rocksdb/table/block_based/block_cache.cc
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

107 lines
4.7 KiB
C++

// Copyright (c) Meta Platforms, Inc. and affiliates.
// 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).
#include "table/block_based/block_cache.h"
namespace ROCKSDB_NAMESPACE {
void BlockCreateContext::Create(std::unique_ptr<Block_kData>* parsed_out,
BlockContents&& block) {
parsed_out->reset(new Block_kData(
std::move(block), table_options->read_amp_bytes_per_bit, statistics));
parsed_out->get()->InitializeDataBlockProtectionInfo(protection_bytes_per_key,
raw_ucmp);
}
void BlockCreateContext::Create(std::unique_ptr<Block_kIndex>* parsed_out,
BlockContents&& block) {
parsed_out->reset(new Block_kIndex(std::move(block),
/*read_amp_bytes_per_bit*/ 0, statistics));
parsed_out->get()->InitializeIndexBlockProtectionInfo(
protection_bytes_per_key, raw_ucmp, index_value_is_full,
index_has_first_key);
}
void BlockCreateContext::Create(
std::unique_ptr<Block_kFilterPartitionIndex>* parsed_out,
BlockContents&& block) {
parsed_out->reset(new Block_kFilterPartitionIndex(
std::move(block), /*read_amp_bytes_per_bit*/ 0, statistics));
parsed_out->get()->InitializeIndexBlockProtectionInfo(
protection_bytes_per_key, raw_ucmp, index_value_is_full,
index_has_first_key);
}
void BlockCreateContext::Create(
std::unique_ptr<Block_kRangeDeletion>* parsed_out, BlockContents&& block) {
parsed_out->reset(new Block_kRangeDeletion(
std::move(block), /*read_amp_bytes_per_bit*/ 0, statistics));
}
void BlockCreateContext::Create(std::unique_ptr<Block_kMetaIndex>* parsed_out,
BlockContents&& block) {
parsed_out->reset(new Block_kMetaIndex(
std::move(block), /*read_amp_bytes_per_bit*/ 0, statistics));
parsed_out->get()->InitializeMetaIndexBlockProtectionInfo(
protection_bytes_per_key);
}
void BlockCreateContext::Create(
std::unique_ptr<ParsedFullFilterBlock>* parsed_out, BlockContents&& block) {
parsed_out->reset(new ParsedFullFilterBlock(
table_options->filter_policy.get(), std::move(block)));
}
void BlockCreateContext::Create(std::unique_ptr<UncompressionDict>* parsed_out,
BlockContents&& block) {
parsed_out->reset(new UncompressionDict(
block.data, std::move(block.allocation), using_zstd));
}
namespace {
// For getting SecondaryCache-compatible helpers from a BlockType. This is
// useful for accessing block cache in untyped contexts, such as for generic
// cache warming in table builder.
const std::array<const Cache::CacheItemHelper*,
static_cast<unsigned>(BlockType::kInvalid) + 1>
kCacheItemFullHelperForBlockType{{
BlockCacheInterface<Block_kData>::GetFullHelper(),
BlockCacheInterface<ParsedFullFilterBlock>::GetFullHelper(),
BlockCacheInterface<Block_kFilterPartitionIndex>::GetFullHelper(),
nullptr, // kProperties
BlockCacheInterface<UncompressionDict>::GetFullHelper(),
BlockCacheInterface<Block_kRangeDeletion>::GetFullHelper(),
nullptr, // kHashIndexPrefixes
nullptr, // kHashIndexMetadata
nullptr, // kMetaIndex (not yet stored in block cache)
BlockCacheInterface<Block_kIndex>::GetFullHelper(),
nullptr, // kInvalid
}};
// For getting basic helpers from a BlockType (no SecondaryCache support)
const std::array<const Cache::CacheItemHelper*,
static_cast<unsigned>(BlockType::kInvalid) + 1>
kCacheItemBasicHelperForBlockType{{
BlockCacheInterface<Block_kData>::GetBasicHelper(),
BlockCacheInterface<ParsedFullFilterBlock>::GetBasicHelper(),
BlockCacheInterface<Block_kFilterPartitionIndex>::GetBasicHelper(),
nullptr, // kProperties
BlockCacheInterface<UncompressionDict>::GetBasicHelper(),
BlockCacheInterface<Block_kRangeDeletion>::GetBasicHelper(),
nullptr, // kHashIndexPrefixes
nullptr, // kHashIndexMetadata
nullptr, // kMetaIndex (not yet stored in block cache)
BlockCacheInterface<Block_kIndex>::GetBasicHelper(),
nullptr, // kInvalid
}};
} // namespace
const Cache::CacheItemHelper* GetCacheItemHelper(
BlockType block_type, CacheTier lowest_used_cache_tier) {
if (lowest_used_cache_tier == CacheTier::kNonVolatileBlockTier) {
return kCacheItemFullHelperForBlockType[static_cast<unsigned>(block_type)];
} else {
return kCacheItemBasicHelperForBlockType[static_cast<unsigned>(block_type)];
}
}
} // namespace ROCKSDB_NAMESPACE