike::kBlockType, uncompression_dict, cache_options,
memory_allocator, nullptr, for_compaction);
Status s;
// If prefetch_buffer is not allocated, it will fallback to synchronous
// reading of block contents.
if (async_read && prefetch_buffer != nullptr) {
s = block_fetcher.ReadAsyncBlockContents();
if (!s.ok()) {
return s;
}
} else {
s = block_fetcher.ReadBlockContents();
}
if (s.ok()) {
create_context.Create(result, std::move(contents));
}
return s;
}
// For hash based index, return false if table_properties->prefix_extractor_name
// and prefix_extractor both exist and match, otherwise true.
inline bool PrefixExtractorChangedHelper(
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 != prefix_extractor->AsString()) {
return true;
} else {
return false;
}
}
template <typename TBlocklike>
uint32_t GetBlockNumRestarts(const TBlocklike& block) {
if constexpr (std::is_convertible_v<const TBlocklike&, const Block&>) {
const Block& b = block;
return b.NumRestarts();
} else {
return 0;
}
}
} // namespace
void BlockBasedTable::UpdateCacheHitMetrics(BlockType block_type,
GetContext* get_context,
size_t usage) const {
Statistics* const statistics = rep_->ioptions.stats;
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:
case BlockType::kFilterPartitionIndex:
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.stats;
// 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:
case BlockType::kFilterPartitionIndex:
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, bool redundant,
Statistics* const statistics) {
// TODO: introduce perf counters for block cache insertions
if (get_context) {
++get_context->get_context_stats_.num_cache_add;
if (redundant) {
++get_context->get_context_stats_.num_cache_add_redundant;
}
get_context->get_context_stats_.num_cache_bytes_write += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_ADD);
if (redundant) {
RecordTick(statistics, BLOCK_CACHE_ADD_REDUNDANT);
}
RecordTick(statistics, BLOCK_CACHE_BYTES_WRITE, usage);
}
switch (block_type) {
case BlockType::kFilter:
case BlockType::kFilterPartitionIndex:
if (get_context) {
++get_context->get_context_stats_.num_cache_filter_add;
if (redundant) {
++get_context->get_context_stats_.num_cache_filter_add_redundant;
}
get_context->get_context_stats_.num_cache_filter_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_FILTER_ADD);
if (redundant) {
RecordTick(statistics, BLOCK_CACHE_FILTER_ADD_REDUNDANT);
}
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;
if (redundant) {
++get_context->get_context_stats_
.num_cache_compression_dict_add_redundant;
}
get_context->get_context_stats_
.num_cache_compression_dict_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_ADD);
if (redundant) {
RecordTick(statistics, BLOCK_CACHE_COMPRESSION_DICT_ADD_REDUNDANT);
}
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;
if (redundant) {
++get_context->get_context_stats_.num_cache_index_add_redundant;
}
get_context->get_context_stats_.num_cache_index_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_INDEX_ADD);
if (redundant) {
RecordTick(statistics, BLOCK_CACHE_INDEX_ADD_REDUNDANT);
}
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;
if (redundant) {
++get_context->get_context_stats_.num_cache_data_add_redundant;
}
get_context->get_context_stats_.num_cache_data_bytes_insert += usage;
} else {
RecordTick(statistics, BLOCK_CACHE_DATA_ADD);
if (redundant) {
RecordTick(statistics, BLOCK_CACHE_DATA_ADD_REDUNDANT);
}
RecordTick(statistics, BLOCK_CACHE_DATA_BYTES_INSERT, usage);
}
break;
}
}
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
void BlockBasedTable::SetupBaseCacheKey(const TableProperties* properties,
const std::string& cur_db_session_id,
uint64_t cur_file_number,
OffsetableCacheKey* out_base_cache_key,
bool* out_is_stable) {
// Use a stable cache key if sufficient data is in table properties
std::string db_session_id;
uint64_t file_num;
std::string db_id;
if (properties && !properties->db_session_id.empty() &&
properties->orig_file_number > 0) {
// (Newer SST file case)
// We must have both properties to get a stable unique id because
// CreateColumnFamilyWithImport or IngestExternalFiles can change the
// file numbers on a file.
db_session_id = properties->db_session_id;
file_num = properties->orig_file_number;
// Less critical, populated in earlier release than above
db_id = properties->db_id;
if (out_is_stable) {
*out_is_stable = true;
}
} else {
// (Old SST file case)
// We use (unique) cache keys based on current identifiers. These are at
// least stable across table file close and re-open, but not across
// different DBs nor DB close and re-open.
db_session_id = cur_db_session_id;
file_num = cur_file_number;
// Plumbing through the DB ID to here would be annoying, and of limited
// value because of the case of VersionSet::Recover opening some table
// files and later setting the DB ID. So we just rely on uniqueness
// level provided by session ID.
db_id = "unknown";
if (out_is_stable) {
*out_is_stable = false;
}
}
// Too many tests to update to get these working
// assert(file_num > 0);
// assert(!db_session_id.empty());
// assert(!db_id.empty());
// Minimum block size is 5 bytes; therefore we can trim off two lower bits
// from offsets. See GetCacheKey.
*out_base_cache_key = OffsetableCacheKey(db_id, db_session_id, file_num);
}
CacheKey BlockBasedTable::GetCacheKey(const OffsetableCacheKey& base_cache_key,
const BlockHandle& handle) {
// Minimum block size is 5 bytes; therefore we can trim off two lower bits
// from offet.
return base_cache_key.WithOffset(handle.offset() >> 2);
}
Status BlockBasedTable::Open(
const ReadOptions& read_options, const ImmutableOptions& ioptions,
const EnvOptions& env_options, const BlockBasedTableOptions& table_options,
const InternalKeyComparator& internal_comparator,
std::unique_ptr<RandomAccessFileReader>&& file, uint64_t file_size,
uint8_t block_protection_bytes_per_key,
std::unique_ptr<TableReader>* table_reader, uint64_t tail_size,
std::shared_ptr<CacheReservationManager> table_reader_cache_res_mgr,
const std::shared_ptr<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, const bool force_direct_prefetch,
TailPrefetchStats* tail_prefetch_stats,
BlockCacheTracer* const block_cache_tracer,
size_t max_file_size_for_l0_meta_pin, const std::string& cur_db_session_id,
uint64_t cur_file_num, UniqueId64x2 expected_unique_id,
const bool user_defined_timestamps_persisted) {
table_reader->reset();
Status s;
Footer footer;
std::unique_ptr<FilePrefetchBuffer> prefetch_buffer;
// From read_options, retain deadline, io_timeout, rate_limiter_priority, and
// verify_checksums. In future, we may retain more options.
ReadOptions ro;
ro.deadline = read_options.deadline;
ro.io_timeout = read_options.io_timeout;
ro.rate_limiter_priority = read_options.rate_limiter_priority;
ro.verify_checksums = read_options.verify_checksums;
ro.io_activity = read_options.io_activity;
// 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;
if (!ioptions.allow_mmap_reads) {
s = PrefetchTail(ro, file.get(), file_size, force_direct_prefetch,
tail_prefetch_stats, prefetch_all, preload_all,
&prefetch_buffer, ioptions.stats, tail_size,
ioptions.logger);
// Return error in prefetch path to users.
if (!s.ok()) {
return s;
}
} else {
// Should not prefetch for mmap mode.
prefetch_buffer.reset(new FilePrefetchBuffer(
0 /* readahead_size */, 0 /* max_readahead_size */, false /* enable */,
true /* track_min_offset */));
}
// 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]
IOOptions opts;
s = file->PrepareIOOptions(ro, opts);
if (s.ok()) {
s = ReadFooterFromFile(opts, file.get(), *ioptions.fs,
prefetch_buffer.get(), file_size, &footer,
kBlockBasedTableMagicNumber);
}
if (!s.ok()) {
return s;
}
if (!IsSupportedFormatVersion(footer.format_version())) {
return Status::Corruption(
"Unknown Footer version. Maybe this file was created with newer "
"version of RocksDB?");
}
BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
Rep* rep = new BlockBasedTable::Rep(
ioptions, env_options, table_options, internal_comparator, skip_filters,
file_size, level, immortal_table, user_defined_timestamps_persisted);
rep->file = std::move(file);
rep->footer = footer;
// For fully portable/stable cache keys, we need to read the properties
// block before setting up cache keys. TODO: consider setting up a bootstrap
// cache key for PersistentCache to use for metaindex and properties blocks.
rep->persistent_cache_options = PersistentCacheOptions();
// 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();
rep->create_context.protection_bytes_per_key = block_protection_bytes_per_key;
// Read metaindex
std::unique_ptr<BlockBasedTable> new_table(
new BlockBasedTable(rep, block_cache_tracer));
std::unique_ptr<Block> metaindex;
std::unique_ptr<InternalIterator> metaindex_iter;
s = new_table->ReadMetaIndexBlock(ro, prefetch_buffer.get(), &metaindex,
&metaindex_iter);
if (!s.ok()) {
return s;
}
// Populates table_properties and some fields that depend on it,
// such as index_type.
s = new_table->ReadPropertiesBlock(ro, prefetch_buffer.get(),
metaindex_iter.get(), largest_seqno);
if (!s.ok()) {
return s;
}
// Populate BlockCreateContext
bool blocks_definitely_zstd_compressed =
rep->table_properties &&
(rep->table_properties->compression_name ==
CompressionTypeToString(kZSTD) ||
rep->table_properties->compression_name ==
CompressionTypeToString(kZSTDNotFinalCompression));
rep->create_context = BlockCreateContext(
&rep->table_options, &rep->ioptions, rep->ioptions.stats,
blocks_definitely_zstd_compressed, block_protection_bytes_per_key,
rep->internal_comparator.user_comparator(), rep->index_value_is_full,
rep->index_has_first_key);
// Check expected unique id if provided
if (expected_unique_id != kNullUniqueId64x2) {
auto props = rep->table_properties;
if (!props) {
return Status::Corruption("Missing table properties on file " +
std::to_string(cur_file_num) +
" with known unique ID");
}
UniqueId64x2 actual_unique_id{};
s = GetSstInternalUniqueId(props->db_id, props->db_session_id,
props->orig_file_number, &actual_unique_id,
/*force*/ true);
assert(s.ok()); // because force=true
if (expected_unique_id != actual_unique_id) {
return Status::Corruption(
"Mismatch in unique ID on table file " +
std::to_string(cur_file_num) +
". Expected: " + InternalUniqueIdToHumanString(&expected_unique_id) +
" Actual: " + InternalUniqueIdToHumanString(&actual_unique_id));
}
TEST_SYNC_POINT_CALLBACK("BlockBasedTable::Open::PassedVerifyUniqueId",
&actual_unique_id);
} else {
TEST_SYNC_POINT_CALLBACK("BlockBasedTable::Open::SkippedVerifyUniqueId",
nullptr);
if (ioptions.verify_sst_unique_id_in_manifest && ioptions.logger) {
// A crude but isolated way of reporting unverified files. This should not
// be an ongoing concern so doesn't deserve a place in Statistics IMHO.
