-
Notifications
You must be signed in to change notification settings - Fork 3.8k
/
replica_data_iter.go
427 lines (393 loc) · 13 KB
/
replica_data_iter.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
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
// Copyright 2015 The Cockroach Authors.
//
// Use of this software is governed by the Business Source License
// included in the file licenses/BSL.txt.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0, included in the file
// licenses/APL.txt.
package rditer
import (
"github.com/cockroachdb/cockroach/pkg/keys"
"github.com/cockroachdb/cockroach/pkg/roachpb"
"github.com/cockroachdb/cockroach/pkg/storage"
)
// KeyRange is a helper struct for the ReplicaMVCCDataIterator and
// ReplicaEngineDataIterator.
type KeyRange struct {
Start, End roachpb.Key
}
// ReplicaMVCCDataIterator provides a complete iteration over MVCC or unversioned
// (which can be made to look like an MVCCKey) key / value
// rows in a range, including system-local metadata and user data.
// The ranges keyRange slice specifies the key ranges which comprise
// the range's data. This cannot be used to iterate over keys that are not
// representable as MVCCKeys, except when such non-MVCCKeys are limited to
// intents, which can be made to look like interleaved MVCCKeys. Most callers
// want the real keys, and should use ReplicaEngineDataIterator.
//
// A ReplicaMVCCDataIterator provides a subset of the engine.MVCCIterator interface.
//
// TODO(sumeer): merge with ReplicaEngineDataIterator. We can use an EngineIterator
// for MVCC key ranges and convert from EngineKey to MVCCKey.
type ReplicaMVCCDataIterator struct {
reader storage.Reader
curIndex int
ranges []KeyRange
// When it is non-nil, it represents the iterator for curIndex.
// A non-nil it is valid, else it is either done, or err != nil.
it storage.MVCCIterator
err error
reverse bool
}
// ReplicaEngineDataIterator is like ReplicaMVCCDataIterator, but iterates
// using the general EngineKeys. It provides a subset of the engine.EngineIterator
// interface.
type ReplicaEngineDataIterator struct {
curIndex int
ranges []KeyRange
it storage.EngineIterator
valid bool
err error
}
// MakeAllKeyRanges returns all key ranges for the given Range, in
// sorted order.
func MakeAllKeyRanges(d *roachpb.RangeDescriptor) []KeyRange {
return makeRangeKeyRanges(d, false /* replicatedOnly */)
}
// MakeReplicatedKeyRanges returns all key ranges that are fully Raft
// replicated for the given Range.
//
// NOTE: The logic for receiving snapshot relies on this function returning the
// ranges in the following sorted order:
//
// 1. Replicated range-id local key range
// 2. Range-local key range
// 3. Lock-table key ranges
// 4. User key range
func MakeReplicatedKeyRanges(d *roachpb.RangeDescriptor) []KeyRange {
return makeRangeKeyRanges(d, true /* replicatedOnly */)
}
func makeRangeKeyRanges(d *roachpb.RangeDescriptor, replicatedOnly bool) []KeyRange {
rangeIDLocal := MakeRangeIDLocalKeyRange(d.RangeID, replicatedOnly)
rangeLocal := makeRangeLocalKeyRange(d)
rangeLockTable := makeRangeLockTableKeyRanges(d)
user := MakeUserKeyRange(d)
ranges := make([]KeyRange, 5)
ranges[0] = rangeIDLocal
ranges[1] = rangeLocal
if len(rangeLockTable) != 2 {
panic("unexpected number of lock table ranges")
}
ranges[2] = rangeLockTable[0]
ranges[3] = rangeLockTable[1]
ranges[4] = user
return ranges
}
// MakeReplicatedKeyRangesExceptLockTable returns all key ranges that are fully Raft
// replicated for the given Range, except for the lock table ranges. These are
// returned in the following sorted order:
// 1. Replicated range-id local key range
// 2. Range-local key range
// 3. User key range
func MakeReplicatedKeyRangesExceptLockTable(d *roachpb.RangeDescriptor) []KeyRange {
return []KeyRange{
MakeRangeIDLocalKeyRange(d.RangeID, true /* replicatedOnly */),
makeRangeLocalKeyRange(d),
MakeUserKeyRange(d),
}
}
// MakeReplicatedKeyRangesExceptRangeID returns all key ranges that are fully Raft
// replicated for the given Range, except for the replicated range-id local key range.
