rocksdb/utilities/cache_dump_load_impl.h
Peter Dillinger efd035164b Meta-internal folly integration with F14FastMap (#9546)
Summary:
Especially after updating to C++17, I don't see a compelling case for
*requiring* any folly components in RocksDB. I was able to purge the existing
hard dependencies, and it can be quite difficult to strip out non-trivial components
from folly for use in RocksDB. (The prospect of doing that on F14 has changed
my mind on the best approach here.)

But this change creates an optional integration where we can plug in
components from folly at compile time, starting here with F14FastMap to replace
std::unordered_map when possible (probably no public APIs for example). I have
replaced the biggest CPU users of std::unordered_map with compile-time
pluggable UnorderedMap which will use F14FastMap when USE_FOLLY is set.
USE_FOLLY is always set in the Meta-internal buck build, and a simulation of
that is in the Makefile for public CI testing. A full folly build is not needed, but
checking out the full folly repo is much simpler for getting the dependency,
and anything else we might want to optionally integrate in the future.

Some picky details:
* I don't think the distributed mutex stuff is actually used, so it was easy to remove.
* I implemented an alternative to `folly::constexpr_log2` (which is much easier
in C++17 than C++11) so that I could pull out the hard dependencies on
`ConstexprMath.h`
* I had to add noexcept move constructors/operators to some types to make
F14's complainUnlessNothrowMoveAndDestroy check happy, and I added a
macro to make that easier in some common cases.
* Updated Meta-internal buck build to use folly F14Map (always)

No updates to HISTORY.md nor INSTALL.md as this is not (yet?) considered a
production integration for open source users.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9546

Test Plan:
CircleCI tests updated so that a couple of them use folly.

Most internal unit & stress/crash tests updated to use Meta-internal latest folly.
(Note: they should probably use buck but they currently use Makefile.)

Example performance improvement: when filter partitions are pinned in cache,
they are tracked by PartitionedFilterBlockReader::filter_map_ and we can build
a test that exercises that heavily. Build DB with

```
TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom -num=10000000 -disable_wal=1 -write_buffer_size=30000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -partition_index_and_filters
```

and test with (simultaneous runs with & without folly, ~20 times each to see
convergence)

```
TEST_TMPDIR=/dev/shm/rocksdb ./db_bench_folly -readonly -use_existing_db -benchmarks=readrandom -num=10000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -partition_index_and_filters -duration=40 -pin_l0_filter_and_index_blocks_in_cache
```

Average ops/s no folly: 26229.2
Average ops/s with folly: 26853.3 (+2.4%)

Reviewed By: ajkr

Differential Revision: D34181736

Pulled By: pdillinger

fbshipit-source-id: ffa6ad5104c2880321d8a1aa7187e00ab0d02e94
2022-04-13 07:34:01 -07:00

