forked from influxdata/influxdb
-
Notifications
You must be signed in to change notification settings - Fork 0
/
cache.go
700 lines (593 loc) · 19.4 KB
/
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
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
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
package tsm1
import (
"fmt"
"math"
"os"
"sync"
"sync/atomic"
"time"
"github.com/influxdata/influxdb/models"
"github.com/influxdata/influxdb/tsdb"
"go.uber.org/zap"
)
// ringShards specifies the number of partitions that the hash ring used to
// store the entry mappings contains. It must be a power of 2. From empirical
// testing, a value above the number of cores on the machine does not provide
// any additional benefit. For now we'll set it to the number of cores on the
// largest box we could imagine running influx.
const ringShards = 128
var (
// ErrSnapshotInProgress is returned if a snapshot is attempted while one is already running.
ErrSnapshotInProgress = fmt.Errorf("snapshot in progress")
)
// ErrCacheMemorySizeLimitExceeded returns an error indicating an operation
// could not be completed due to exceeding the cache-max-memory-size setting.
func ErrCacheMemorySizeLimitExceeded(n, limit uint64) error {
return fmt.Errorf("cache-max-memory-size exceeded: (%d/%d)", n, limit)
}
// entry is a set of values and some metadata.
type entry struct {
mu sync.RWMutex
values Values // All stored values.
// The type of values stored. Read only so doesn't need to be protected by
// mu.
vtype int
}
// newEntryValues returns a new instance of entry with the given values. If the
// values are not valid, an error is returned.
//
// newEntryValues takes an optional hint to indicate the initial buffer size.
// The hint is only respected if it's positive.
func newEntryValues(values []Value, hint int) (*entry, error) {
// Ensure we start off with a reasonably sized values slice.
if hint < 32 {
hint = 32
}
e := &entry{}
if len(values) >= hint {
e.values = values
} else {
e.values = make(Values, 0, hint)
e.values = append(e.values, values...)
}
// No values, don't check types and ordering
if len(values) == 0 {
return e, nil
}
et := valueType(values[0])
for _, v := range values {
// Make sure all the values are the same type
if et != valueType(v) {
return nil, tsdb.ErrFieldTypeConflict
}
}
// Set the type of values stored.
e.vtype = et
return e, nil
}
// add adds the given values to the entry.
func (e *entry) add(values []Value) error {
if len(values) == 0 {
return nil // Nothing to do.
}
// Are any of the new values the wrong type?
for _, v := range values {
if e.vtype != valueType(v) {
return tsdb.ErrFieldTypeConflict
}
}
// entry currently has no values, so add the new ones and we're done.
e.mu.Lock()
if len(e.values) == 0 {
// Ensure we start off with a reasonably sized values slice.
if len(values) < 32 {
e.values = make(Values, 0, 32)
e.values = append(e.values, values...)
} else {
e.values = values
}
e.mu.Unlock()
return nil
}
// Append the new values to the existing ones...
e.values = append(e.values, values...)
e.mu.Unlock()
return nil
}
// deduplicate sorts and orders the entry's values. If values are already deduped and sorted,
// the function does no work and simply returns.
func (e *entry) deduplicate() {
e.mu.Lock()
defer e.mu.Unlock()
if len(e.values) == 0 {
return
}
e.values = e.values.Deduplicate()
}
// count returns the number of values in this entry.
func (e *entry) count() int {
e.mu.RLock()
n := len(e.values)
e.mu.RUnlock()
return n
}
// filter removes all values with timestamps between min and max inclusive.
func (e *entry) filter(min, max int64) {
e.mu.Lock()
e.values = e.values.Exclude(min, max)
e.mu.Unlock()
}
// size returns the size of this entry in bytes.
func (e *entry) size() int {
e.mu.RLock()
sz := e.values.Size()
e.mu.RUnlock()
return sz
}
// Statistics gathered by the Cache.
const (
// levels - point in time measures
statCacheMemoryBytes = "memBytes" // level: Size of in-memory cache in bytes
statCacheDiskBytes = "diskBytes" // level: Size of on-disk snapshots in bytes
statSnapshots = "snapshotCount" // level: Number of active snapshots.
statCacheAgeMs = "cacheAgeMs" // level: Number of milliseconds since cache was last snapshoted at sample time
// counters - accumulative measures
statCachedBytes = "cachedBytes" // counter: Total number of bytes written into snapshots.
statWALCompactionTimeMs = "WALCompactionTimeMs" // counter: Total number of milliseconds spent compacting snapshots
statCacheWriteOK = "writeOk"
statCacheWriteErr = "writeErr"
statCacheWriteDropped = "writeDropped"
)
// storer is the interface that descibes a cache's store.
type storer interface {
entry(key string) (*entry, bool) // Get an entry by its key.
write(key string, values Values) error // Write an entry to the store.
add(key string, entry *entry) // Add a new entry to the store.
remove(key string) // Remove an entry from the store.
keys(sorted bool) []string // Return an optionally sorted slice of entry keys.
apply(f func(string, *entry) error) error // Apply f to all entries in the store in parallel.
applySerial(f func(string, *entry) error) error // Apply f to all entries in serial.
reset() // Reset the store to an initial unused state.
