rocksdb/db/version_builder.h
Changyu Bi 62fc15f009 Block per key-value checksum (#11287)
Summary:
add option `block_protection_bytes_per_key` and implementation for block per key-value checksum. The main changes are
1. checksum construction and verification in block.cc/h
2. pass the option `block_protection_bytes_per_key` around (mainly for methods defined in table_cache.h)
3. unit tests/crash test updates

Tests:
* Added unit tests
* Crash test: `python3 tools/db_crashtest.py blackbox --simple --block_protection_bytes_per_key=1 --write_buffer_size=1048576`

Follow up (maybe as a separate PR): make sure corruption status returned from BlockIters are correctly handled.

Performance:
Turning on block per KV protection has a non-trivial negative impact on read performance and costs additional memory.
For memory, each block includes additional 24 bytes for checksum-related states beside checksum itself. For CPU, I set up a DB of size ~1.2GB with 5M keys (32 bytes key and 200 bytes value) which compacts to ~5 SST files (target file size 256 MB) in L6 without compression. I tested readrandom performance with various block cache size (to mimic various cache hit rates):

```
SETUP
make OPTIMIZE_LEVEL="-O3" USE_LTO=1 DEBUG_LEVEL=0 -j32 db_bench
./db_bench -benchmarks=fillseq,compact0,waitforcompaction,compact,waitforcompaction -write_buffer_size=33554432 -level_compaction_dynamic_level_bytes=true -max_background_jobs=8 -target_file_size_base=268435456 --num=5000000 --key_size=32 --value_size=200 --compression_type=none

BENCHMARK
./db_bench --use_existing_db -benchmarks=readtocache,readrandom[-X10] --num=5000000 --key_size=32 --disable_auto_compactions --reads=1000000 --block_protection_bytes_per_key=[0|1] --cache_size=$CACHESIZE

The readrandom ops/sec looks like the following:
Block cache size:  2GB        1.2GB * 0.9    1.2GB * 0.8     1.2GB * 0.5   8MB
Main              240805     223604         198176           161653       139040
PR prot_bytes=0   238691     226693         200127           161082       141153
PR prot_bytes=1   214983     193199         178532           137013       108211
prot_bytes=1 vs    -10%        -15%          -10.8%          -15%        -23%
prot_bytes=0
```

The benchmark has a lot of variance, but there was a 5% to 25% regression in this benchmark with different cache hit rates.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11287

Reviewed By: ajkr

Differential Revision: D43970708

Pulled By: cbi42

fbshipit-source-id: ef98d898b71779846fa74212b9ec9e08b7183940
2023-04-25 12:08:23 -07:00

94 lines
3.1 KiB
C++

// 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.
//
#pragma once
#include <memory>
#include "db/version_edit.h"
#include "rocksdb/file_system.h"
#include "rocksdb/metadata.h"
#include "rocksdb/slice_transform.h"
namespace ROCKSDB_NAMESPACE {
struct ImmutableCFOptions;
class TableCache;
class VersionStorageInfo;
class VersionEdit;
struct FileMetaData;
class InternalStats;
class Version;
class VersionSet;
class ColumnFamilyData;
class CacheReservationManager;
// A helper class so we can efficiently apply a whole sequence
// of edits to a particular state without creating intermediate
// Versions that contain full copies of the intermediate state.
class VersionBuilder {
public:
VersionBuilder(const FileOptions& file_options,
const ImmutableCFOptions* ioptions, TableCache* table_cache,
VersionStorageInfo* base_vstorage, VersionSet* version_set,
std::shared_ptr<CacheReservationManager>
file_metadata_cache_res_mgr = nullptr);
~VersionBuilder();
bool CheckConsistencyForNumLevels();
Status Apply(const VersionEdit* edit);
Status SaveTo(VersionStorageInfo* vstorage) const;
Status LoadTableHandlers(
InternalStats* internal_stats, int max_threads,
bool prefetch_index_and_filter_in_cache, bool is_initial_load,
const std::shared_ptr<const SliceTransform>& prefix_extractor,
size_t max_file_size_for_l0_meta_pin, const ReadOptions& read_options,
uint8_t block_protection_bytes_per_key);
uint64_t GetMinOldestBlobFileNumber() const;
private:
class Rep;
std::unique_ptr<Rep> rep_;
};
// A wrapper of version builder which references the current version in
// constructor and unref it in the destructor.
// Both of the constructor and destructor need to be called inside DB Mutex.
class BaseReferencedVersionBuilder {
public:
explicit BaseReferencedVersionBuilder(ColumnFamilyData* cfd);
BaseReferencedVersionBuilder(ColumnFamilyData* cfd, Version* v);
~BaseReferencedVersionBuilder();
VersionBuilder* version_builder() const { return version_builder_.get(); }
private:
std::unique_ptr<VersionBuilder> version_builder_;
Version* version_;
};
class NewestFirstBySeqNo {
public:
bool operator()(const FileMetaData* lhs, const FileMetaData* rhs) const {
assert(lhs);
assert(rhs);
if (lhs->fd.largest_seqno != rhs->fd.largest_seqno) {
return lhs->fd.largest_seqno > rhs->fd.largest_seqno;
}
if (lhs->fd.smallest_seqno != rhs->fd.smallest_seqno) {
return lhs->fd.smallest_seqno > rhs->fd.smallest_seqno;
}
// Break ties by file number
return lhs->fd.GetNumber() > rhs->fd.GetNumber();
}
};
} // namespace ROCKSDB_NAMESPACE