367 lines
12 KiB
C++

// Copyright (c) Facebook, Inc. and its affiliates. 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).
#pragma once
#ifndef ROCKSDB_LITE
#include <unordered_map>
#include "file/random_access_file_reader.h"
#include "file/writable_file_writer.h"
#include "rocksdb/utilities/cache_dump_load.h"
#include "table/block_based/block.h"
#include "table/block_based/block_like_traits.h"
#include "table/block_based/block_type.h"
#include "table/block_based/cachable_entry.h"
#include "table/block_based/parsed_full_filter_block.h"
#include "table/block_based/reader_common.h"
namespace ROCKSDB_NAMESPACE {
// the read buffer size of for the default CacheDumpReader
const unsigned int kDumpReaderBufferSize = 1024; // 1KB
static const unsigned int kSizePrefixLen = 4;
enum CacheDumpUnitType : unsigned char {
kHeader = 1,
kFooter = 2,
kData = 3,
kFilter = 4,
kProperties = 5,
kCompressionDictionary = 6,
kRangeDeletion = 7,
kHashIndexPrefixes = 8,
kHashIndexMetadata = 9,
kMetaIndex = 10,
kIndex = 11,
kDeprecatedFilterBlock = 12,
kFilterMetaBlock = 13,
kBlockTypeMax,
};
// The metadata of a dump unit. After it is serilized, its size is fixed 16
// bytes.
struct DumpUnitMeta {
// sequence number is a monotonically increasing number to indicate the order
// of the blocks being written. Header is 0.
uint32_t sequence_num;
// The Crc32c checksum of its dump unit.
uint32_t dump_unit_checksum;
// The dump unit size after the dump unit is serilized to a string.
uint64_t dump_unit_size;
void reset() {
sequence_num = 0;
dump_unit_checksum = 0;
dump_unit_size = 0;
}
};
// The data structure to hold a block and its information.
struct DumpUnit {
// The timestamp when the block is identified, copied, and dumped from block
// cache
uint64_t timestamp;
// The type of the block
CacheDumpUnitType type;
// The key of this block when the block is referenced by this Cache
Slice key;
// The block size
size_t value_len;
// The Crc32c checksum of the block
uint32_t value_checksum;
// Pointer to the block. Note that, in the dump process, it points to a memory
// buffer copied from cache block. The buffer is freed when we process the
// next block. In the load process, we use an std::string to store the
// serilized dump_unit read from the reader. So it points to the memory
// address of the begin of the block in this string.
void* value;
DumpUnit() { reset(); }
void reset() {
timestamp = 0;
type = CacheDumpUnitType::kBlockTypeMax;
key.clear();
value_len = 0;
value_checksum = 0;
value = nullptr;
}
};
// The default implementation of the Cache Dumper
class CacheDumperImpl : public CacheDumper {
public:
CacheDumperImpl(const CacheDumpOptions& dump_options,
const std::shared_ptr<Cache>& cache,
std::unique_ptr<CacheDumpWriter>&& writer)
: options_(dump_options), cache_(cache), writer_(std::move(writer)) {}
~CacheDumperImpl() { writer_.reset(); }
Status SetDumpFilter(std::vector<DB*> db_list) override;
IOStatus DumpCacheEntriesToWriter() override;
private:
IOStatus WriteRawBlock(uint64_t timestamp, CacheDumpUnitType type,
const Slice& key, void* value, size_t len,
uint32_t checksum);
IOStatus WriteHeader();
IOStatus WriteCacheBlock(const CacheDumpUnitType type, const Slice& key,
void* value, size_t len);
IOStatus WriteFooter();
bool ShouldFilterOut(const Slice& key);
std::function<void(const Slice&, void*, size_t, Cache::DeleterFn)>
DumpOneBlockCallBack();
CacheDumpOptions options_;
std::shared_ptr<Cache> cache_;
std::unique_ptr<CacheDumpWriter> writer_;
UnorderedMap<Cache::DeleterFn, CacheEntryRole> role_map_;
SystemClock* clock_;
uint32_t sequence_num_;
// The cache key prefix filter. Currently, we use db_session_id as the prefix,
