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serathiusserathius
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Use immutable binary tree for index
Signed-off-by: Marek Siarkowicz <[email protected]>
1 parent e26043f commit 4d92c28

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4 files changed

+588
-644
lines changed

4 files changed

+588
-644
lines changed

‎server/storage/mvcc/index.go

+117-138
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,8 @@
1515
package mvcc
1616

1717
import (
18-
"sync"
18+
"bytes"
19+
"fmt"
1920

2021
"github.com/google/btree"
2122
"go.uber.org/zap"
@@ -30,103 +31,105 @@ type index interface {
3031
Tombstone(key []byte, rev Revision) error
3132
Compact(rev int64) map[Revision]struct{}
3233
Keep(rev int64) map[Revision]struct{}
33-
Equal(b index) bool
34-
35-
Insert(ki *keyIndex)
36-
KeyIndex(ki *keyIndex) *keyIndex
3734
}
3835

3936
type treeIndex struct {
40-
sync.RWMutex
41-
tree *btree.BTreeG[*keyIndex]
42-
lg *zap.Logger
37+
baseRev int64
38+
revisionTree []*btree.BTreeG[keyRev]
39+
lg *zap.Logger
4340
}
4441

45-
func newTreeIndex(lg *zap.Logger) index {
46-
return &treeIndex{
47-
tree: btree.NewG(32, func(aki *keyIndex, bki *keyIndex) bool {
48-
return aki.Less(bki)
49-
}),
50-
lg: lg,
51-
}
42+
type keyRev struct {
43+
key []byte
44+
mod, created Revision
45+
version int64
5246
}
5347

54-
func (ti *treeIndex) Put(key []byte, rev Revision) {
55-
keyi := &keyIndex{key: key}
56-
57-
ti.Lock()
58-
defer ti.Unlock()
59-
okeyi, ok := ti.tree.Get(keyi)
60-
if !ok {
61-
keyi.put(ti.lg, rev.Main, rev.Sub)
62-
ti.tree.ReplaceOrInsert(keyi)
63-
return
64-
}
65-
okeyi.put(ti.lg, rev.Main, rev.Sub)
48+
var lessThen btree.LessFunc[keyRev] = func(k keyRev, k2 keyRev) bool {
49+
return compare(k, k2) == -1
6650
}
6751

68-
func (ti *treeIndex) Get(key []byte, atRev int64) (modified, created Revision, ver int64, err error) {
69-
ti.RLock()
70-
defer ti.RUnlock()
71-
return ti.unsafeGet(key, atRev)
52+
func compare(k keyRev, k2 keyRev) int {
53+
return bytes.Compare(k.key, k2.key)
7254
}
7355

74-
func (ti *treeIndex) unsafeGet(key []byte, atRev int64) (modified, created Revision, ver int64, err error) {
75-
keyi := &keyIndex{key: key}
76-
if keyi = ti.keyIndex(keyi); keyi == nil {
77-
return Revision{}, Revision{}, 0, ErrRevisionNotFound
56+
func newTreeIndex(lg *zap.Logger) index {
57+
return &treeIndex{
58+
baseRev: 1,
59+
lg: lg,
60+
revisionTree: []*btree.BTreeG[keyRev]{
61+
btree.NewG(32, lessThen),
62+
},
7863
}
79-
return keyi.get(ti.lg, atRev)
8064
}
8165

82-
func (ti *treeIndex) KeyIndex(keyi *keyIndex) *keyIndex {
83-
ti.RLock()
84-
defer ti.RUnlock()
85-
return ti.keyIndex(keyi)
86-
}
87-
88-
func (ti *treeIndex) keyIndex(keyi *keyIndex) *keyIndex {
89-
if ki, ok := ti.tree.Get(keyi); ok {
90-
return ki
66+
func (ti *treeIndex) Put(key []byte, rev Revision) {
67+
prevTree := ti.revisionTree[len(ti.revisionTree)-1]
68+
item, found := prevTree.Get(keyRev{key: key})
69+
created := rev
70+
var version int64 = 1
71+
if found {
72+
created = item.created
73+
version = item.version + 1
74+
}
75+
tirev := ti.rev()
76+
if rev.Main == tirev {
77+
prevTree.ReplaceOrInsert(keyRev{
78+
key: key,
79+
mod: rev,
80+
created: created,
81+
version: version,
82+
})
83+
} else if rev.Main == tirev+1 {
84+
newTree := prevTree.Clone()
85+
newTree.ReplaceOrInsert(keyRev{
86+
key: key,
87+
mod: rev,
88+
created: created,
89+
version: version,
90+
})
91+
ti.revisionTree = append(ti.revisionTree, newTree)
92+
} else {
93+
panic(fmt.Sprintf("append only, lastRev: %d, putRev: %d", ti.rev(), rev.Main))
9194
}
92-
return nil
9395
}
9496