static std::atomic<uint64_t> unverified_count{0};
auto prev_count =
unverified_count.fetch_add(1, std::memory_order_relaxed);
if (prev_count == 0) {
ROCKS_LOG_WARN(
ioptions.logger,
"At least one SST file opened without unique ID to verify: %" PRIu64
".sst",
cur_file_num);
} else if (prev_count % 1000 == 0) {
ROCKS_LOG_WARN(
ioptions.logger,
"Another ~1000 SST files opened without unique ID to verify");
}
}
}
// Set up prefix extracto as needed
bool force_null_table_prefix_extractor = false;
TEST_SYNC_POINT_CALLBACK(
"BlockBasedTable::Open::ForceNullTablePrefixExtractor",
&force_null_table_prefix_extractor);
if (force_null_table_prefix_extractor) {
assert(!rep->table_prefix_extractor);
} else if (!PrefixExtractorChangedHelper(rep->table_properties.get(),
prefix_extractor.get())) {
// Establish fast path for unchanged prefix_extractor
rep->table_prefix_extractor = prefix_extractor;
} else {
// Current prefix_extractor doesn't match table
if (rep->table_properties) {
//**TODO: If/When the DBOptions has a registry in it, the ConfigOptions
// will need to use it
ConfigOptions config_options;
Status st = SliceTransform::CreateFromString(
config_options, rep->table_properties->prefix_extractor_name,
&(rep->table_prefix_extractor));
if (!st.ok()) {
//**TODO: Should this be error be returned or swallowed?
ROCKS_LOG_ERROR(rep->ioptions.logger,
"Failed to create prefix extractor[%s]: %s",
rep->table_properties->prefix_extractor_name.c_str(),
st.ToString().c_str());
}
}
}
// With properties loaded, we can set up portable/stable cache keys
SetupBaseCacheKey(rep->table_properties.get(), cur_db_session_id,
cur_file_num, &rep->base_cache_key);
rep->persistent_cache_options =
PersistentCacheOptions(rep->table_options.persistent_cache,
rep->base_cache_key, rep->ioptions.stats);
// TODO(yuzhangyu): handle range deletion entries for UDT in memtable only.
s = new_table->ReadRangeDelBlock(ro, prefetch_buffer.get(),
metaindex_iter.get(), internal_comparator,
&lookup_context);
if (!s.ok()) {
return s;
}
rep->verify_checksum_set_on_open = ro.verify_checksums;
s = new_table->PrefetchIndexAndFilterBlocks(
ro, prefetch_buffer.get(), metaindex_iter.get(), new_table.get(),
prefetch_all, table_options, level, file_size,
max_file_size_for_l0_meta_pin, &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());
}
}
if (s.ok() && table_reader_cache_res_mgr) {
std::size_t mem_usage = new_table->ApproximateMemoryUsage();
s = table_reader_cache_res_mgr->MakeCacheReservation(
mem_usage, &(rep->table_reader_cache_res_handle));
if (s.IsMemoryLimit()) {
s = Status::MemoryLimit(
"Can't allocate " +
kCacheEntryRoleToCamelString[static_cast<std::uint32_t>(
CacheEntryRole::kBlockBasedTableReader)] +
" due to memory limit based on "
"cache capacity for memory allocation");
}
}
if (s.ok()) {
*table_reader = std::move(new_table);
}
return s;
}
Status BlockBasedTable::PrefetchTail(
const ReadOptions& ro, RandomAccessFileReader* file, uint64_t file_size,
bool force_direct_prefetch, TailPrefetchStats* tail_prefetch_stats,
const bool prefetch_all, const bool preload_all,
std::unique_ptr<FilePrefetchBuffer>* prefetch_buffer, Statistics* stats,
uint64_t tail_size, Logger* const logger) {
assert(tail_size <= file_size);
size_t tail_prefetch_size = 0;
if (tail_size != 0) {
tail_prefetch_size = tail_size;
} else {
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;
ROCKS_LOG_WARN(logger,
"Tail prefetch size %zu is calculated based on heuristics",
tail_prefetch_size);
} else {
ROCKS_LOG_WARN(
logger,
"Tail prefetch size %zu is calculated based on TailPrefetchStats",
tail_prefetch_size);
}
}
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;
}
#ifndef NDEBUG
std::pair<size_t*, size_t*> prefetch_off_len_pair = {&prefetch_off,
&prefetch_len};
TEST_SYNC_POINT_CALLBACK("BlockBasedTable::Open::TailPrefetchLen",
&prefetch_off_len_pair);
#endif // NDEBUG
IOOptions opts;
Status s = file->PrepareIOOptions(ro, opts);
// Try file system prefetch
if (s.ok() && !file->use_direct_io() && !force_direct_prefetch) {
if (!file->Prefetch(opts, prefetch_off, prefetch_len).IsNotSupported()) {
prefetch_buffer->reset(new FilePrefetchBuffer(
0 /* readahead_size */, 0 /* max_readahead_size */,
false /* enable */, true /* track_min_offset */));
return Status::OK();
}
}
// Use `FilePrefetchBuffer`
prefetch_buffer->reset(new FilePrefetchBuffer(
0 /* readahead_size */, 0 /* max_readahead_size */, true /* enable */,
true /* track_min_offset */, false /* implicit_auto_readahead */,
0 /* num_file_reads */, 0 /* num_file_reads_for_auto_readahead */,
0 /* upper_bound_offset */, nullptr /* fs */, nullptr /* clock */, stats,
/* readahead_cb */ nullptr,
FilePrefetchBufferUsage::kTableOpenPrefetchTail));
if (s.ok()) {
s = (*prefetch_buffer)->Prefetch(opts, file, prefetch_off, prefetch_len);
}
return s;
}
Status BlockBasedTable::ReadPropertiesBlock(
const ReadOptions& ro, FilePrefetchBuffer* prefetch_buffer,
InternalIterator* meta_iter, const SequenceNumber largest_seqno) {
Status s;
BlockHandle handle;
s = FindOptionalMetaBlock(meta_iter, kPropertiesBlockName, &handle);
if (!s.ok()) {
ROCKS_LOG_WARN(rep_->ioptions.logger,
"Error when seeking to properties block from file: %s",
s.ToString().c_str());
} else if (!handle.IsNull()) {
s = meta_iter->status();
std::unique_ptr<TableProperties> table_properties;
if (s.ok()) {
s = ReadTablePropertiesHelper(
ro, handle, rep_->file.get(), prefetch_buffer, rep_->footer,
rep_->ioptions, &table_properties, nullptr /* memory_allocator */);
}
IGNORE_STATUS_IF_ERROR(s);
if (!s.ok()) {
ROCKS_LOG_WARN(rep_->ioptions.logger,
"Encountered error while reading data from properties "
"block %s",
s.ToString().c_str());
} else {
assert(table_properties != nullptr);
rep_->table_properties = std::move(table_properties);
rep_->blocks_maybe_compressed =
rep_->table_properties->compression_name !=
CompressionTypeToString(kNoCompression);
}
} else {
ROCKS_LOG_ERROR(rep_->ioptions.logger,
"Cannot find Properties block from file.");
}
// Read the table properties, if provided.
if (rep_->table_properties) {
rep_->whole_key_filtering &=
IsFeatureSupported(*(rep_->table_properties),
BlockBasedTablePropertyNames::kWholeKeyFiltering,
rep_->ioptions.logger);
rep_->prefix_filtering &= IsFeatureSupported(
*(rep_->table_properties),
BlockBasedTablePropertyNames::kPrefixFiltering, rep_->ioptions.logger);
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 index_type_pos = props.find(BlockBasedTablePropertyNames::kIndexType);
if (index_type_pos != props.end()) {
rep_->index_type = static_cast<BlockBasedTableOptions::IndexType>(
DecodeFixed32(index_type_pos->second.c_str()));
}
auto min_ts_pos = props.find("rocksdb.timestamp_min");
if (min_ts_pos != props.end()) {
rep_->min_timestamp = Slice(min_ts_pos->second);
}
auto max_ts_pos = props.find("rocksdb.timestamp_max");
if (max_ts_pos != props.end()) {
rep_->max_timestamp = Slice(max_ts_pos->second);
}
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.logger, "%s", s.ToString().c_str());
}
}
return s;
}
Status BlockBasedTable::ReadRangeDelBlock(
const ReadOptions& read_options, FilePrefetchBuffer* prefetch_buffer,
InternalIterator* meta_iter,
const InternalKeyComparator& internal_comparator,
BlockCacheLookupContext* lookup_context) {
Status s;
BlockHandle range_del_handle;
s = FindOptionalMetaBlock(meta_iter, kRangeDelBlockName, &range_del_handle);
if (!s.ok()) {
ROCKS_LOG_WARN(
rep_->ioptions.logger,
"Error when seeking to range delete tombstones block from file: %s",
s.ToString().c_str());
} else if (!range_del_handle.IsNull()) {
Status tmp_status;
std::unique_ptr<InternalIterator> iter(NewDataBlockIterator<DataBlockIter>(
read_options, range_del_handle,
/*input_iter=*/nullptr, BlockType::kRangeDeletion,
/*get_context=*/nullptr, lookup_context, prefetch_buffer,
/*for_compaction= */ false, /*async_read= */ false, tmp_status,
/*use_block_cache_for_lookup=*/true));
assert(iter != nullptr);
s = iter->status();
if (!s.ok()) {
ROCKS_LOG_WARN(
rep_->ioptions.logger,
"Encountered error while reading data from range del block %s",
s.ToString().c_str());
IGNORE_STATUS_IF_ERROR(s);
} else {
rep_->fragmented_range_dels =
std::make_shared<FragmentedRangeTombstoneList>(std::move(iter),
internal_comparator);
}
}
return s;
}
Status BlockBasedTable::PrefetchIndexAndFilterBlocks(
const ReadOptions& ro, FilePrefetchBuffer* prefetch_buffer,
InternalIterator* meta_iter, BlockBasedTable* new_table, bool prefetch_all,
const BlockBasedTableOptions& table_options, const int level,
size_t file_size, size_t max_file_size_for_l0_meta_pin,
BlockCacheLookupContext* lookup_context) {
// Find filter handle and filter type
if (rep_->filter_policy) {
auto name = rep_->filter_policy->CompatibilityName();
bool builtin_compatible =
strcmp(name, BuiltinFilterPolicy::kCompatibilityName()) == 0;
for (const auto& [filter_type, prefix] :
{std::make_pair(Rep::FilterType::kFullFilter, kFullFilterBlockPrefix),
std::make_pair(Rep::FilterType::kPartitionedFilter,
kPartitionedFilterBlockPrefix),
std::make_pair(Rep::FilterType::kNoFilter,
kObsoleteFilterBlockPrefix)}) {
if (builtin_compatible) {
// This code is only here to deal with a hiccup in early 7.0.x where
// there was an unintentional name change in the SST files metadata.
