forked from pingcap/tidb
-
Notifications
You must be signed in to change notification settings - Fork 0
/
coprocessor_cache.go
184 lines (162 loc) · 4.66 KB
/
coprocessor_cache.go
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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
// Copyright 2019 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package tikv
import (
"bytes"
"encoding/binary"
"fmt"
"math"
"time"
"unsafe"
"github.com/dgraph-io/ristretto"
"github.com/pingcap/errors"
"github.com/pingcap/kvproto/pkg/coprocessor"
"github.com/pingcap/tidb/config"
)
type coprCache struct {
cache *ristretto.Cache
admissionMaxSize int
admissionMinProcessTime time.Duration
}
type coprCacheValue struct {
Key []byte
Data []byte
TimeStamp uint64
RegionID uint64
RegionDataVersion uint64
}
func (v *coprCacheValue) String() string {
return fmt.Sprintf("{ Ts = %d, RegionID = %d, RegionDataVersion = %d, len(Data) = %d }",
v.TimeStamp,
v.RegionID,
v.RegionDataVersion,
len(v.Data))
}
const coprCacheValueSize = int(unsafe.Sizeof(coprCacheValue{}))
func (v *coprCacheValue) Len() int {
return coprCacheValueSize + len(v.Key) + len(v.Data)
}
func newCoprCache(config *config.CoprocessorCache) (*coprCache, error) {
if config == nil || !config.Enabled {
return nil, nil
}
capacityInBytes := int64(config.CapacityMB * 1024.0 * 1024.0)
if capacityInBytes == 0 {
return nil, errors.New("Capacity must be > 0 to enable the cache")
}
maxEntityInBytes := int64(config.AdmissionMaxResultMB * 1024.0 * 1024.0)
if maxEntityInBytes == 0 {
return nil, errors.New("AdmissionMaxResultMB must be > 0 to enable the cache")
}
estimatedEntities := capacityInBytes / maxEntityInBytes * 2
if estimatedEntities < 10 {
estimatedEntities = 10
}
cache, err := ristretto.NewCache(&ristretto.Config{
NumCounters: estimatedEntities * 10,
MaxCost: capacityInBytes,
BufferItems: 64,
})
if err != nil {
return nil, errors.Trace(err)
}
c := coprCache{
cache: cache,
admissionMaxSize: int(maxEntityInBytes),
admissionMinProcessTime: time.Duration(config.AdmissionMinProcessMs) * time.Millisecond,
}
return &c, nil
}
func coprCacheBuildKey(copReq *coprocessor.Request) ([]byte, error) {
// Calculate amount of space to allocate
if copReq.Tp > math.MaxUint8 {
return nil, errors.New("Request Tp too big")
}
if len(copReq.Data) > math.MaxUint32 {
return nil, errors.New("Cache data too big")
}
totalLength := 1 + 4 + len(copReq.Data)
for _, r := range copReq.Ranges {
if len(r.Start) > math.MaxUint16 {
return nil, errors.New("Cache start key too big")
}
if len(r.End) > math.MaxUint16 {
return nil, errors.New("Cache end key too big")
}
totalLength += 2 + len(r.Start) + 2 + len(r.End)
}
key := make([]byte, totalLength)
// 1 byte Tp
key[0] = uint8(copReq.Tp)
dest := 1
// 4 bytes Data len
binary.LittleEndian.PutUint32(key[dest:], uint32(len(copReq.Data)))
dest += 4
// N bytes Data
copy(key[dest:], copReq.Data)
dest += len(copReq.Data)
for _, r := range copReq.Ranges {
// 2 bytes Key len
binary.LittleEndian.PutUint16(key[dest:], uint16(len(r.Start)))
dest += 2
// N bytes Key
copy(key[dest:], r.Start)
dest += len(r.Start)
// 2 bytes Key len
binary.LittleEndian.PutUint16(key[dest:], uint16(len(r.End)))
dest += 2
// N bytes Key
copy(key[dest:], r.End)
dest += len(r.End)
}
return key, nil
}
// Get gets a cache item according to cache key.
func (c *coprCache) Get(key []byte) *coprCacheValue {
if c == nil {
return nil
}
value, hit := c.cache.Get(key)
if !hit {
return nil
}
typedValue := value.(*coprCacheValue)
// ristretto does not handle hash collision, so check the key equality after getting a value.
if !bytes.Equal(typedValue.Key, key) {
return nil
}
return typedValue
}
// CheckAdmission checks whether an item is worth caching.
func (c *coprCache) CheckAdmission(dataSize int, processTime time.Duration) bool {
if c == nil {
return false
}
if dataSize == 0 || dataSize > c.admissionMaxSize {
return false
}
if processTime < c.admissionMinProcessTime {
return false
}
return true
}
// Set inserts an item to the cache.
// It is recommended to call `CheckAdmission` before inserting the item to the cache.
func (c *coprCache) Set(key []byte, value *coprCacheValue) bool {
if c == nil {
return false
}
// Always ensure that the `Key` in `value` is the `key` we received.
value.Key = key
return c.cache.Set(key, value, int64(value.Len()))
}