95-
func (ti *treeIndex) unsafeVisit(key, end []byte, f func(ki *keyIndex) bool) {
96-
keyi, endi := &keyIndex{key: key}, &keyIndex{key: end}
97+
func (ti *treeIndex) rev() int64 {
98+
return ti.baseRev + int64(len(ti.revisionTree)) - 1
99+
}
97100

98-
ti.tree.AscendGreaterOrEqual(keyi, func(item *keyIndex) bool {
99-
if len(endi.key) > 0 && !item.Less(endi) {
100-
return false
101-
}
102-
if !f(item) {
103-
return false
104-
}
105-
return true
106-
})
101+
func (ti *treeIndex) Get(key []byte, atRev int64) (modified, created Revision, ver int64, err error) {
102+
tree, err := ti.forRev(atRev)
103+
if err != nil {
104+
return modified, created, ver, err
105+
}
106+
keyRev, found := tree.Get(keyRev{key: key})
107+
if !found {
108+
return Revision{}, Revision{}, 0, ErrRevisionNotFound
109+
}
110+
return keyRev.mod, keyRev.created, keyRev.version, nil
107111
}
108112

109113
// Revisions returns limited number of revisions from key(included) to end(excluded)
110114
// at the given rev. The returned slice is sorted in the order of key. There is no limit if limit <= 0.
111115
// The second return parameter isn't capped by the limit and reflects the total number of revisions.
112116
func (ti *treeIndex) Revisions(key, end []byte, atRev int64, limit int) (revs []Revision, total int) {
113-
ti.RLock()
114-
defer ti.RUnlock()
115-
116117
if end == nil {
117-
rev, _, _, err := ti.unsafeGet(key, atRev)
118+
rev, _, _, err := ti.Get(key, atRev)
118119
if err != nil {
119120
return nil, 0
120121
}
121122
return []Revision{rev}, 1
122123
}
123-
ti.unsafeVisit(key, end, func(ki *keyIndex) bool {
124-
if rev, _, _, err := ki.get(ti.lg, atRev); err == nil {
125-
if limit <= 0 || len(revs) < limit {
126-
revs = append(revs, rev)
127-
}
128-
total++
124+
tree, err := ti.forRev(atRev)
125+
if err != nil {
126+
return revs, total
127+
}
128+
tree.AscendRange(keyRev{key: key}, keyRev{key: end}, func(kr keyRev) bool {
129+
if limit <= 0 || len(revs) < limit {
130+
revs = append(revs, kr.mod)
129131
}
132+
total++
130133
return true
131134
})
132135
return revs, total
@@ -135,119 +138,95 @@ func (ti *treeIndex) Revisions(key, end []byte, atRev int64, limit int) (revs []
135138
// CountRevisions returns the number of revisions
136139
// from key(included) to end(excluded) at the given rev.
137140
func (ti *treeIndex) CountRevisions(key, end []byte, atRev int64) int {
138-
ti.RLock()
139-
defer ti.RUnlock()
140-
141141
if end == nil {
142-
_, _, _, err := ti.unsafeGet(key, atRev)
142+
_, _, _, err := ti.Get(key, atRev)
143143
if err != nil {
144144
return 0
145145
}
146146
return 1
147147
}
148148
total := 0
149-
ti.unsafeVisit(key, end, func(ki *keyIndex) bool {
150-
if _, _, _, err := ki.get(ti.lg, atRev); err == nil {
151-
total++
152-
}
149+
tree, err := ti.forRev(atRev)
150+
if err != nil {
151+
return total
152+
}
153+
tree.AscendRange(keyRev{key: key}, keyRev{key: end}, func(kr keyRev) bool {
154+
total++
153155
return true
154156
})
155157
return total
156158
}
157159