// It should be OK to remove this in the future (late 2022) and just
// have the 'else' code.
// NOTE: the test:: names below are likely not needed but included
// out of caution
static const std::unordered_set<std::string> kBuiltinNameAndAliases = {
BuiltinFilterPolicy::kCompatibilityName(),
test::LegacyBloomFilterPolicy::kClassName(),
test::FastLocalBloomFilterPolicy::kClassName(),
test::Standard128RibbonFilterPolicy::kClassName(),
"rocksdb.internal.DeprecatedBlockBasedBloomFilter",
BloomFilterPolicy::kClassName(),
RibbonFilterPolicy::kClassName(),
};
// For efficiency, do a prefix seek and see if the first match is
// good.
meta_iter->Seek(prefix);
if (meta_iter->status().ok() && meta_iter->Valid()) {
Slice key = meta_iter->key();
if (key.starts_with(prefix)) {
key.remove_prefix(prefix.size());
if (kBuiltinNameAndAliases.find(key.ToString()) !=
kBuiltinNameAndAliases.end()) {
Slice v = meta_iter->value();
Status s = rep_->filter_handle.DecodeFrom(&v);
if (s.ok()) {
rep_->filter_type = filter_type;
if (filter_type == Rep::FilterType::kNoFilter) {
ROCKS_LOG_WARN(rep_->ioptions.logger,
"Detected obsolete filter type in %s. Read "
"performance might suffer until DB is fully "
"re-compacted.",
rep_->file->file_name().c_str());
}
break;
}
}
}
}
} else {
std::string filter_block_key = prefix + name;
if (FindMetaBlock(meta_iter, filter_block_key, &rep_->filter_handle)
.ok()) {
rep_->filter_type = filter_type;
if (filter_type == Rep::FilterType::kNoFilter) {
ROCKS_LOG_WARN(
rep_->ioptions.logger,
"Detected obsolete filter type in %s. Read performance might "
"suffer until DB is fully re-compacted.",
rep_->file->file_name().c_str());
}
break;
}
}
}
}
// Partition filters cannot be enabled without partition indexes
assert(rep_->filter_type != Rep::FilterType::kPartitionedFilter ||
rep_->index_type == BlockBasedTableOptions::kTwoLevelIndexSearch);
// Find compression dictionary handle
Status s = FindOptionalMetaBlock(meta_iter, kCompressionDictBlockName,
&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;
const bool maybe_flushed =
level == 0 && file_size <= max_file_size_for_l0_meta_pin;
std::function<bool(PinningTier, PinningTier)> is_pinned =
[maybe_flushed, &is_pinned](PinningTier pinning_tier,
PinningTier fallback_pinning_tier) {
// Fallback to fallback would lead to infinite recursion. Disallow it.
assert(fallback_pinning_tier != PinningTier::kFallback);
switch (pinning_tier) {
case PinningTier::kFallback:
return is_pinned(fallback_pinning_tier,
PinningTier::kNone /* fallback_pinning_tier */);
case PinningTier::kNone:
return false;
case PinningTier::kFlushedAndSimilar:
return maybe_flushed;
case PinningTier::kAll:
return true;
};
// In GCC, this is needed to suppress `control reaches end of non-void
// function [-Werror=return-type]`.
assert(false);
return false;
};
const bool pin_top_level_index = is_pinned(
table_options.metadata_cache_options.top_level_index_pinning,
table_options.pin_top_level_index_and_filter ? PinningTier::kAll
: PinningTier::kNone);
const bool pin_partition =
is_pinned(table_options.metadata_cache_options.partition_pinning,
table_options.pin_l0_filter_and_index_blocks_in_cache
? PinningTier::kFlushedAndSimilar
: PinningTier::kNone);
const bool pin_unpartitioned =
is_pinned(table_options.metadata_cache_options.unpartitioned_pinning,
table_options.pin_l0_filter_and_index_blocks_in_cache
? PinningTier::kFlushedAndSimilar
: PinningTier::kNone);
// pin the first level of index
const bool pin_index =
index_type == BlockBasedTableOptions::kTwoLevelIndexSearch
? pin_top_level_index
: pin_unpartitioned;
// prefetch the first level of index
// WART: this might be redundant (unnecessary cache hit) if !pin_index,
// depending on prepopulate_block_cache option
const bool prefetch_index = prefetch_all || pin_index;
std::unique_ptr<IndexReader> index_reader;
s = new_table->CreateIndexReader(ro, 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 || pin_partition) {
s = rep_->index_reader->CacheDependencies(ro, pin_partition,
prefetch_buffer);
}
if (!s.ok()) {
return s;
}
// pin the first level of filter
const bool pin_filter =
rep_->filter_type == Rep::FilterType::kPartitionedFilter
? pin_top_level_index
: pin_unpartitioned;
// prefetch the first level of filter
// WART: this might be redundant (unnecessary cache hit) if !pin_filter,
// depending on prepopulate_block_cache option
const bool prefetch_filter = prefetch_all || pin_filter;
if (rep_->filter_policy) {
auto filter = new_table->CreateFilterBlockReader(
ro, 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 || pin_partition) {
s = filter->CacheDependencies(ro, pin_partition, prefetch_buffer);
if (!s.ok()) {
return s;
}
}
rep_->filter = std::move(filter);
}
}
if (!rep_->compression_dict_handle.IsNull()) {
std::unique_ptr<UncompressionDictReader> uncompression_dict_reader;
s = UncompressionDictReader::Create(
this, ro, prefetch_buffer, use_cache, prefetch_all || pin_unpartitioned,
pin_unpartitioned, lookup_context, &uncompression_dict_reader);
if (!s.ok()) {
return s;
}
rep_->uncompression_dict_reader = std::move(uncompression_dict_reader);
}
assert(s.ok());
return s;
}
void BlockBasedTable::SetupForCompaction() {}
std::shared_ptr<const TableProperties> BlockBasedTable::GetTableProperties()
const {
return rep_->table_properties;
}
size_t BlockBasedTable::ApproximateMemoryUsage() const {
size_t usage = 0;
if (rep_) {
usage += rep_->ApproximateMemoryUsage();
} else {
return usage;
}
if (rep_->filter) {
usage += rep_->filter->ApproximateMemoryUsage();
}
if (rep_->index_reader) {
usage += rep_->index_reader->ApproximateMemoryUsage();
}
if (rep_->uncompression_dict_reader) {
usage += rep_->uncompression_dict_reader->ApproximateMemoryUsage();
}
if (rep_->table_properties) {
usage += rep_->table_properties->ApproximateMemoryUsage();
}
return usage;
}
// Load the meta-index-block from the file. On success, return the loaded
// metaindex
// block and its iterator.
Status BlockBasedTable::ReadMetaIndexBlock(
const ReadOptions& ro, FilePrefetchBuffer* prefetch_buffer,
std::unique_ptr<Block>* metaindex_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_kMetaIndex> metaindex;
Status s = ReadAndParseBlockFromFile(
rep_->file.get(), prefetch_buffer, rep_->footer, ro,
rep_->footer.metaindex_handle(), &metaindex, rep_->ioptions,
rep_->create_context, true /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options,
GetMemoryAllocator(rep_->table_options), false /* for_compaction */,
false /* async_read */);
if (!s.ok()) {
ROCKS_LOG_ERROR(rep_->ioptions.logger,
"Encountered error while reading data from properties"
" block %s",
s.ToString().c_str());
return s;
}
*metaindex_block = std::move(metaindex);
// meta block uses bytewise comparator.
iter->reset(metaindex_block->get()->NewMetaIterator());
return Status::OK();
}
template <typename TBlocklike>
Cache::Priority BlockBasedTable::GetCachePriority() const {
// Here we treat the legacy name "...index_and_filter_blocks..." to mean all
// metadata blocks that might go into block cache, EXCEPT only those needed
// for the read path (Get, etc.). TableProperties should not be needed on the
// read path (prefix extractor setting is an O(1) size special case that we
// are working not to require from TableProperties), so it is not given
// high-priority treatment if it should go into BlockCache.
if constexpr (TBlocklike::kBlockType == BlockType::kData ||
TBlocklike::kBlockType == BlockType::kProperties) {
return Cache::Priority::LOW;
} else if (rep_->table_options
.cache_index_and_filter_blocks_with_high_priority) {
return Cache::Priority::HIGH;
} else {
return Cache::Priority::LOW;
}
}
template <typename TBlocklike>
WithBlocklikeCheck<Status, TBlocklike> BlockBasedTable::GetDataBlockFromCache(
const Slice& cache_key, BlockCacheInterface<TBlocklike> block_cache,
CachableEntry<TBlocklike>* out_parsed_block, GetContext* get_context,
const UncompressionDict* dict) const {
assert(out_parsed_block);
assert(out_parsed_block->IsEmpty());
Status s;
Statistics* statistics = rep_->ioptions.statistics.get();
// Lookup uncompressed cache first
if (block_cache) {
BlockCreateContext create_ctx = rep_->create_context;
create_ctx.dict = dict;
assert(!cache_key.empty());
auto cache_handle = block_cache.LookupFull(
cache_key, &create_ctx, GetCachePriority<TBlocklike>(), statistics,
rep_->ioptions.lowest_used_cache_tier);
// Avoid updating metrics here if the handle is not complete yet. This
// happens with MultiGet and secondary cache. So update the metrics only
// if its a miss, or a hit and value is ready
if (!cache_handle) {
UpdateCacheMissMetrics(TBlocklike::kBlockType, get_context);
} else {
TBlocklike* value = block_cache.Value(cache_handle);
if (value) {
UpdateCacheHitMetrics(TBlocklike::kBlockType, get_context,
block_cache.get()->GetUsage(cache_handle));
}
out_parsed_block->SetCachedValue(value, block_cache.get(), cache_handle);
return s;
}
}
// If not found, search from the compressed block cache.
