1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
// 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).
#pragma once
#include <cinttypes>
#include <memory>
#include "cache/cache_helpers.h"
#include "cache/cache_key.h"
#include "db/blob/blob_file_cache.h"
#include "db/blob/blob_read_request.h"
#include "rocksdb/cache.h"
#include "rocksdb/rocksdb_namespace.h"
#include "table/block_based/cachable_entry.h"
#include "util/autovector.h"
namespace ROCKSDB_NAMESPACE {
struct ImmutableOptions;
class Status;
class FilePrefetchBuffer;
class Slice;
class BlobContents;
// BlobSource is a class that provides universal access to blobs, regardless of
// whether they are in the blob cache, secondary cache, or (remote) storage.
// Depending on user settings, it always fetch blobs from multi-tier cache and
// storage with minimal cost.
class BlobSource {
public:
BlobSource(const ImmutableOptions* immutable_options,
const std::string& db_id, const std::string& db_session_id,
BlobFileCache* blob_file_cache);
BlobSource(const BlobSource&) = delete;
BlobSource& operator=(const BlobSource&) = delete;
~BlobSource();
// Read a blob from the underlying cache or one blob file.
//
// If successful, returns ok and sets "*value" to the newly retrieved
// uncompressed blob. If there was an error while fetching the blob, sets
// "*value" to empty and returns a non-ok status.
//
// Note: For consistency, whether the blob is found in the cache or on disk,
// sets "*bytes_read" to the size of on-disk (possibly compressed) blob
// record.
Status GetBlob(const ReadOptions& read_options, const Slice& user_key,
uint64_t file_number, uint64_t offset, uint64_t file_size,
uint64_t value_size, CompressionType compression_type,
FilePrefetchBuffer* prefetch_buffer, PinnableSlice* value,
uint64_t* bytes_read);
// Read multiple blobs from the underlying cache or blob file(s).
//
// If successful, returns ok and sets "result" in the elements of "blob_reqs"
// to the newly retrieved uncompressed blobs. If there was an error while
// fetching one of blobs, sets its "result" to empty and sets its
// corresponding "status" to a non-ok status.
//
// Note:
// - The main difference between this function and MultiGetBlobFromOneFile is
// that this function can read multiple blobs from multiple blob files.
//
// - For consistency, whether the blob is found in the cache or on disk, sets
// "*bytes_read" to the total size of on-disk (possibly compressed) blob
// records.
void MultiGetBlob(const ReadOptions& read_options,
autovector<BlobFileReadRequests>& blob_reqs,
uint64_t* bytes_read);
// Read multiple blobs from the underlying cache or one blob file.
//
// If successful, returns ok and sets "result" in the elements of "blob_reqs"
// to the newly retrieved uncompressed blobs. If there was an error while
// fetching one of blobs, sets its "result" to empty and sets its
// corresponding "status" to a non-ok status.
//
// Note:
// - The main difference between this function and MultiGetBlob is that this
// function is only used for the case where the demanded blobs are stored in
// one blob file. MultiGetBlob will call this function multiple times if the
// demanded blobs are stored in multiple blob files.
//
// - For consistency, whether the blob is found in the cache or on disk, sets
// "*bytes_read" to the total size of on-disk (possibly compressed) blob
// records.
void MultiGetBlobFromOneFile(const ReadOptions& read_options,
uint64_t file_number, uint64_t file_size,
autovector<BlobReadRequest>& blob_reqs,
uint64_t* bytes_read);
inline Status GetBlobFileReader(
uint64_t blob_file_number,
CacheHandleGuard<BlobFileReader>* blob_file_reader) {
return blob_file_cache_->GetBlobFileReader(blob_file_number,
blob_file_reader);
}
inline Cache* GetBlobCache() const { return blob_cache_.get(); }
bool TEST_BlobInCache(uint64_t file_number, uint64_t file_size,
uint64_t offset, size_t* charge = nullptr) const;
private:
Status GetBlobFromCache(const Slice& cache_key,
CacheHandleGuard<BlobContents>* cached_blob) const;
Status PutBlobIntoCache(const Slice& cache_key,
std::unique_ptr<BlobContents>* blob,
CacheHandleGuard<BlobContents>* cached_blob) const;
static void PinCachedBlob(CacheHandleGuard<BlobContents>* cached_blob,
PinnableSlice* value);
static void PinOwnedBlob(std::unique_ptr<BlobContents>* owned_blob,
PinnableSlice* value);
Cache::Handle* GetEntryFromCache(const Slice& key) const;
Status InsertEntryIntoCache(const Slice& key, BlobContents* value,
size_t charge, Cache::Handle** cache_handle,
Cache::Priority priority) const;
inline CacheKey GetCacheKey(uint64_t file_number, uint64_t /*file_size*/,
uint64_t offset) const {
OffsetableCacheKey base_cache_key(db_id_, db_session_id_, file_number);
return base_cache_key.WithOffset(offset);
}
const std::string& db_id_;
const std::string& db_session_id_;
Statistics* statistics_;
// A cache to store blob file reader.
BlobFileCache* blob_file_cache_;
// A cache to store uncompressed blobs.
std::shared_ptr<Cache> blob_cache_;
// The control option of how the cache tiers will be used. Currently rocksdb
// support block/blob cache (volatile tier) and secondary cache (this tier
// isn't strictly speaking a non-volatile tier since the compressed cache in
// this tier is in volatile memory).
const CacheTier lowest_used_cache_tier_;
};
} // namespace ROCKSDB_NAMESPACE
|