// so using std::set to store the prefixes as filter is enough. Further
// improvement can be applied like BloomFilter or others to speedup the
// filtering.
std::set<std::string> prefix_filter_;
};
// The default implementation of CacheDumpedLoader
class CacheDumpedLoaderImpl : public CacheDumpedLoader {
public:
CacheDumpedLoaderImpl(const CacheDumpOptions& dump_options,
const BlockBasedTableOptions& toptions,
const std::shared_ptr<SecondaryCache>& secondary_cache,
std::unique_ptr<CacheDumpReader>&& reader)
: options_(dump_options),
toptions_(toptions),
secondary_cache_(secondary_cache),
reader_(std::move(reader)) {}
~CacheDumpedLoaderImpl() {}
IOStatus RestoreCacheEntriesToSecondaryCache() override;
private:
IOStatus ReadDumpUnitMeta(std::string* data, DumpUnitMeta* unit_meta);
IOStatus ReadDumpUnit(size_t len, std::string* data, DumpUnit* unit);
IOStatus ReadHeader(std::string* data, DumpUnit* dump_unit);
IOStatus ReadCacheBlock(std::string* data, DumpUnit* dump_unit);
CacheDumpOptions options_;
const BlockBasedTableOptions& toptions_;
std::shared_ptr<SecondaryCache> secondary_cache_;
std::unique_ptr<CacheDumpReader> reader_;
UnorderedMap<Cache::DeleterFn, CacheEntryRole> role_map_;
};
// The default implementation of CacheDumpWriter. We write the blocks to a file
// sequentially.
class ToFileCacheDumpWriter : public CacheDumpWriter {
public:
explicit ToFileCacheDumpWriter(
std::unique_ptr<WritableFileWriter>&& file_writer)
: file_writer_(std::move(file_writer)) {}
~ToFileCacheDumpWriter() { Close().PermitUncheckedError(); }
// Write the serilized metadata to the file
virtual IOStatus WriteMetadata(const Slice& metadata) override {
assert(file_writer_ != nullptr);
std::string prefix;
PutFixed32(&prefix, static_cast<uint32_t>(metadata.size()));
IOStatus io_s = file_writer_->Append(Slice(prefix));
if (!io_s.ok()) {
return io_s;
}
io_s = file_writer_->Append(metadata);
return io_s;
}
// Write the serilized data to the file
virtual IOStatus WritePacket(const Slice& data) override {
assert(file_writer_ != nullptr);
std::string prefix;
PutFixed32(&prefix, static_cast<uint32_t>(data.size()));
IOStatus io_s = file_writer_->Append(Slice(prefix));
if (!io_s.ok()) {
return io_s;
}
io_s = file_writer_->Append(data);
return io_s;
}
// Reset the writer
virtual IOStatus Close() override {
file_writer_.reset();
return IOStatus::OK();
}
private:
std::unique_ptr<WritableFileWriter> file_writer_;
};
// The default implementation of CacheDumpReader. It is implemented based on
// RandomAccessFileReader. Note that, we keep an internal variable to remember
// the current offset.
class FromFileCacheDumpReader : public CacheDumpReader {
public:
explicit FromFileCacheDumpReader(
std::unique_ptr<RandomAccessFileReader>&& reader)
: file_reader_(std::move(reader)),
offset_(0),
buffer_(new char[kDumpReaderBufferSize]) {}
~FromFileCacheDumpReader() { delete[] buffer_; }
virtual IOStatus ReadMetadata(std::string* metadata) override {
uint32_t metadata_len = 0;
IOStatus io_s = ReadSizePrefix(&metadata_len);
if (!io_s.ok()) {
return io_s;
}
return Read(metadata_len, metadata);
}
virtual IOStatus ReadPacket(std::string* data) override {
uint32_t data_len = 0;
IOStatus io_s = ReadSizePrefix(&data_len);
if (!io_s.ok()) {
return io_s;
}
return Read(data_len, data);
}
private:
IOStatus ReadSizePrefix(uint32_t* len) {
std::string prefix;
IOStatus io_s = Read(kSizePrefixLen, &prefix);
if (!io_s.ok()) {
return io_s;
}
Slice encoded_slice(prefix);
if (!GetFixed32(&encoded_slice, len)) {
return IOStatus::Corruption("Decode size prefix string failed");
}
return IOStatus::OK();
}
IOStatus Read(size_t len, std::string* data) {
assert(file_reader_ != nullptr);