assert(out_parsed_block->IsEmpty());
return s;
}
template <typename TBlocklike>
WithBlocklikeCheck<Status, TBlocklike> BlockBasedTable::PutDataBlockToCache(
const Slice& cache_key, BlockCacheInterface<TBlocklike> block_cache,
CachableEntry<TBlocklike>* out_parsed_block,
BlockContents&& uncompressed_block_contents,
BlockContents&& compressed_block_contents, CompressionType block_comp_type,
const UncompressionDict& uncompression_dict,
MemoryAllocator* memory_allocator, GetContext* get_context) const {
const ImmutableOptions& ioptions = rep_->ioptions;
const uint32_t format_version = rep_->table_options.format_version;
assert(out_parsed_block);
assert(out_parsed_block->IsEmpty());
Status s;
Statistics* statistics = ioptions.stats;
std::unique_ptr<TBlocklike> block_holder;
if (block_comp_type != kNoCompression &&
uncompressed_block_contents.data.empty()) {
assert(compressed_block_contents.data.data());
// Retrieve the uncompressed contents into a new buffer
UncompressionContext context(block_comp_type);
UncompressionInfo info(context, uncompression_dict, block_comp_type);
s = UncompressBlockData(info, compressed_block_contents.data.data(),
compressed_block_contents.data.size(),
&uncompressed_block_contents, format_version,
ioptions, memory_allocator);
if (!s.ok()) {
return s;
}
}
rep_->create_context.Create(&block_holder,
std::move(uncompressed_block_contents));
// insert into uncompressed block cache
if (block_cache && block_holder->own_bytes()) {
size_t charge = block_holder->ApproximateMemoryUsage();
BlockCacheTypedHandle<TBlocklike>* cache_handle = nullptr;
s = block_cache.InsertFull(cache_key, block_holder.get(), charge,
&cache_handle, GetCachePriority<TBlocklike>(),
rep_->ioptions.lowest_used_cache_tier,
compressed_block_contents.data, block_comp_type);
if (s.ok()) {
assert(cache_handle != nullptr);
out_parsed_block->SetCachedValue(block_holder.release(),
block_cache.get(), cache_handle);
UpdateCacheInsertionMetrics(TBlocklike::kBlockType, get_context, charge,
s.IsOkOverwritten(), rep_->ioptions.stats);
} else {
RecordTick(statistics, BLOCK_CACHE_ADD_FAILURES);
}
} else {
out_parsed_block->SetOwnedValue(std::move(block_holder));
}
return s;
}
std::unique_ptr<FilterBlockReader> BlockBasedTable::CreateFilterBlockReader(
const ReadOptions& ro, 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, ro, prefetch_buffer, use_cache, prefetch, pin, lookup_context);
case Rep::FilterType::kFullFilter:
return FullFilterBlockReader::Create(this, ro, prefetch_buffer, use_cache,
prefetch, pin, lookup_context);
default:
// filter_type is either kNoFilter (exited the function at the first if),
// or it must be covered in this switch block
assert(false);
return std::unique_ptr<FilterBlockReader>();
}
}
// disable_prefix_seek should be set to true when prefix_extractor found in SST
// differs from the one in mutable_cf_options and index type is HashBasedIndex
InternalIteratorBase<IndexValue>* BlockBasedTable::NewIndexIterator(
const ReadOptions& read_options, bool disable_prefix_seek,
IndexBlockIter* input_iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) const {
assert(rep_ != nullptr);
assert(rep_->index_reader != nullptr);
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
return rep_->index_reader->NewIterator(read_options, disable_prefix_seek,
input_iter, get_context,
lookup_context);
}
// TODO?
template <>
DataBlockIter* BlockBasedTable::InitBlockIterator<DataBlockIter>(
const Rep* rep, Block* block, BlockType block_type,
DataBlockIter* input_iter, bool block_contents_pinned) {
return block->NewDataIterator(rep->internal_comparator.user_comparator(),
rep->get_global_seqno(block_type), input_iter,
rep->ioptions.stats, block_contents_pinned,
rep->user_defined_timestamps_persisted);
}
// TODO?
template <>
IndexBlockIter* BlockBasedTable::InitBlockIterator<IndexBlockIter>(
const Rep* rep, Block* block, BlockType block_type,
IndexBlockIter* input_iter, bool block_contents_pinned) {
return block->NewIndexIterator(
rep->internal_comparator.user_comparator(),
rep->get_global_seqno(block_type), input_iter, rep->ioptions.stats,
/* total_order_seek */ true, rep->index_has_first_key,
rep->index_key_includes_seq, rep->index_value_is_full,
block_contents_pinned, rep->user_defined_timestamps_persisted);
}
// Right now only called for Data blocks.
template <typename TBlocklike>
Status BlockBasedTable::LookupAndPinBlocksInCache(
const ReadOptions& ro, const BlockHandle& handle,
CachableEntry<TBlocklike>* out_parsed_block) const {
BlockCacheInterface<TBlocklike> block_cache{
rep_->table_options.block_cache.get()};
assert(block_cache);
Status s;
CachableEntry<UncompressionDict> uncompression_dict;
if (rep_->uncompression_dict_reader) {
const bool no_io = (ro.read_tier == kBlockCacheTier);
s = rep_->uncompression_dict_reader->GetOrReadUncompressionDictionary(
/* prefetch_buffer= */ nullptr, ro, no_io, ro.verify_checksums,
/* get_context= */ nullptr, /* lookup_context= */ nullptr,
&uncompression_dict);
if (!s.ok()) {
return s;
}
}
// Do the lookup.
CacheKey key_data = GetCacheKey(rep_->base_cache_key, handle);
const Slice key = key_data.AsSlice();
Statistics* statistics = rep_->ioptions.statistics.get();
BlockCreateContext create_ctx = rep_->create_context;
create_ctx.dict = uncompression_dict.GetValue()
? uncompression_dict.GetValue()
: &UncompressionDict::GetEmptyDict();
auto cache_handle =
block_cache.LookupFull(key, &create_ctx, GetCachePriority<TBlocklike>(),
statistics, rep_->ioptions.lowest_used_cache_tier);
if (!cache_handle) {
UpdateCacheMissMetrics(TBlocklike::kBlockType, /* get_context = */ nullptr);
return s;
}
// Found in Cache.
TBlocklike* value = block_cache.Value(cache_handle);
if (value) {
UpdateCacheHitMetrics(TBlocklike::kBlockType, /* get_context = */ nullptr,
block_cache.get()->GetUsage(cache_handle));
}
out_parsed_block->SetCachedValue(value, block_cache.get(), cache_handle);
assert(!out_parsed_block->IsEmpty());
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>
WithBlocklikeCheck<Status, TBlocklike>
BlockBasedTable::MaybeReadBlockAndLoadToCache(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
bool for_compaction, CachableEntry<TBlocklike>* out_parsed_block,
GetContext* get_context, BlockCacheLookupContext* lookup_context,
BlockContents* contents, bool async_read,
bool use_block_cache_for_lookup) const {
assert(out_parsed_block != nullptr);
const bool no_io = (ro.read_tier == kBlockCacheTier);
BlockCacheInterface<TBlocklike> block_cache{
rep_->table_options.block_cache.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;
CacheKey key_data;
Slice key;
bool is_cache_hit = false;
if (block_cache) {
// create key for block cache
key_data = GetCacheKey(rep_->base_cache_key, handle);
key = key_data.AsSlice();
if (!contents) {
if (use_block_cache_for_lookup) {
s = GetDataBlockFromCache(key, block_cache, out_parsed_block,
get_context, &uncompression_dict);
// Value could still be null at this point, so check the cache handle
// and update the read pattern for prefetching
if (out_parsed_block->GetValue() ||
out_parsed_block->GetCacheHandle()) {
// TODO(haoyu): Differentiate cache hit on uncompressed block cache
// and compressed block cache.
is_cache_hit = true;
if (prefetch_buffer) {
// Update the block details so that PrefetchBuffer can use the read
// pattern to determine if reads are sequential or not for
// prefetching. It should also take in account blocks read from
// cache.
prefetch_buffer->UpdateReadPattern(
handle.offset(), BlockSizeWithTrailer(handle),
ro.adaptive_readahead /*decrease_readahead_size*/);
}
}
}
}
// Can't find the block from the cache. If I/O is allowed, read from the
// file.
if (out_parsed_block->GetValue() == nullptr &&
out_parsed_block->GetCacheHandle() == nullptr && !no_io &&
ro.fill_cache) {
Statistics* statistics = rep_->ioptions.stats;
const bool maybe_compressed =
TBlocklike::kBlockType != BlockType::kFilter &&
TBlocklike::kBlockType != BlockType::kCompressionDictionary &&
rep_->blocks_maybe_compressed;
// This flag, if true, tells BlockFetcher to return the uncompressed
// block when ReadBlockContents() is called.
const bool do_uncompress = maybe_compressed;
CompressionType contents_comp_type;
// Maybe serialized or uncompressed
BlockContents tmp_contents;
BlockContents uncomp_contents;
BlockContents comp_contents;
if (!contents) {
Histograms histogram = for_compaction ? READ_BLOCK_COMPACTION_MICROS
: READ_BLOCK_GET_MICROS;
StopWatch sw(rep_->ioptions.clock, statistics, histogram);
// Setting do_uncompress to false may cause an extra mempcy in the
// following cases -
// 1. Compression is enabled, but block is not actually compressed
// 2. Compressed block is in the prefetch buffer
// 3. Direct IO
//
// It would also cause a memory allocation to be used rather than
// stack if the compressed block size is < 5KB
BlockFetcher block_fetcher(
rep_->file.get(), prefetch_buffer, rep_->footer, ro, handle,
&tmp_contents, rep_->ioptions, do_uncompress, maybe_compressed,
TBlocklike::kBlockType, uncompression_dict,
rep_->persistent_cache_options,
GetMemoryAllocator(rep_->table_options),
/*allocator=*/nullptr);
// If prefetch_buffer is not allocated, it will fallback to synchronous
// reading of block contents.