// These are returned in the following sorted order:
// 1. Range-local key range
// 2. Lock-table key ranges
// 3. User key range
func MakeReplicatedKeyRangesExceptRangeID(d *roachpb.RangeDescriptor) []KeyRange {
rangeLocal := makeRangeLocalKeyRange(d)
rangeLockTable := makeRangeLockTableKeyRanges(d)
user := MakeUserKeyRange(d)
ranges := make([]KeyRange, 4)
ranges[0] = rangeLocal
if len(rangeLockTable) != 2 {
panic("unexpected number of lock table ranges")
}
ranges[1] = rangeLockTable[0]
ranges[2] = rangeLockTable[1]
ranges[3] = user
return ranges
}
// MakeRangeIDLocalKeyRange returns the range-id local key range. If
// replicatedOnly is true, then it returns only the replicated keys, otherwise,
// it only returns both the replicated and unreplicated keys.
func MakeRangeIDLocalKeyRange(rangeID roachpb.RangeID, replicatedOnly bool) KeyRange {
var prefixFn func(roachpb.RangeID) roachpb.Key
if replicatedOnly {
prefixFn = keys.MakeRangeIDReplicatedPrefix
} else {
prefixFn = keys.MakeRangeIDPrefix
}
sysRangeIDKey := prefixFn(rangeID)
return KeyRange{
Start: sysRangeIDKey,
End: sysRangeIDKey.PrefixEnd(),
}
}
// makeRangeLocalKeyRange returns the range local key range. Range-local keys
// are replicated keys that do not belong to the range they would naturally
// sort into. For example, /Local/Range/Table/1 would sort into [/Min,
// /System), but it actually belongs to [/Table/1, /Table/2).
func makeRangeLocalKeyRange(d *roachpb.RangeDescriptor) KeyRange {
return KeyRange{
Start: keys.MakeRangeKeyPrefix(d.StartKey),
End: keys.MakeRangeKeyPrefix(d.EndKey),
}
}
// makeRangeLockTableKeyRanges returns the 2 lock table key ranges.
func makeRangeLockTableKeyRanges(d *roachpb.RangeDescriptor) [2]KeyRange {
// Handle doubly-local lock table keys since range descriptor key
// is a range local key that can have a replicated lock acquired on it.
startRangeLocal, _ := keys.LockTableSingleKey(keys.MakeRangeKeyPrefix(d.StartKey), nil)
endRangeLocal, _ := keys.LockTableSingleKey(keys.MakeRangeKeyPrefix(d.EndKey), nil)
// The first range in the global keyspace can start earlier than LocalMax,
// at RKeyMin, but the actual data starts at LocalMax. We need to make this
// adjustment here to prevent [startRangeLocal, endRangeLocal) and
// [startGlobal, endGlobal) from overlapping.
globalStartKey := d.StartKey.AsRawKey()
if d.StartKey.Equal(roachpb.RKeyMin) {
globalStartKey = keys.LocalMax
}
startGlobal, _ := keys.LockTableSingleKey(globalStartKey, nil)
endGlobal, _ := keys.LockTableSingleKey(roachpb.Key(d.EndKey), nil)
return [2]KeyRange{
{
Start: startRangeLocal,
End: endRangeLocal,
},
{
Start: startGlobal,
End: endGlobal,
},
}
}
// MakeUserKeyRange returns the user key range.
func MakeUserKeyRange(d *roachpb.RangeDescriptor) KeyRange {
userKeys := d.KeySpan()
return KeyRange{
Start: userKeys.Key.AsRawKey(),
End: userKeys.EndKey.AsRawKey(),
}
}
// NewReplicaMVCCDataIterator creates a ReplicaMVCCDataIterator for the given
// replica. It iterates over the replicated key ranges excluding the lock
// table key range. Separated locks are made to appear as interleaved. The
// iterator can do one of reverse or forward iteration, based on whether
// seekEnd is true or false, respectively. With reverse iteration, it is
// initially positioned at the end of the last range, else it is initially
// positioned at the start of the first range.
//
// The iterator requires the reader.ConsistentIterators is true, since it
// creates a different iterator for each replicated key range. This is because
// MVCCIterator only allows changing the upper-bound of an existing iterator,
// and not both upper and lower bound.
func NewReplicaMVCCDataIterator(
d *roachpb.RangeDescriptor, reader storage.Reader, seekEnd bool,
) *ReplicaMVCCDataIterator {
if !reader.ConsistentIterators() {
panic("ReplicaMVCCDataIterator needs a Reader that provides ConsistentIterators")
}
ri := &ReplicaMVCCDataIterator{
reader: reader,
ranges: MakeReplicatedKeyRangesExceptLockTable(d),
reverse: seekEnd,
}
if ri.reverse {
ri.curIndex = len(ri.ranges) - 1
} else {
ri.curIndex = 0
}
ri.tryCloseAndCreateIter()
return ri
}
func (ri *ReplicaMVCCDataIterator) tryCloseAndCreateIter() {
for {
if ri.it != nil {
ri.it.Close()
ri.it = nil
}
if ri.curIndex < 0 || ri.curIndex >= len(ri.ranges) {
return
}
ri.it = ri.reader.NewMVCCIterator(
storage.MVCCKeyAndIntentsIterKind,
storage.IterOptions{
LowerBound: ri.ranges[ri.curIndex].Start,
UpperBound: ri.ranges[ri.curIndex].End,
})
if ri.reverse {
ri.it.SeekLT(storage.MakeMVCCMetadataKey(ri.ranges[ri.curIndex].End))
} else {
ri.it.SeekGE(storage.MakeMVCCMetadataKey(ri.ranges[ri.curIndex].Start))
}
if valid, err := ri.it.Valid(); valid || err != nil {
ri.err = err
return
}
if ri.reverse {
ri.curIndex--
} else {
ri.curIndex++
}
}
}
// Close the underlying iterator.
