rocksdb/cache/cache.cc
Gang Liao 275cd80cdb Add a blob-specific cache priority (#10461)
Summary:
RocksDB's `Cache` abstraction currently supports two priority levels for items: high (used for frequently accessed/highly valuable SST metablocks like index/filter blocks) and low (used for SST data blocks). Blobs are typically lower-value targets for caching than data blocks, since 1) with BlobDB, data blocks containing blob references conceptually form an index structure which has to be consulted before we can read the blob value, and 2) cached blobs represent only a single key-value, while cached data blocks generally contain multiple KVs. Since we would like to make it possible to use the same backing cache for the block cache and the blob cache, it would make sense to add a new, lower-than-low cache priority level (bottom level) for blobs so data blocks are prioritized over them.

This task is a part of https://github.com/facebook/rocksdb/issues/10156

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10461

Reviewed By: siying

Differential Revision: D38672823

Pulled By: ltamasi

fbshipit-source-id: 90cf7362036563d79891f47be2cc24b827482743
2022-08-12 17:59:06 -07:00

125 lines
4.7 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.
#include "rocksdb/cache.h"
#include "cache/lru_cache.h"
#include "rocksdb/secondary_cache.h"
#include "rocksdb/utilities/customizable_util.h"
#include "rocksdb/utilities/options_type.h"
#include "util/string_util.h"
namespace ROCKSDB_NAMESPACE {
#ifndef ROCKSDB_LITE
static std::unordered_map<std::string, OptionTypeInfo>
lru_cache_options_type_info = {
{"capacity",
{offsetof(struct LRUCacheOptions, capacity), OptionType::kSizeT,
OptionVerificationType::kNormal, OptionTypeFlags::kMutable}},
{"num_shard_bits",
{offsetof(struct LRUCacheOptions, num_shard_bits), OptionType::kInt,
OptionVerificationType::kNormal, OptionTypeFlags::kMutable}},
{"strict_capacity_limit",
{offsetof(struct LRUCacheOptions, strict_capacity_limit),
OptionType::kBoolean, OptionVerificationType::kNormal,
OptionTypeFlags::kMutable}},
{"high_pri_pool_ratio",
{offsetof(struct LRUCacheOptions, high_pri_pool_ratio),
OptionType::kDouble, OptionVerificationType::kNormal,
OptionTypeFlags::kMutable}},
{"low_pri_pool_ratio",
{offsetof(struct LRUCacheOptions, low_pri_pool_ratio),
OptionType::kDouble, OptionVerificationType::kNormal,
OptionTypeFlags::kMutable}},
};
static std::unordered_map<std::string, OptionTypeInfo>
comp_sec_cache_options_type_info = {
{"capacity",
{offsetof(struct CompressedSecondaryCacheOptions, capacity),
OptionType::kSizeT, OptionVerificationType::kNormal,
OptionTypeFlags::kMutable}},
{"num_shard_bits",
{offsetof(struct CompressedSecondaryCacheOptions, num_shard_bits),
OptionType::kInt, OptionVerificationType::kNormal,
OptionTypeFlags::kMutable}},
{"compression_type",
{offsetof(struct CompressedSecondaryCacheOptions, compression_type),
OptionType::kCompressionType, OptionVerificationType::kNormal,
OptionTypeFlags::kMutable}},
{"compress_format_version",
{offsetof(struct CompressedSecondaryCacheOptions,
compress_format_version),
OptionType::kUInt32T, OptionVerificationType::kNormal,
OptionTypeFlags::kMutable}},
};
#endif // ROCKSDB_LITE
Status SecondaryCache::CreateFromString(
const ConfigOptions& config_options, const std::string& value,
std::shared_ptr<SecondaryCache>* result) {
if (value.find("compressed_secondary_cache://") == 0) {
std::string args = value;
args.erase(0, std::strlen("compressed_secondary_cache://"));
Status status;
std::shared_ptr<SecondaryCache> sec_cache;
#ifndef ROCKSDB_LITE
CompressedSecondaryCacheOptions sec_cache_opts;
status = OptionTypeInfo::ParseStruct(config_options, "",
&comp_sec_cache_options_type_info, "",
args, &sec_cache_opts);
if (status.ok()) {
sec_cache = NewCompressedSecondaryCache(sec_cache_opts);
}
#else
(void)config_options;
status = Status::NotSupported(
"Cannot load compressed secondary cache in LITE mode ", args);
#endif //! ROCKSDB_LITE
if (status.ok()) {
result->swap(sec_cache);
}
return status;
} else {
return LoadSharedObject<SecondaryCache>(config_options, value, nullptr,
result);
}
}
Status Cache::CreateFromString(const ConfigOptions& config_options,
const std::string& value,
std::shared_ptr<Cache>* result) {
Status status;
std::shared_ptr<Cache> cache;
if (value.find('=') == std::string::npos) {
cache = NewLRUCache(ParseSizeT(value));
} else {
#ifndef ROCKSDB_LITE
LRUCacheOptions cache_opts;
status = OptionTypeInfo::ParseStruct(config_options, "",
&lru_cache_options_type_info, "",
value, &cache_opts);
if (status.ok()) {
cache = NewLRUCache(cache_opts);
}
#else
(void)config_options;
status = Status::NotSupported("Cannot load cache in LITE mode ", value);
#endif //! ROCKSDB_LITE
}
if (status.ok()) {
result->swap(cache);
}
return status;
}
} // namespace ROCKSDB_NAMESPACE