158160
func (ti *treeIndex) Range(key, end []byte, atRev int64) (keys [][]byte, revs []Revision) {
159-
ti.RLock()
160-
defer ti.RUnlock()
161-
162161
if end == nil {
163-
rev, _, _, err := ti.unsafeGet(key, atRev)
162+
rev, _, _, err := ti.Get(key, atRev)
164163
if err != nil {
165164
return nil, nil
166165
}
167166
return [][]byte{key}, []Revision{rev}
168167
}
169-
ti.unsafeVisit(key, end, func(ki *keyIndex) bool {
170-
if rev, _, _, err := ki.get(ti.lg, atRev); err == nil {
171-
revs = append(revs, rev)
172-
keys = append(keys, ki.key)
173-
}
168+
tree, err := ti.forRev(atRev)
169+
if err != nil {
170+
return keys, revs
171+
}
172+
tree.AscendRange(keyRev{key: key}, keyRev{key: end}, func(kr keyRev) bool {
173+
revs = append(revs, kr.mod)
174+
keys = append(keys, kr.key)
174175
return true
175176
})
176177
return keys, revs
177178
}
178179

179180
func (ti *treeIndex) Tombstone(key []byte, rev Revision) error {
180-
keyi := &keyIndex{key: key}
181-
182-
ti.Lock()
183-
defer ti.Unlock()
184-
ki, ok := ti.tree.Get(keyi)
185-
if !ok {
181+
prevTree := ti.revisionTree[len(ti.revisionTree)-1]
182+
tirev := ti.rev()
183+
var found bool
184+
if rev.Main == tirev {
185+
_, found = prevTree.Delete(keyRev{
186+
key: key,
187+
})
188+
} else if rev.Main == tirev+1 {
189+
newTree := prevTree.Clone()
190+
_, found = newTree.Delete(keyRev{
191+
key: key,
192+
})
193+
ti.revisionTree = append(ti.revisionTree, newTree)
194+
} else {
195+
panic(fmt.Sprintf("append only, lastRev: %d, putRev: %d", ti.rev(), rev.Main))
196+
}
197+
if !found {
186198
return ErrRevisionNotFound
187199
}
188-
189-
return ki.tombstone(ti.lg, rev.Main, rev.Sub)
200+
return nil
190201
}
191202

192203
func (ti *treeIndex) Compact(rev int64) map[Revision]struct{} {
193204
available := make(map[Revision]struct{})
194205
ti.lg.Info("compact tree index", zap.Int64("revision", rev))
195-
ti.Lock()
196-
clone := ti.tree.Clone()
197-
ti.Unlock()
198-
199-
clone.Ascend(func(keyi *keyIndex) bool {
200-
// Lock is needed here to prevent modification to the keyIndex while
201-
// compaction is going on or revision added to empty before deletion
202-
ti.Lock()
203-
keyi.compact(ti.lg, rev, available)
204-
if keyi.isEmpty() {
205-
_, ok := ti.tree.Delete(keyi)
206-
if !ok {
207-
ti.lg.Panic("failed to delete during compaction")
208-
}
209-
}
210-
ti.Unlock()
211-
return true
212-
})
206+
idx := rev - ti.baseRev
207+
ti.revisionTree = ti.revisionTree[idx:]
208+
ti.baseRev = rev
213209
return available
214210
}
215211

216212
// Keep finds all revisions to be kept for a Compaction at the given rev.
217213
func (ti *treeIndex) Keep(rev int64) map[Revision]struct{} {
218214
available := make(map[Revision]struct{})
219-
ti.RLock()
220-
defer ti.RUnlock()
221-
ti.tree.Ascend(func(keyi *keyIndex) bool {
222-
keyi.keep(rev, available)
215+
tree, err := ti.forRev(rev)
216+
if err != nil {
217+
return available
218+
}
219+
tree.Ascend(func(item keyRev) bool {
220+
available[item.mod] = struct{}{}
223221
return true
224222
})
225223
return available
226224
}
227225