func (ri *ReplicaMVCCDataIterator) Close() {
if ri.it != nil {
ri.it.Close()
ri.it = nil
}
}
// Next advances to the next key in the iteration.
func (ri *ReplicaMVCCDataIterator) Next() {
if ri.reverse {
panic("Next called on reverse iterator")
}
ri.it.Next()
valid, err := ri.it.Valid()
if err != nil {
ri.err = err
return
}
if !valid {
ri.curIndex++
ri.tryCloseAndCreateIter()
}
}
// Prev advances the iterator one key backwards.
func (ri *ReplicaMVCCDataIterator) Prev() {
if !ri.reverse {
panic("Prev called on forward iterator")
}
ri.it.Prev()
valid, err := ri.it.Valid()
if err != nil {
ri.err = err
return
}
if !valid {
ri.curIndex--
ri.tryCloseAndCreateIter()
}
}
// Valid returns true if the iterator currently points to a valid value.
func (ri *ReplicaMVCCDataIterator) Valid() (bool, error) {
if ri.err != nil {
return false, ri.err
}
if ri.it == nil {
return false, nil
}
return true, nil
}
// Key returns the current key. Only called in tests.
func (ri *ReplicaMVCCDataIterator) Key() storage.MVCCKey {
return ri.it.Key()
}
// Value returns the current value. Only called in tests.
func (ri *ReplicaMVCCDataIterator) Value() []byte {
return ri.it.Value()
}
// UnsafeKey returns the same value as Key, but the memory is invalidated on
// the next call to {Next,Prev,Close}.
func (ri *ReplicaMVCCDataIterator) UnsafeKey() storage.MVCCKey {
return ri.it.UnsafeKey()
}
// UnsafeValue returns the same value as Value, but the memory is invalidated on
// the next call to {Next,Prev,Close}.
func (ri *ReplicaMVCCDataIterator) UnsafeValue() []byte {
return ri.it.UnsafeValue()
}
// NewReplicaEngineDataIterator creates a ReplicaEngineDataIterator for the given replica.
func NewReplicaEngineDataIterator(
d *roachpb.RangeDescriptor, reader storage.Reader, replicatedOnly bool,
) *ReplicaEngineDataIterator {
it := reader.NewEngineIterator(storage.IterOptions{UpperBound: d.EndKey.AsRawKey()})
rangeFunc := MakeAllKeyRanges
if replicatedOnly {
rangeFunc = MakeReplicatedKeyRanges
}
ri := &ReplicaEngineDataIterator{
ranges: rangeFunc(d),
it: it,
}
ri.seekStart()
return ri
}
// seekStart seeks the iterator to the start of its data range.
func (ri *ReplicaEngineDataIterator) seekStart() {
ri.curIndex = 0
ri.valid, ri.err = ri.it.SeekEngineKeyGE(storage.EngineKey{Key: ri.ranges[ri.curIndex].Start})
ri.advance()
}
// Close the underlying iterator.
func (ri *ReplicaEngineDataIterator) Close() {
ri.valid = false
ri.it.Close()
}
// Next advances to the next key in the iteration.
func (ri *ReplicaEngineDataIterator) Next() {
ri.valid, ri.err = ri.it.NextEngineKey()
ri.advance()
}
// advance moves the iterator forward through the ranges until a valid
// key is found or the iteration is done and the iterator becomes
// invalid.
func (ri *ReplicaEngineDataIterator) advance() {
for ri.valid {
var k storage.EngineKey
k, ri.err = ri.it.UnsafeEngineKey()
if ri.err != nil {
ri.valid = false
return
}
if k.Key.Compare(ri.ranges[ri.curIndex].End) < 0 {
return
}
ri.curIndex++
if ri.curIndex < len(ri.ranges) {
ri.valid, ri.err = ri.it.SeekEngineKeyGE(
storage.EngineKey{Key: ri.ranges[ri.curIndex].Start})
} else {
ri.valid = false
return
}
}
}
// Valid returns true if the iterator currently points to a valid value.
func (ri *ReplicaEngineDataIterator) Valid() (bool, error) {
return ri.valid, ri.err
}
// Value returns the current value. Only used in tests.
func (ri *ReplicaEngineDataIterator) Value() []byte {
value := ri.it.UnsafeValue()
valueCopy := make([]byte, len(value))
copy(valueCopy, value)
return valueCopy
}
// UnsafeKey returns the current key, but the memory is invalidated on the
// next call to {Next,Close}.
func (ri *ReplicaEngineDataIterator) UnsafeKey() storage.EngineKey {
key, err := ri.it.UnsafeEngineKey()
if err != nil {
// If Valid(), we've already extracted an EngineKey earlier,
// when doing the key comparison, so this will not happen.
panic("method called on an invalid iter")
}
return key
}
// UnsafeValue returns the same value as Value, but the memory is invalidated on
// the next call to {Next,Close}.
func (ri *ReplicaEngineDataIterator) UnsafeValue() []byte {
return ri.it.UnsafeValue()
}