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rocksdb/cache/compressed_secondary_cache.h

86 lines
2.8 KiB

// 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).
#pragma once
#include <memory>
#include "cache/lru_cache.h"
#include "memory/memory_allocator.h"
#include "rocksdb/secondary_cache.h"
#include "rocksdb/slice.h"
#include "rocksdb/status.h"
#include "util/compression.h"
namespace ROCKSDB_NAMESPACE {
class CompressedSecondaryCacheResultHandle : public SecondaryCacheResultHandle {
public:
CompressedSecondaryCacheResultHandle(void* value, size_t size)
: value_(value), size_(size) {}
virtual ~CompressedSecondaryCacheResultHandle() override = default;
CompressedSecondaryCacheResultHandle(
const CompressedSecondaryCacheResultHandle&) = delete;
CompressedSecondaryCacheResultHandle& operator=(
const CompressedSecondaryCacheResultHandle&) = delete;
bool IsReady() override { return true; }
void Wait() override {}
void* Value() override { return value_; }
size_t Size() override { return size_; }
private:
void* value_;
size_t size_;
};
// The CompressedSecondaryCache is a concrete implementation of
// rocksdb::SecondaryCache.
//
// Users can also cast a pointer to it and call methods on
// it directly, especially custom methods that may be added
// in the future. For example -
// std::unique_ptr<rocksdb::SecondaryCache> cache =
// NewCompressedSecondaryCache(opts);
// static_cast<CompressedSecondaryCache*>(cache.get())->Erase(key);
class CompressedSecondaryCache : public SecondaryCache {
public:
CompressedSecondaryCache(
size_t capacity, int num_shard_bits, bool strict_capacity_limit,
double high_pri_pool_ratio, double low_pri_pool_ratio,
std::shared_ptr<MemoryAllocator> memory_allocator = nullptr,
bool use_adaptive_mutex = kDefaultToAdaptiveMutex,
CacheMetadataChargePolicy metadata_charge_policy =
kDontChargeCacheMetadata,
CompressionType compression_type = CompressionType::kLZ4Compression,
uint32_t compress_format_version = 2);
virtual ~CompressedSecondaryCache() override;
const char* Name() const override { return "CompressedSecondaryCache"; }
Status Insert(const Slice& key, void* value,
const Cache::CacheItemHelper* helper) override;
std::unique_ptr<SecondaryCacheResultHandle> Lookup(
const Slice& key, const Cache::CreateCallback& create_cb, bool /*wait*/,
bool& is_in_sec_cache) override;
void Erase(const Slice& key) override;
void WaitAll(std::vector<SecondaryCacheResultHandle*> /*handles*/) override {}
std::string GetPrintableOptions() const override;
private:
std::shared_ptr<Cache> cache_;
CompressedSecondaryCacheOptions cache_options_;
};
} // namespace ROCKSDB_NAMESPACE