if (async_read && prefetch_buffer != nullptr) {
s = block_fetcher.ReadAsyncBlockContents();
if (!s.ok()) {
return s;
}
} else {
s = block_fetcher.ReadBlockContents();
}
contents_comp_type = block_fetcher.get_compression_type();
if (get_context) {
switch (TBlocklike::kBlockType) {
case BlockType::kIndex:
++get_context->get_context_stats_.num_index_read;
break;
case BlockType::kFilter:
case BlockType::kFilterPartitionIndex:
++get_context->get_context_stats_.num_filter_read;
break;
default:
break;
}
}
if (s.ok()) {
if (do_uncompress && contents_comp_type != kNoCompression) {
comp_contents = BlockContents(block_fetcher.GetCompressedBlock());
uncomp_contents = std::move(tmp_contents);
} else if (contents_comp_type != kNoCompression) {
// do_uncompress must be false, so output of BlockFetcher is
// compressed
comp_contents = std::move(tmp_contents);
} else {
uncomp_contents = std::move(tmp_contents);
}
// If filling cache is allowed and a cache is configured, try to put
// the block to the cache. Do this here while block_fetcher is in
// scope, since comp_contents will be a reference to the compressed
// block in block_fetcher
s = PutDataBlockToCache(
key, block_cache, out_parsed_block, std::move(uncomp_contents),
std::move(comp_contents), contents_comp_type, uncompression_dict,
GetMemoryAllocator(rep_->table_options), get_context);
}
} else {
contents_comp_type = GetBlockCompressionType(*contents);
if (contents_comp_type != kNoCompression) {
comp_contents = std::move(*contents);
} else {
uncomp_contents = std::move(*contents);
}
if (s.ok()) {
// If filling cache is allowed and a cache is configured, try to put
// the block to the cache.
s = PutDataBlockToCache(
key, block_cache, out_parsed_block, std::move(uncomp_contents),
std::move(comp_contents), contents_comp_type, uncompression_dict,
GetMemoryAllocator(rep_->table_options), get_context);
}
}
}
}
// TODO: optimize so that lookup_context != nullptr implies the others
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled() &&
lookup_context) {
SaveLookupContextOrTraceRecord(
key, is_cache_hit, ro, out_parsed_block->GetValue(), lookup_context);
}
assert(s.ok() || out_parsed_block->GetValue() == nullptr);
return s;
}
template <typename TBlocklike>
WithBlocklikeCheck<void, TBlocklike>
BlockBasedTable::SaveLookupContextOrTraceRecord(
const Slice& block_key, bool is_cache_hit, const ReadOptions& ro,
const TBlocklike* parsed_block_value,
BlockCacheLookupContext* lookup_context) const {
assert(lookup_context);
size_t usage = 0;
uint64_t nkeys = 0;
if (parsed_block_value) {
// Approximate the number of keys in the block using restarts.
int interval = rep_->table_options.block_restart_interval;
nkeys = interval * GetBlockNumRestarts(*parsed_block_value);
// On average, the last restart should be just over half utilized.
// Specifically, 1..N should be N/2 + 0.5. For example, 7 -> 4, 8 -> 4.5.
// Use the get_id to alternate between rounding up vs. down.
if (nkeys > 0) {
bool rounding = static_cast<int>(lookup_context->get_id) & 1;
nkeys -= (interval - rounding) / 2;
}
usage = parsed_block_value->ApproximateMemoryUsage();
}
TraceType trace_block_type = TraceType::kTraceMax;
switch (TBlocklike::kBlockType) {
case BlockType::kData:
trace_block_type = TraceType::kBlockTraceDataBlock;
break;
case BlockType::kFilter:
case BlockType::kFilterPartitionIndex:
trace_block_type = TraceType::kBlockTraceFilterBlock;
break;
case BlockType::kCompressionDictionary:
trace_block_type = TraceType::kBlockTraceUncompressionDictBlock;
break;
case BlockType::kRangeDeletion:
trace_block_type = TraceType::kBlockTraceRangeDeletionBlock;
break;
case BlockType::kIndex:
trace_block_type = TraceType::kBlockTraceIndexBlock;
break;
default:
// This cannot happen.
assert(false);
break;
}
const bool no_io = ro.read_tier == kBlockCacheTier;
bool no_insert = no_io || !ro.fill_cache;
if (BlockCacheTraceHelper::IsGetOrMultiGetOnDataBlock(
trace_block_type, lookup_context->caller)) {
// 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.ToString(), nkeys);
// Defer logging the access to Get() and MultiGet() to trace additional
// information, e.g., referenced_key
} else {
// Avoid making copy of block_key if it doesn't need to be saved in
// BlockCacheLookupContext
lookup_context->FillLookupContext(is_cache_hit, no_insert, trace_block_type,
/*block_size=*/usage,
/*block_key=*/{}, nkeys);
// Fill in default values for irrelevant/unknown fields
FinishTraceRecord(*lookup_context, block_key,
lookup_context->referenced_key,
/*does_referenced_key_exist*/ false,
/*referenced_data_size*/ 0);
}
}
void BlockBasedTable::FinishTraceRecord(
const BlockCacheLookupContext& lookup_context, const Slice& block_key,
const Slice& referenced_key, bool does_referenced_key_exist,
uint64_t referenced_data_size) const {
// Avoid making copy of referenced_key if it doesn't need to be saved in
// BlockCacheLookupContext
BlockCacheTraceRecord access_record(
rep_->ioptions.clock->NowMicros(),
/*block_key=*/"", lookup_context.block_type, lookup_context.block_size,
rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(), rep_->sst_number_for_tracing(),
lookup_context.caller, lookup_context.is_cache_hit,
lookup_context.no_insert, lookup_context.get_id,
lookup_context.get_from_user_specified_snapshot,
/*referenced_key=*/"", referenced_data_size,
lookup_context.num_keys_in_block, does_referenced_key_exist);
// TODO: Should handle status here?
block_cache_tracer_
->WriteBlockAccess(access_record, block_key, rep_->cf_name_for_tracing(),
referenced_key)
.PermitUncheckedError();
}
template <typename TBlocklike /*, auto*/>
WithBlocklikeCheck<Status, TBlocklike> BlockBasedTable::RetrieveBlock(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<TBlocklike>* out_parsed_block, GetContext* get_context,
BlockCacheLookupContext* lookup_context, bool for_compaction,
bool use_cache, bool async_read, bool use_block_cache_for_lookup) const {
assert(out_parsed_block);
assert(out_parsed_block->IsEmpty());
Status s;
if (use_cache) {
s = MaybeReadBlockAndLoadToCache(
prefetch_buffer, ro, handle, uncompression_dict, for_compaction,
out_parsed_block, get_context, lookup_context,
/*contents=*/nullptr, async_read, use_block_cache_for_lookup);
if (!s.ok()) {
return s;
}
if (out_parsed_block->GetValue() != nullptr ||
out_parsed_block->GetCacheHandle() != nullptr) {
assert(s.ok());
return s;
}
}
assert(out_parsed_block->IsEmpty());
const bool no_io = ro.read_tier == kBlockCacheTier;
if (no_io) {
return Status::Incomplete("no blocking io");
}
const bool maybe_compressed =
TBlocklike::kBlockType != BlockType::kFilter &&
TBlocklike::kBlockType != BlockType::kCompressionDictionary &&
rep_->blocks_maybe_compressed;
std::unique_ptr<TBlocklike> block;
{
Histograms histogram =
for_compaction ? READ_BLOCK_COMPACTION_MICROS : READ_BLOCK_GET_MICROS;
StopWatch sw(rep_->ioptions.clock, rep_->ioptions.stats, histogram);
s = ReadAndParseBlockFromFile(
rep_->file.get(), prefetch_buffer, rep_->footer, ro, handle, &block,
rep_->ioptions, rep_->create_context, maybe_compressed,
uncompression_dict, rep_->persistent_cache_options,
GetMemoryAllocator(rep_->table_options), for_compaction, async_read);
if (get_context) {
switch (TBlocklike::kBlockType) {
case BlockType::kIndex:
++(get_context->get_context_stats_.num_index_read);
break;
case BlockType::kFilter:
case BlockType::kFilterPartitionIndex:
++(get_context->get_context_stats_.num_filter_read);
break;
default:
break;
}
}
}
if (!s.ok()) {
return s;
}
out_parsed_block->SetOwnedValue(std::move(block));
assert(s.ok());
return s;
}
BlockBasedTable::PartitionedIndexIteratorState::PartitionedIndexIteratorState(
const BlockBasedTable* table,
UnorderedMap<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());
// block_map_ must be exhaustive
if (block == block_map_->end()) {
assert(false);
// Signal problem to caller
return nullptr;
}
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.user_comparator(),
rep->get_global_seqno(BlockType::kIndex), nullptr, kNullStats, true,
rep->index_has_first_key, rep->index_key_includes_seq,
rep->index_value_is_full, /*block_contents_pinned=*/false,
rep->user_defined_timestamps_persisted);
}
// 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
//
// If read_options.read_tier == kBlockCacheTier, this method will do no I/O and
// will return true if the filter block is not in memory and not found in block
// cache.
//
// REQUIRES: this method shouldn't be called while the DB lock is held.
