forked from gochain/gochain
-
Notifications
You must be signed in to change notification settings - Fork 0
/
memstore.go
320 lines (274 loc) · 7.06 KB
/
memstore.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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// memory storage layer for the package blockhash
package storage
import (
"fmt"
"sync"
"github.com/gochain-io/gochain/log"
)
const (
memTreeLW = 2 // log2(subtree count) of the subtrees
memTreeFLW = 14 // log2(subtree count) of the root layer
dbForceUpdateAccessCnt = 1000
defaultCacheCapacity = 5000
)
type MemStore struct {
memtree *memTree
entryCnt, capacity uint // stored entries
accessCnt uint64 // access counter; oldest is thrown away when full
dbAccessCnt uint64
dbStore *DbStore
lock sync.Mutex
}
/*
a hash prefix subtree containing subtrees or one storage entry (but never both)
- access[0] stores the smallest (oldest) access count value in this subtree
- if it contains more subtrees and its subtree count is at least 4, access[1:2]
stores the smallest access count in the first and second halves of subtrees
(so that access[0] = min(access[1], access[2])
- likewise, if subtree count is at least 8,
access[1] = min(access[3], access[4])
access[2] = min(access[5], access[6])
(access[] is a binary tree inside the multi-bit leveled hash tree)
*/
func NewMemStore(d *DbStore, capacity uint) (m *MemStore) {
m = &MemStore{}
m.memtree = newMemTree(memTreeFLW, nil, 0)
m.dbStore = d
m.setCapacity(capacity)
return
}
type memTree struct {
subtree []*memTree
parent *memTree
parentIdx uint
bits uint // log2(subtree count)
width uint // subtree count
entry *Chunk // if subtrees are present, entry should be nil
lastDBaccess uint64
access []uint64
}
func newMemTree(b uint, parent *memTree, pidx uint) (node *memTree) {
node = new(memTree)
node.bits = b
node.width = 1 << b
node.subtree = make([]*memTree, node.width)
node.access = make([]uint64, node.width-1)
node.parent = parent
node.parentIdx = pidx
if parent != nil {
parent.subtree[pidx] = node
}
return node
}
func (node *memTree) updateAccess(a uint64) {
aidx := uint(0)
var aa uint64
oa := node.access[0]
for node.access[aidx] == oa {
node.access[aidx] = a
if aidx > 0 {
aa = node.access[((aidx-1)^1)+1]
aidx = (aidx - 1) >> 1
} else {
pidx := node.parentIdx
node = node.parent
if node == nil {
return
}
nn := node.subtree[pidx^1]
if nn != nil {
aa = nn.access[0]
} else {
aa = 0
}
aidx = (node.width + pidx - 2) >> 1
}
if (aa != 0) && (aa < a) {
a = aa
}
}
}
func (s *MemStore) setCapacity(c uint) {
s.lock.Lock()
defer s.lock.Unlock()
for c < s.entryCnt {
s.removeOldest()
}
s.capacity = c
}
// entry (not its copy) is going to be in MemStore
func (s *MemStore) Put(entry *Chunk) {
if s.capacity == 0 {
return
}
s.lock.Lock()
defer s.lock.Unlock()
if s.entryCnt >= s.capacity {
s.removeOldest()
}
s.accessCnt++
node := s.memtree
bitpos := uint(0)
for node.entry == nil {
l := entry.Key.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
st = newMemTree(memTreeLW, node, l)
bitpos += node.bits
node = st
break
}
bitpos += node.bits
node = st
}
if node.entry != nil {
if node.entry.Key.isEqual(entry.Key) {
node.updateAccess(s.accessCnt)
if entry.SData == nil {
entry.Size = node.entry.Size
entry.SData = node.entry.SData
}
if entry.Req == nil {
entry.Req = node.entry.Req
}
entry.C = node.entry.C
node.entry = entry
return
}
for node.entry != nil {
l := node.entry.Key.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
st = newMemTree(memTreeLW, node, l)
}
st.entry = node.entry
node.entry = nil
st.updateAccess(node.access[0])
l = entry.Key.bits(bitpos, node.bits)
st = node.subtree[l]
if st == nil {
st = newMemTree(memTreeLW, node, l)
}
bitpos += node.bits
node = st
}
}
node.entry = entry
node.lastDBaccess = s.dbAccessCnt
node.updateAccess(s.accessCnt)
s.entryCnt++
}
func (s *MemStore) Get(hash Key) (chunk *Chunk, err error) {
s.lock.Lock()
defer s.lock.Unlock()
node := s.memtree
bitpos := uint(0)
for node.entry == nil {
l := hash.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
return nil, notFound
}
bitpos += node.bits
node = st
}
if node.entry.Key.isEqual(hash) {
s.accessCnt++
node.updateAccess(s.accessCnt)
chunk = node.entry
if s.dbAccessCnt-node.lastDBaccess > dbForceUpdateAccessCnt {
s.dbAccessCnt++
node.lastDBaccess = s.dbAccessCnt
if s.dbStore != nil {
s.dbStore.updateAccessCnt(hash)
}
}
} else {
err = notFound
}
return
}
func (s *MemStore) removeOldest() {
node := s.memtree
for node.entry == nil {
aidx := uint(0)
av := node.access[aidx]
for aidx < node.width/2-1 {
if av == node.access[aidx*2+1] {
node.access[aidx] = node.access[aidx*2+2]
aidx = aidx*2 + 1
} else if av == node.access[aidx*2+2] {
node.access[aidx] = node.access[aidx*2+1]
aidx = aidx*2 + 2
} else {
panic(nil)
}
}
pidx := aidx*2 + 2 - node.width
if (node.subtree[pidx] != nil) && (av == node.subtree[pidx].access[0]) {
if node.subtree[pidx+1] != nil {
node.access[aidx] = node.subtree[pidx+1].access[0]
} else {
node.access[aidx] = 0
}
} else if (node.subtree[pidx+1] != nil) && (av == node.subtree[pidx+1].access[0]) {
if node.subtree[pidx] != nil {
node.access[aidx] = node.subtree[pidx].access[0]
} else {
node.access[aidx] = 0
}
pidx++
} else {
panic(nil)
}
//fmt.Println(pidx)
node = node.subtree[pidx]
}
if node.entry.dbStored != nil {
log.Trace(fmt.Sprintf("Memstore Clean: Waiting for chunk %v to be saved", node.entry.Key.Log()))
<-node.entry.dbStored
log.Trace(fmt.Sprintf("Memstore Clean: Chunk %v saved to DBStore. Ready to clear from mem.", node.entry.Key.Log()))
} else {
log.Trace(fmt.Sprintf("Memstore Clean: Chunk %v already in DB. Ready to delete.", node.entry.Key.Log()))
}
if node.entry.SData != nil {
node.entry = nil
s.entryCnt--
}
node.access[0] = 0
//---
aidx := uint(0)
for {
aa := node.access[aidx]
if aidx > 0 {
aidx = (aidx - 1) >> 1
} else {
pidx := node.parentIdx
node = node.parent
if node == nil {
return
}
aidx = (node.width + pidx - 2) >> 1
}
if (aa != 0) && ((aa < node.access[aidx]) || (node.access[aidx] == 0)) {
node.access[aidx] = aa
}
}
}
// Close memstore
func (s *MemStore) Close() {}