IOStatus io_s;
unsigned int bytes_to_read = static_cast<unsigned int>(len);
unsigned int to_read = bytes_to_read > kDumpReaderBufferSize
? kDumpReaderBufferSize
: bytes_to_read;
while (to_read > 0) {
io_s = file_reader_->Read(IOOptions(), offset_, to_read, &result_,
buffer_, nullptr,
Env::IO_TOTAL /* rate_limiter_priority */);
if (!io_s.ok()) {
return io_s;
}
if (result_.size() < to_read) {
return IOStatus::Corruption("Corrupted cache dump file.");
}
data->append(result_.data(), result_.size());
offset_ += to_read;
bytes_to_read -= to_read;
to_read = bytes_to_read > kDumpReaderBufferSize ? kDumpReaderBufferSize
: bytes_to_read;
}
return io_s;
}
std::unique_ptr<RandomAccessFileReader> file_reader_;
Slice result_;
size_t offset_;
char* buffer_;
};
// The cache dump and load helper class
class CacheDumperHelper {
public:
// serilize the dump_unit_meta to a string, it is fixed 16 bytes size.
static void EncodeDumpUnitMeta(const DumpUnitMeta& meta, std::string* data) {
assert(data);
PutFixed32(data, static_cast<uint32_t>(meta.sequence_num));
PutFixed32(data, static_cast<uint32_t>(meta.dump_unit_checksum));
PutFixed64(data, meta.dump_unit_size);
}
// Serilize the dump_unit to a string.
static void EncodeDumpUnit(const DumpUnit& dump_unit, std::string* data) {
assert(data);
PutFixed64(data, dump_unit.timestamp);
data->push_back(dump_unit.type);
PutLengthPrefixedSlice(data, dump_unit.key);
PutFixed32(data, static_cast<uint32_t>(dump_unit.value_len));
PutFixed32(data, dump_unit.value_checksum);
PutLengthPrefixedSlice(data,
Slice((char*)dump_unit.value, dump_unit.value_len));
}
// Deserilize the dump_unit_meta from a string
static Status DecodeDumpUnitMeta(const std::string& encoded_data,
DumpUnitMeta* unit_meta) {
assert(unit_meta != nullptr);
Slice encoded_slice = Slice(encoded_data);
if (!GetFixed32(&encoded_slice, &(unit_meta->sequence_num))) {
return Status::Incomplete("Decode dumped unit meta sequence_num failed");
}
if (!GetFixed32(&encoded_slice, &(unit_meta->dump_unit_checksum))) {
return Status::Incomplete(
"Decode dumped unit meta dump_unit_checksum failed");
}
if (!GetFixed64(&encoded_slice, &(unit_meta->dump_unit_size))) {
return Status::Incomplete(
"Decode dumped unit meta dump_unit_size failed");
}
return Status::OK();
}
// Deserilize the dump_unit from a string.
static Status DecodeDumpUnit(const std::string& encoded_data,
DumpUnit* dump_unit) {
assert(dump_unit != nullptr);
Slice encoded_slice = Slice(encoded_data);
// Decode timestamp
if (!GetFixed64(&encoded_slice, &dump_unit->timestamp)) {
return Status::Incomplete("Decode dumped unit string failed");
}
// Decode the block type
dump_unit->type = static_cast<CacheDumpUnitType>(encoded_slice[0]);
encoded_slice.remove_prefix(1);
// Decode the key
if (!GetLengthPrefixedSlice(&encoded_slice, &(dump_unit->key))) {
return Status::Incomplete("Decode dumped unit string failed");
}
// Decode the value size
uint32_t value_len;
if (!GetFixed32(&encoded_slice, &value_len)) {
return Status::Incomplete("Decode dumped unit string failed");
}
dump_unit->value_len = static_cast<size_t>(value_len);
// Decode the value checksum
if (!GetFixed32(&encoded_slice, &(dump_unit->value_checksum))) {
return Status::Incomplete("Decode dumped unit string failed");
}
// Decode the block content and copy to the memory space whose pointer
// will be managed by the cache finally.
Slice block;
if (!GetLengthPrefixedSlice(&encoded_slice, &block)) {
return Status::Incomplete("Decode dumped unit string failed");
}
dump_unit->value = (void*)block.data();
assert(block.size() == dump_unit->value_len);
return Status::OK();
}
};
} // namespace ROCKSDB_NAMESPACE
#endif // ROCKSDB_LITE