bool BlockBasedTable::PrefixRangeMayMatch(
const Slice& internal_key, const ReadOptions& read_options,
const SliceTransform* options_prefix_extractor,
const bool need_upper_bound_check, BlockCacheLookupContext* lookup_context,
bool* filter_checked) 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 ts_sz = rep_->internal_comparator.user_comparator()->timestamp_size();
auto user_key_without_ts =
ExtractUserKeyAndStripTimestamp(internal_key, ts_sz);
if (!prefix_extractor->InDomain(user_key_without_ts)) {
return true;
}
bool may_match = true;
FilterBlockReader* const filter = rep_->filter.get();
*filter_checked = false;
if (filter != nullptr) {
const bool no_io = read_options.read_tier == kBlockCacheTier;
const Slice* const const_ikey_ptr = &internal_key;
may_match = filter->RangeMayExist(
read_options.iterate_upper_bound, user_key_without_ts, prefix_extractor,
rep_->internal_comparator.user_comparator(), const_ikey_ptr,
filter_checked, need_upper_bound_check, no_io, lookup_context,
read_options);
}
return may_match;
}
bool BlockBasedTable::PrefixExtractorChanged(
const SliceTransform* prefix_extractor) const {
if (prefix_extractor == nullptr) {
return true;
} else if (prefix_extractor == rep_->table_prefix_extractor.get()) {
return false;
} else {
return PrefixExtractorChangedHelper(rep_->table_properties.get(),
prefix_extractor);
}
}
Statistics* BlockBasedTable::GetStatistics() const {
return rep_->ioptions.stats;
}
bool BlockBasedTable::IsLastLevel() const {
return rep_->level == rep_->ioptions.num_levels - 1;
}
InternalIterator* BlockBasedTable::NewIterator(
const ReadOptions& read_options, const SliceTransform* prefix_extractor,
Arena* arena, bool skip_filters, TableReaderCaller caller,
size_t compaction_readahead_size, bool allow_unprepared_value) {
BlockCacheLookupContext lookup_context{caller};
bool need_upper_bound_check =
read_options.auto_prefix_mode || PrefixExtractorChanged(prefix_extractor);
std::unique_ptr<InternalIteratorBase<IndexValue>> index_iter(NewIndexIterator(
read_options,
/*disable_prefix_seek=*/need_upper_bound_check &&
rep_->index_type == BlockBasedTableOptions::kHashSearch,
/*input_iter=*/nullptr, /*get_context=*/nullptr, &lookup_context));
if (arena == nullptr) {
return new BlockBasedTableIterator(
this, read_options, rep_->internal_comparator, std::move(index_iter),
!skip_filters && !read_options.total_order_seek &&
prefix_extractor != nullptr,
need_upper_bound_check, prefix_extractor, caller,
compaction_readahead_size, allow_unprepared_value);
} else {
auto* mem = arena->AllocateAligned(sizeof(BlockBasedTableIterator));
return new (mem) BlockBasedTableIterator(
this, read_options, rep_->internal_comparator, std::move(index_iter),
!skip_filters && !read_options.total_order_seek &&
prefix_extractor != nullptr,
need_upper_bound_check, prefix_extractor, caller,
compaction_readahead_size, allow_unprepared_value);
}
}
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, read_options.timestamp);
}
FragmentedRangeTombstoneIterator* BlockBasedTable::NewRangeTombstoneIterator(
SequenceNumber read_seqno, const Slice* timestamp) {
if (rep_->fragmented_range_dels == nullptr) {
return nullptr;
}
return new FragmentedRangeTombstoneIterator(rep_->fragmented_range_dels,
rep_->internal_comparator,
read_seqno, timestamp);
}
bool BlockBasedTable::FullFilterKeyMayMatch(
FilterBlockReader* filter, const Slice& internal_key, const bool no_io,
const SliceTransform* prefix_extractor, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
const ReadOptions& read_options) const {
if (filter == nullptr) {
return true;
}
Slice user_key = ExtractUserKey(internal_key);
const Slice* const const_ikey_ptr = &internal_key;
bool may_match = true;
size_t ts_sz = rep_->internal_comparator.user_comparator()->timestamp_size();
Slice user_key_without_ts = StripTimestampFromUserKey(user_key, ts_sz);
if (rep_->whole_key_filtering) {
may_match = filter->KeyMayMatch(user_key_without_ts, no_io, const_ikey_ptr,
get_context, lookup_context, read_options);
if (may_match) {
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_FULL_POSITIVE);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_positive, 1, rep_->level);
} else {
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_USEFUL);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, 1, rep_->level);
}
} else if (!PrefixExtractorChanged(prefix_extractor) &&
prefix_extractor->InDomain(user_key_without_ts)) {
// FIXME ^^^: there should be no reason for Get() to depend on current
// prefix_extractor at all. It should always use table_prefix_extractor.
may_match = filter->PrefixMayMatch(
prefix_extractor->Transform(user_key_without_ts), no_io, const_ikey_ptr,
get_context, lookup_context, read_options);
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_PREFIX_CHECKED);
if (may_match) {
// Includes prefix stats
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_positive, 1, rep_->level);
} else {
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_PREFIX_USEFUL);
// Includes prefix stats
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, 1, rep_->level);
}
}
return may_match;
}
void BlockBasedTable::FullFilterKeysMayMatch(
FilterBlockReader* filter, MultiGetRange* range, const bool no_io,
const SliceTransform* prefix_extractor,
BlockCacheLookupContext* lookup_context,
const ReadOptions& read_options) const {
if (filter == nullptr) {
return;
}
uint64_t before_keys = range->KeysLeft();
assert(before_keys > 0); // Caller should ensure
if (rep_->whole_key_filtering) {
filter->KeysMayMatch(range, no_io, lookup_context, read_options);
uint64_t after_keys = range->KeysLeft();
if (after_keys) {
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_FULL_POSITIVE, after_keys);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_positive, after_keys,
rep_->level);
}
uint64_t filtered_keys = before_keys - after_keys;
if (filtered_keys) {
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_USEFUL, filtered_keys);
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, filtered_keys,
rep_->level);
}
} else if (!PrefixExtractorChanged(prefix_extractor)) {
// FIXME ^^^: there should be no reason for MultiGet() to depend on current
// prefix_extractor at all. It should always use table_prefix_extractor.
filter->PrefixesMayMatch(range, prefix_extractor, false, lookup_context,
read_options);
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_PREFIX_CHECKED, before_keys);
uint64_t after_keys = range->KeysLeft();
if (after_keys) {
// Includes prefix stats
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_positive, after_keys,
rep_->level);
}
uint64_t filtered_keys = before_keys - after_keys;
if (filtered_keys) {
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_PREFIX_USEFUL,
filtered_keys);
// Includes prefix stats
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, filtered_keys,
rep_->level);
}
}
}
Status BlockBasedTable::ApproximateKeyAnchors(const ReadOptions& read_options,
std::vector<Anchor>& anchors) {
// We iterator the whole index block here. More efficient implementation
// is possible if we push this operation into IndexReader. For example, we
// can directly sample from restart block entries in the index block and
// only read keys needed. Here we take a simple solution. Performance is
// likely not to be a problem. We are compacting the whole file, so all
// keys will be read out anyway. An extra read to index block might be
// a small share of the overhead. We can try to optimize if needed.
//
// `CacheDependencies()` brings all the blocks into cache using one I/O. That
// way the full index scan usually finds the index data it is looking for in
// cache rather than doing an I/O for each "dependency" (partition).
Status s = rep_->index_reader->CacheDependencies(
read_options, false /* pin */, nullptr /* prefetch_buffer */);
if (!s.ok()) {
return s;
}
IndexBlockIter iiter_on_stack;
auto iiter = NewIndexIterator(
read_options, /*disable_prefix_seek=*/false, &iiter_on_stack,
/*get_context=*/nullptr, /*lookup_context=*/nullptr);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr.reset(iiter);
}
// If needed the threshold could be more adaptive. For example, it can be
// based on size, so that a larger will be sampled to more partitions than a
// smaller file. The size might also need to be passed in by the caller based
// on total compaction size.
const uint64_t kMaxNumAnchors = uint64_t{128};
uint64_t num_blocks = this->GetTableProperties()->num_data_blocks;
uint64_t num_blocks_per_anchor = num_blocks / kMaxNumAnchors;
if (num_blocks_per_anchor == 0) {
num_blocks_per_anchor = 1;
}
uint64_t count = 0;
std::string last_key;
uint64_t range_size = 0;
uint64_t prev_offset = 0;
for (iiter->SeekToFirst(); iiter->Valid(); iiter->Next()) {
const BlockHandle& bh = iiter->value().handle;
range_size += bh.offset() + bh.size() - prev_offset;
prev_offset = bh.offset() + bh.size();
if (++count % num_blocks_per_anchor == 0) {
count = 0;
anchors.emplace_back(iiter->user_key(), range_size);
range_size = 0;
} else {
last_key = iiter->user_key().ToString();
}
}
if (count != 0) {
anchors.emplace_back(last_key, range_size);
}
return Status::OK();
}
bool BlockBasedTable::TimestampMayMatch(const ReadOptions& read_options) const {
if (read_options.timestamp != nullptr && !rep_->min_timestamp.empty()) {
RecordTick(rep_->ioptions.stats, TIMESTAMP_FILTER_TABLE_CHECKED);
auto read_ts = read_options.timestamp;
auto comparator = rep_->internal_comparator.user_comparator();
if (comparator->CompareTimestamp(*read_ts, rep_->min_timestamp) < 0) {
RecordTick(rep_->ioptions.stats, TIMESTAMP_FILTER_TABLE_FILTERED);
return false;
}
}
return true;
}
Status BlockBasedTable::Get(const ReadOptions& read_options, const Slice& key,
GetContext* get_context,
const SliceTransform* prefix_extractor,
bool skip_filters) {
// Similar to Bloom filter !may_match
// If timestamp is beyond the range of the table, skip
if (!TimestampMayMatch(read_options)) {
return Status::OK();
}
assert(key.size() >= 8); // key must be internal key
assert(get_context != nullptr);
Status s;
const bool no_io = read_options.read_tier == kBlockCacheTier;
FilterBlockReader* const filter =
!skip_filters ? rep_->filter.get() : nullptr;
// First check the full filter
// If full filter not useful, Then go into each block
uint64_t tracing_get_id = get_context->get_tracing_get_id();
BlockCacheLookupContext lookup_context{
TableReaderCaller::kUserGet, tracing_get_id,
/*get_from_user_specified_snapshot=*/read_options.snapshot != nullptr};
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled()) {
// Trace the key since it contains both user key and sequence number.
lookup_context.referenced_key = key.ToString();
lookup_context.get_from_user_specified_snapshot =
read_options.snapshot != nullptr;
}
TEST_SYNC_POINT("BlockBasedTable::Get:BeforeFilterMatch");
const bool may_match =
FullFilterKeyMayMatch(filter, key, no_io, prefix_extractor, get_context,
&lookup_context, read_options);
TEST_SYNC_POINT("BlockBasedTable::Get:AfterFilterMatch");
if (may_match) {
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(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 matched a key in SST
bool done = false;
for (iiter->Seek(key); iiter->Valid() && !done; iiter->Next()) {
IndexValue v = iiter->value();
if (!v.first_internal_key.empty() && !skip_filters &&
UserComparatorWrapper(rep_->internal_comparator.user_comparator())
.CompareWithoutTimestamp(
ExtractUserKey(key),
ExtractUserKey(v.first_internal_key)) < 0) {
// The requested key falls between highest key in previous block and
// lowest key in current block.
break;
}
BlockCacheLookupContext lookup_data_block_context{
TableReaderCaller::kUserGet, tracing_get_id,
/*get_from_user_specified_snapshot=*/read_options.snapshot !=
nullptr};
bool does_referenced_key_exist = false;
DataBlockIter biter;
uint64_t referenced_data_size = 0;
Status tmp_status;
NewDataBlockIterator<DataBlockIter>(
read_options, v.handle, &biter, BlockType::kData, get_context,
&lookup_data_block_context, /*prefetch_buffer=*/nullptr,
/*for_compaction=*/false, /*async_read=*/false, tmp_status,
/*use_block_cache_for_lookup=*/true);
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();
s = biter.status();
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;
Status pik_status = ParseInternalKey(
biter.key(), &parsed_key, false /* log_err_key */); // TODO
if (!pik_status.ok()) {
s = pik_status;
}
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();
if (!s.ok()) {
break;
}
}
// Write the block cache access record.
if (block_cache_tracer_ && block_cache_tracer_->is_tracing_enabled()) {
// Avoid making copy of block_key, cf_name, and referenced_key when
// constructing the access record.