228-
func (ti *treeIndex) Equal(bi index) bool {
229-
b := bi.(*treeIndex)
230-
231-
if ti.tree.Len() != b.tree.Len() {
232-
return false
226+
func (ti *treeIndex) forRev(rev int64) (*btree.BTreeG[keyRev], error) {
227+
idx := rev - ti.baseRev
228+
if idx < 0 || idx >= int64(len(ti.revisionTree)) {
229+
return nil, ErrRevisionNotFound
233230
}
234-
235-
equal := true
236-
237-
ti.tree.Ascend(func(aki *keyIndex) bool {
238-
bki, _ := b.tree.Get(aki)
239-
if !aki.equal(bki) {
240-
equal = false
241-
return false
242-
}
243-
return true
244-
})
245-
246-
return equal
247-
}
248-
249-
func (ti *treeIndex) Insert(ki *keyIndex) {
250-
ti.Lock()
251-
defer ti.Unlock()
252-
ti.tree.ReplaceOrInsert(ki)
231+
return ti.revisionTree[idx], nil
253232
}

‎server/storage/mvcc/index_bench_test.go

+9-9
Original file line numberDiff line numberDiff line change
@@ -24,21 +24,21 @@ import (
2424
"go.uber.org/zap"
2525
)
2626

27-
func BenchmarkIndexCompactBase(b *testing.B) { benchmarkIndexCompact(b, 3, 100) }
28-
func BenchmarkIndexCompactLongKey(b *testing.B) { benchmarkIndexCompact(b, 512, 100) }
29-
func BenchmarkIndexCompactLargeKeySpace(b *testing.B) { benchmarkIndexCompact(b, 3, 100000) }
27+
//func BenchmarkIndexCompactBase(b *testing.B) { benchmarkIndexCompact(b, 3, 100) }
28+
//func BenchmarkIndexCompactLongKey(b *testing.B) { benchmarkIndexCompact(b, 512, 100) }
29+
//func BenchmarkIndexCompactLargeKeySpace(b *testing.B) { benchmarkIndexCompact(b, 3, 100000) }
3030

31-
func BenchmarkIndexKeepBase(b *testing.B) { benchmarkIndexKeep(b, 3, 100) }
32-
func BenchmarkIndexKeepLongKey(b *testing.B) { benchmarkIndexKeep(b, 512, 100) }
33-
func BenchmarkIndexKeepLargeKeySpace(b *testing.B) { benchmarkIndexKeep(b, 3, 100000) }
31+
//func BenchmarkIndexKeepBase(b *testing.B) { benchmarkIndexKeep(b, 3, 100) }
32+
//func BenchmarkIndexKeepLongKey(b *testing.B) { benchmarkIndexKeep(b, 512, 100) }
33+
//func BenchmarkIndexKeepLargeKeySpace(b *testing.B) { benchmarkIndexKeep(b, 3, 100000) }
3434

3535
func BenchmarkIndexPutBase(b *testing.B) { benchmarkIndexPut(b, 3, 100) }
3636
func BenchmarkIndexPutLongKey(b *testing.B) { benchmarkIndexPut(b, 512, 100) }
3737
func BenchmarkIndexPutLargeKeySpace(b *testing.B) { benchmarkIndexPut(b, 3, 100000) }
3838

39-
func BenchmarkIndexTombstoneBase(b *testing.B) { benchmarkIndexTombstone(b, 3, 100, 25) }
40-
func BenchmarkIndexTombstoneLongKey(b *testing.B) { benchmarkIndexTombstone(b, 512, 100, 25) }
41-
func BenchmarkIndexTombstoneLargeKeySpace(b *testing.B) { benchmarkIndexTombstone(b, 3, 100000, 25) }
39+
//func BenchmarkIndexTombstoneBase(b *testing.B) { benchmarkIndexTombstone(b, 3, 100, 25) }
40+
//func BenchmarkIndexTombstoneLongKey(b *testing.B) { benchmarkIndexTombstone(b, 512, 100, 25) }
41+
//func BenchmarkIndexTombstoneLargeKeySpace(b *testing.B) { benchmarkIndexTombstone(b, 3, 100000, 25) }
4242

4343
func BenchmarkIndexGetBase(b *testing.B) { benchmarkIndexGet(b, 3, 100, 1, 25) }
4444
func BenchmarkIndexGetRepeatedKeys(b *testing.B) { benchmarkIndexGet(b, 3, 100, 1000, 25) }

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