Slice referenced_key;
if (does_referenced_key_exist) {
referenced_key = biter.key();
} else {
referenced_key = key;
}
FinishTraceRecord(lookup_data_block_context,
lookup_data_block_context.block_key, referenced_key,
does_referenced_key_exist, referenced_data_size);
}
if (done) {
// Avoid the extra Next which is expensive in two-level indexes
break;
}
}
if (matched && filter != nullptr) {
if (rep_->whole_key_filtering) {
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_FULL_TRUE_POSITIVE);
} else {
RecordTick(rep_->ioptions.stats, BLOOM_FILTER_PREFIX_TRUE_POSITIVE);
}
// Includes prefix stats
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_full_true_positive, 1,
rep_->level);
}
if (s.ok() && !iiter->status().IsNotFound()) {
s = iiter->status();
}
}
return s;
}
Status BlockBasedTable::MultiGetFilter(const ReadOptions& read_options,
const SliceTransform* prefix_extractor,
MultiGetRange* mget_range) {
if (mget_range->empty()) {
// Caller should ensure non-empty (performance bug)
assert(false);
return Status::OK(); // Nothing to do
}
FilterBlockReader* const filter = rep_->filter.get();
if (!filter) {
return Status::OK();
}
// 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 (mget_range->begin()->get_context) {
tracing_mget_id = mget_range->begin()->get_context->get_tracing_get_id();
}
BlockCacheLookupContext lookup_context{
TableReaderCaller::kUserMultiGet, tracing_mget_id,
/*_get_from_user_specified_snapshot=*/read_options.snapshot != nullptr};
FullFilterKeysMayMatch(filter, mget_range, no_io, prefix_extractor,
&lookup_context, read_options);
return Status::OK();
}
Status BlockBasedTable::Prefetch(const ReadOptions& read_options,
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(read_options, /*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;
Status tmp_status;
NewDataBlockIterator<DataBlockIter>(
read_options, block_handle, &biter, /*type=*/BlockType::kData,
/*get_context=*/nullptr, &lookup_context,
/*prefetch_buffer=*/nullptr, /*for_compaction=*/false,
/*async_read=*/false, tmp_status, /*use_block_cache_for_lookup=*/true);
if (!biter.status().ok()) {
// there was an unexpected error while pre-fetching
return biter.status();
}
}
return Status::OK();
}
Status BlockBasedTable::VerifyChecksum(const ReadOptions& read_options,
TableReaderCaller caller) {
Status s;
// Check Meta blocks
std::unique_ptr<Block> metaindex;
std::unique_ptr<InternalIterator> metaindex_iter;
s = ReadMetaIndexBlock(read_options, nullptr /* prefetch buffer */,
&metaindex, &metaindex_iter);
if (s.ok()) {
s = VerifyChecksumInMetaBlocks(read_options, metaindex_iter.get());
if (!s.ok()) {
return s;
}
} else {
return s;
}
// Check Data blocks
IndexBlockIter iiter_on_stack;
BlockCacheLookupContext context{caller};
InternalIteratorBase<IndexValue>* iiter = NewIndexIterator(
read_options, /*disable_prefix_seek=*/false, &iiter_on_stack,
/*get_context=*/nullptr, &context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (iiter != &iiter_on_stack) {
iiter_unique_ptr = std::unique_ptr<InternalIteratorBase<IndexValue>>(iiter);
}
if (!iiter->status().ok()) {
// error opening index iterator
return iiter->status();
}
s = VerifyChecksumInBlocks(read_options, iiter);
return s;
}
Status BlockBasedTable::VerifyChecksumInBlocks(
const ReadOptions& read_options,
InternalIteratorBase<IndexValue>* index_iter) {
Status s;
// We are scanning the whole file, so no need to do exponential
// increasing of the buffer size.
size_t readahead_size = (read_options.readahead_size != 0)
? read_options.readahead_size
: rep_->table_options.max_auto_readahead_size;
// FilePrefetchBuffer doesn't work in mmap mode and readahead is not
// needed there.
FilePrefetchBuffer prefetch_buffer(
readahead_size /* readahead_size */,
readahead_size /* max_readahead_size */,
!rep_->ioptions.allow_mmap_reads /* enable */);
for (index_iter->SeekToFirst(); index_iter->Valid(); index_iter->Next()) {
s = index_iter->status();
if (!s.ok()) {
break;
}
BlockHandle handle = index_iter->value().handle;
BlockContents contents;
BlockFetcher block_fetcher(
rep_->file.get(), &prefetch_buffer, rep_->footer, read_options, 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;
}
}
if (s.ok()) {
// In the case of two level indexes, we would have exited the above loop
// by checking index_iter->Valid(), but Valid() might have returned false
// due to an IO error. So check the index_iter status
s = index_iter->status();
}
return s;
}
BlockType BlockBasedTable::GetBlockTypeForMetaBlockByName(
const Slice& meta_block_name) {
if (meta_block_name.starts_with(kFullFilterBlockPrefix)) {
return BlockType::kFilter;
}
if (meta_block_name.starts_with(kPartitionedFilterBlockPrefix)) {
return BlockType::kFilterPartitionIndex;
}
if (meta_block_name == kPropertiesBlockName) {
return BlockType::kProperties;
}
if (meta_block_name == kCompressionDictBlockName) {
return BlockType::kCompressionDictionary;
}
if (meta_block_name == kRangeDelBlockName) {
return BlockType::kRangeDeletion;
}
if (meta_block_name == kHashIndexPrefixesBlock) {
return BlockType::kHashIndexPrefixes;
}
if (meta_block_name == kHashIndexPrefixesMetadataBlock) {
return BlockType::kHashIndexMetadata;
}
if (meta_block_name == kIndexBlockName) {
return BlockType::kIndex;
}
if (meta_block_name.starts_with(kObsoleteFilterBlockPrefix)) {
// Obsolete but possible in old files
return BlockType::kInvalid;
}
assert(false);
return BlockType::kInvalid;
}
Status BlockBasedTable::VerifyChecksumInMetaBlocks(
const ReadOptions& read_options, 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);
if (!s.ok()) {
break;
}
BlockContents contents;
const Slice meta_block_name = index_iter->key();
if (meta_block_name == kPropertiesBlockName) {
// Unfortunate special handling for properties block checksum w/
// global seqno
std::unique_ptr<TableProperties> table_properties;
s = ReadTablePropertiesHelper(read_options, handle, rep_->file.get(),
nullptr /* prefetch_buffer */, rep_->footer,
rep_->ioptions, &table_properties,
nullptr /* memory_allocator */);
} else if (rep_->verify_checksum_set_on_open &&
meta_block_name == kIndexBlockName) {
// WART: For now, to maintain similar I/O behavior as before
// format_version=6, we skip verifying index block checksum--but only
// if it was checked on open.
} else {
// FIXME? Need to verify checksums of index and filter partitions?
s = BlockFetcher(
rep_->file.get(), nullptr /* prefetch buffer */, rep_->footer,
read_options, handle, &contents, rep_->ioptions,
false /* decompress */, false /*maybe_compressed*/,
GetBlockTypeForMetaBlockByName(meta_block_name),
UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options)
.ReadBlockContents();
}
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;
}
CacheKey key = GetCacheKey(rep_->base_cache_key, handle);
Cache::Handle* const cache_handle = cache->Lookup(key.AsSlice());
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->status().ok());
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(
const ReadOptions& ro, FilePrefetchBuffer* prefetch_buffer,
InternalIterator* meta_iter, bool use_cache, bool prefetch, bool pin,
BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
if (FormatVersionUsesIndexHandleInFooter(rep_->footer.format_version())) {
rep_->index_handle = rep_->footer.index_handle();
} else {
Status s = FindMetaBlock(meta_iter, kIndexBlockName, &rep_->index_handle);
if (!s.ok()) {
return s;
}
}
switch (rep_->index_type) {
case BlockBasedTableOptions::kTwoLevelIndexSearch: {
return PartitionIndexReader::Create(this, ro, prefetch_buffer, use_cache,
prefetch, pin, lookup_context,
index_reader);
}
case BlockBasedTableOptions::kBinarySearch:
FALLTHROUGH_INTENDED;
case BlockBasedTableOptions::kBinarySearchWithFirstKey: {
return BinarySearchIndexReader::Create(this, ro, prefetch_buffer,
use_cache, prefetch, pin,
lookup_context, index_reader);
}
case BlockBasedTableOptions::kHashSearch: {
if (!rep_->table_prefix_extractor) {
ROCKS_LOG_WARN(rep_->ioptions.logger,
"Missing prefix extractor for hash index. Fall back to"
" binary search index.");
return BinarySearchIndexReader::Create(this, ro, prefetch_buffer,
use_cache, prefetch, pin,
lookup_context, index_reader);
} else {
return HashIndexReader::Create(this, ro, prefetch_buffer, meta_iter,
use_cache, prefetch, pin, lookup_context,
index_reader);
}
}
default: {
std::string error_message =
"Unrecognized index type: " + std::to_string(rep_->index_type);
return Status::InvalidArgument(error_message.c_str());
}
}
}
uint64_t BlockBasedTable::ApproximateDataOffsetOf(
const InternalIteratorBase<IndexValue>& index_iter,
uint64_t data_size) const {
assert(index_iter.status().ok());
if (index_iter.Valid()) {
BlockHandle handle = index_iter.value().handle;
return handle.offset();
} else {
// The iterator is past the last key in the file.
return data_size;
}
}
uint64_t BlockBasedTable::GetApproximateDataSize() {
// Should be in table properties unless super old version
if (rep_->table_properties) {
return rep_->table_properties->data_size;
}
// Fall back to rough estimate from footer
return rep_->footer.metaindex_handle().offset();
}
uint64_t BlockBasedTable::ApproximateOffsetOf(const ReadOptions& read_options,
const Slice& key,
TableReaderCaller caller) {
uint64_t data_size = GetApproximateDataSize();
if (UNLIKELY(data_size == 0)) {
// Hmm. Let's just split in half to avoid skewing one way or another,
// since we don't know whether we're operating on lower bound or
// upper bound.
return rep_->file_size / 2;
}
BlockCacheLookupContext context(caller);
IndexBlockIter iiter_on_stack;
ReadOptions ro;
ro.total_order_seek = true;
ro.io_activity = read_options.io_activity;
auto index_iter =
NewIndexIterator(ro, /*disable_prefix_seek=*/true,
/*input_iter=*/&iiter_on_stack, /*get_context=*/nullptr,
/*lookup_context=*/&context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (index_iter != &iiter_on_stack) {
iiter_unique_ptr.reset(index_iter);
}
index_iter->Seek(key);
uint64_t offset;
if (index_iter->status().ok()) {
offset = ApproximateDataOffsetOf(*index_iter, data_size);
} else {
// Split in half to avoid skewing one way or another,
// since we don't know whether we're operating on lower bound or
// upper bound.
return rep_->file_size / 2;
}
// Pro-rate file metadata (incl filters) size-proportionally across data
// blocks.
double size_ratio =
static_cast<double>(offset) / static_cast<double>(data_size);
return static_cast<uint64_t>(size_ratio *
static_cast<double>(rep_->file_size));
}
uint64_t BlockBasedTable::ApproximateSize(const ReadOptions& read_options,
const Slice& start, const Slice& end,
TableReaderCaller caller) {
assert(rep_->internal_comparator.Compare(start, end) <= 0);
uint64_t data_size = GetApproximateDataSize();
if (UNLIKELY(data_size == 0)) {
// Hmm. Assume whole file is involved, since we have lower and upper
// bound. This likely skews the estimate if we consider that this function
// is typically called with `[start, end]` fully contained in the file's
// key-range.
return rep_->file_size;
}
BlockCacheLookupContext context(caller);
IndexBlockIter iiter_on_stack;
ReadOptions ro;
ro.total_order_seek = true;
ro.io_activity = read_options.io_activity;
auto index_iter =
NewIndexIterator(ro, /*disable_prefix_seek=*/true,
/*input_iter=*/&iiter_on_stack, /*get_context=*/nullptr,
/*lookup_context=*/&context);
std::unique_ptr<InternalIteratorBase<IndexValue>> iiter_unique_ptr;
if (index_iter != &iiter_on_stack) {
iiter_unique_ptr.reset(index_iter);
}
index_iter->Seek(start);
uint64_t start_offset;
if (index_iter->status().ok()) {
start_offset = ApproximateDataOffsetOf(*index_iter, data_size);
} else {
// Assume file is involved from the start. This likely skews the estimate
// but is consistent with the above error handling.
start_offset = 0;
}
index_iter->Seek(end);
uint64_t end_offset;
if (index_iter->status().ok()) {
end_offset = ApproximateDataOffsetOf(*index_iter, data_size);
} else {
// Assume file is involved until the end. This likely skews the estimate
// but is consistent with the above error handling.
end_offset = data_size;
}
assert(end_offset >= start_offset);
// Pro-rate file metadata (incl filters) size-proportionally across data
// blocks.
double size_ratio = static_cast<double>(end_offset - start_offset) /
static_cast<double>(data_size);
return static_cast<uint64_t>(size_ratio *
static_cast<double>(rep_->file_size));
}
bool BlockBasedTable::TEST_FilterBlockInCache() const {
assert(rep_ != nullptr);
return rep_->filter_type != Rep::FilterType::kNoFilter &&
TEST_BlockInCache(rep_->filter_handle);
}
bool BlockBasedTable::TEST_IndexBlockInCache() const {
assert(rep_ != nullptr);
return TEST_BlockInCache(rep_->index_handle);
}
Status BlockBasedTable::GetKVPairsFromDataBlocks(
const ReadOptions& read_options, std::vector<KVPairBlock>* kv_pair_blocks) {
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(read_options, /*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;
Status tmp_status;
datablock_iter.reset(NewDataBlockIterator<DataBlockIter>(
read_options, blockhandles_iter->value().handle,
/*input_iter=*/nullptr, /*type=*/BlockType::kData,
/*get_context=*/nullptr, /*lookup_context=*/nullptr,
/*prefetch_buffer=*/nullptr, /*for_compaction=*/false,
/*async_read=*/false, tmp_status, /*use_block_cache_for_lookup=*/true));
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) {
WritableFileStringStreamAdapter out_file_wrapper(out_file);
std::ostream out_stream(&out_file_wrapper);
// Output Footer
out_stream << "Footer Details:\n"
"--------------------------------------\n";
out_stream << " " << rep_->footer.ToString() << "\n";
// Output MetaIndex
out_stream << "Metaindex Details:\n"
"--------------------------------------\n";
std::unique_ptr<Block> metaindex;
std::unique_ptr<InternalIterator> metaindex_iter;
// TODO: plumb Env::IOActivity
const ReadOptions ro;
Status s = ReadMetaIndexBlock(ro, nullptr /* prefetch_buffer */, &metaindex,
&metaindex_iter);
if (s.ok()) {
for (metaindex_iter->SeekToFirst(); metaindex_iter->Valid();
metaindex_iter->Next()) {
s = metaindex_iter->status();
if (!s.ok()) {
return s;
}
if (metaindex_iter->key() == kPropertiesBlockName) {
out_stream << " Properties block handle: "
<< metaindex_iter->value().ToString(true) << "\n";
} else if (metaindex_iter->key() == kCompressionDictBlockName) {
out_stream << " Compression dictionary block handle: "
<< metaindex_iter->value().ToString(true) << "\n";
} else if (strstr(metaindex_iter->key().ToString().c_str(),
"filter.rocksdb.") != nullptr) {
out_stream << " Filter block handle: "
<< metaindex_iter->value().ToString(true) << "\n";
} else if (metaindex_iter->key() == kRangeDelBlockName) {
out_stream << " Range deletion block handle: "
<< metaindex_iter->value().ToString(true) << "\n";
}
}
out_stream << "\n";
} else {
return s;
}
// Output TableProperties
const ROCKSDB_NAMESPACE::TableProperties* table_properties;
table_properties = rep_->table_properties.get();
if (table_properties != nullptr) {
out_stream << "Table Properties:\n"
"--------------------------------------\n";
out_stream << " " << table_properties->ToString("\n ", ": ") << "\n";
}
if (rep_->filter) {
out_stream << "Filter Details:\n"
"--------------------------------------\n";
out_stream << " " << rep_->filter->ToString() << "\n";
}
// Output Index block
s = DumpIndexBlock(out_stream);
if (!s.ok()) {
return s;
}
// Output compression dictionary
if (rep_->uncompression_dict_reader) {
CachableEntry<UncompressionDict> uncompression_dict;
s = rep_->uncompression_dict_reader->GetOrReadUncompressionDictionary(
nullptr /* prefetch_buffer */, ro, false /* no_io */,
false, /* verify_checksums */
nullptr /* get_context */, nullptr /* lookup_context */,
&uncompression_dict);
if (!s.ok()) {
return s;
}
assert(uncompression_dict.GetValue());
const Slice& raw_dict = uncompression_dict.GetValue()->GetRawDict();
out_stream << "Compression Dictionary:\n"
"--------------------------------------\n";
out_stream << " size (bytes): " << raw_dict.size() << "\n\n";
out_stream << " HEX " << raw_dict.ToString(true) << "\n\n";
}
// Output range deletions block
auto* range_del_iter = NewRangeTombstoneIterator(ro);
if (range_del_iter != nullptr) {
range_del_iter->SeekToFirst();
if (range_del_iter->Valid()) {
out_stream << "Range deletions:\n"
"--------------------------------------\n";
for (; range_del_iter->Valid(); range_del_iter->Next()) {
DumpKeyValue(range_del_iter->key(), range_del_iter->value(),
out_stream);
}
out_stream << "\n";
}
delete range_del_iter;
}
// Output Data blocks
s = DumpDataBlocks(out_stream);
if (!s.ok()) {
return s;
}
if (!out_stream.good()) {
return Status::IOError("Failed to write to output file");
}
return Status::OK();
}
Status BlockBasedTable::DumpIndexBlock(std::ostream& out_stream) {
out_stream << "Index Details:\n"
"--------------------------------------\n";
// TODO: plumb Env::IOActivity
const ReadOptions read_options;
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(read_options, /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_contex=*/nullptr));
Status s = blockhandles_iter->status();
if (!s.ok()) {
out_stream << "Can not read Index Block \n\n";
return s;
}
out_stream << " Block key hex dump: Data block handle\n";
out_stream << " 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_stream << " HEX " << user_key.ToString(true) << ": "
<< blockhandles_iter->value().ToString(true,
rep_->index_has_first_key)
<< " offset " << blockhandles_iter->value().handle.offset()
<< " size " << blockhandles_iter->value().handle.size() << "\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_stream << " ASCII " << res_key << "\n";
out_stream << " ------\n";
}
out_stream << "\n";
return Status::OK();
}
Status BlockBasedTable::DumpDataBlocks(std::ostream& out_stream) {
// TODO: plumb Env::IOActivity
const ReadOptions read_options;
std::unique_ptr<InternalIteratorBase<IndexValue>> blockhandles_iter(
NewIndexIterator(read_options, /*need_upper_bound_check=*/false,
/*input_iter=*/nullptr, /*get_context=*/nullptr,
/*lookup_contex=*/nullptr));
Status s = blockhandles_iter->status();
if (!s.ok()) {
out_stream << "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_stream << "Data Block # " << block_id << " @ "
<< blockhandles_iter->value().handle.ToString(true) << "\n";
out_stream << "--------------------------------------\n";
std::unique_ptr<InternalIterator> datablock_iter;
Status tmp_status;
datablock_iter.reset(NewDataBlockIterator<DataBlockIter>(
read_options, blockhandles_iter->value().handle,
/*input_iter=*/nullptr, /*type=*/BlockType::kData,
/*get_context=*/nullptr, /*lookup_context=*/nullptr,
/*prefetch_buffer=*/nullptr, /*for_compaction=*/false,
/*async_read=*/false, tmp_status, /*use_block_cache_for_lookup=*/true));
s = datablock_iter->status();
if (!s.ok()) {
out_stream << "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_stream << "Error reading the block - Skipped \n";
break;
}
DumpKeyValue(datablock_iter->key(), datablock_iter->value(), out_stream);
}
out_stream << "\n";
}
uint64_t num_datablocks = block_id - 1;
if (num_datablocks) {
double datablock_size_avg =
static_cast<double>(datablock_size_sum) / num_datablocks;
out_stream << "Data Block Summary:\n";
out_stream << "--------------------------------------\n";
out_stream << " # data blocks: " << num_datablocks << "\n";
out_stream << " min data block size: " << datablock_size_min << "\n";
out_stream << " max data block size: " << datablock_size_max << "\n";
out_stream << " avg data block size: "
<< std::to_string(datablock_size_avg) << "\n";
}
return Status::OK();
}
void BlockBasedTable::DumpKeyValue(const Slice& key, const Slice& value,
std::ostream& out_stream) {
InternalKey ikey;
ikey.DecodeFrom(key);
out_stream << " HEX " << ikey.user_key().ToString(true) << ": "
<< value.ToString(true) << "\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_stream << " ASCII " << res_key << ": " << res_value << "\n";
out_stream << " ------\n";
}
} // namespace ROCKSDB_NAMESPACE
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