}
// Cache maintains an in-memory store of Values for a set of keys.
type Cache struct {
// Due to a bug in atomic size needs to be the first word in the struct, as
// that's the only place where you're guaranteed to be 64-bit aligned on a
// 32 bit system. See: https://golang.org/pkg/sync/atomic/#pkg-note-BUG
size uint64
snapshotSize uint64
mu sync.RWMutex
store storer
maxSize uint64
// snapshots are the cache objects that are currently being written to tsm files
// they're kept in memory while flushing so they can be queried along with the cache.
// they are read only and should never be modified
snapshot *Cache
snapshotting bool
// This number is the number of pending or failed WriteSnaphot attempts since the last successful one.
snapshotAttempts int
stats *CacheStatistics
lastSnapshot time.Time
}
// NewCache returns an instance of a cache which will use a maximum of maxSize bytes of memory.
// Only used for engine caches, never for snapshots.
func NewCache(maxSize uint64, path string) *Cache {
store, _ := newring(ringShards)
c := &Cache{
maxSize: maxSize,
store: store, // Max size for now..
stats: &CacheStatistics{},
lastSnapshot: time.Now(),
}
c.UpdateAge()
c.UpdateCompactTime(0)
c.updateCachedBytes(0)
c.updateMemSize(0)
c.updateSnapshots()
return c
}
// CacheStatistics hold statistics related to the cache.
type CacheStatistics struct {
MemSizeBytes int64
DiskSizeBytes int64
SnapshotCount int64
CacheAgeMs int64
CachedBytes int64
WALCompactionTimeMs int64
WriteOK int64
WriteErr int64
WriteDropped int64
}
// Statistics returns statistics for periodic monitoring.
func (c *Cache) Statistics(tags map[string]string) []models.Statistic {
return []models.Statistic{{
Name: "tsm1_cache",
Tags: tags,
Values: map[string]interface{}{
statCacheMemoryBytes: atomic.LoadInt64(&c.stats.MemSizeBytes),
statCacheDiskBytes: atomic.LoadInt64(&c.stats.DiskSizeBytes),
statSnapshots: atomic.LoadInt64(&c.stats.SnapshotCount),
statCacheAgeMs: atomic.LoadInt64(&c.stats.CacheAgeMs),
statCachedBytes: atomic.LoadInt64(&c.stats.CachedBytes),
statWALCompactionTimeMs: atomic.LoadInt64(&c.stats.WALCompactionTimeMs),
statCacheWriteOK: atomic.LoadInt64(&c.stats.WriteOK),
statCacheWriteErr: atomic.LoadInt64(&c.stats.WriteErr),
statCacheWriteDropped: atomic.LoadInt64(&c.stats.WriteDropped),
},
}}
}
// Write writes the set of values for the key to the cache. This function is goroutine-safe.
// It returns an error if the cache will exceed its max size by adding the new values.
func (c *Cache) Write(key string, values []Value) error {
addedSize := uint64(Values(values).Size())
// Enough room in the cache?
limit := c.maxSize
n := c.Size() + atomic.LoadUint64(&c.snapshotSize) + addedSize
if limit > 0 && n > limit {
atomic.AddInt64(&c.stats.WriteErr, 1)
return ErrCacheMemorySizeLimitExceeded(n, limit)
}
if err := c.store.write(key, values); err != nil {
atomic.AddInt64(&c.stats.WriteErr, 1)
return err
}
// Update the cache size and the memory size stat.
c.increaseSize(addedSize)
c.updateMemSize(int64(addedSize))
atomic.AddInt64(&c.stats.WriteOK, 1)
return nil
}
// WriteMulti writes the map of keys and associated values to the cache. This
// function is goroutine-safe. It returns an error if the cache will exceeded
// its max size by adding the new values. The write attempts to write as many
// values as possible. If one key fails, the others can still succeed and an
// error will be returned.
func (c *Cache) WriteMulti(values map[string][]Value) error {
var addedSize uint64
for _, v := range values {
addedSize += uint64(Values(v).Size())
}
// Enough room in the cache?
limit := c.maxSize // maxSize is safe for reading without a lock.
n := c.Size() + atomic.LoadUint64(&c.snapshotSize) + addedSize
if limit > 0 && n > limit {
atomic.AddInt64(&c.stats.WriteErr, 1)
return ErrCacheMemorySizeLimitExceeded(n, limit)
}
var werr error
c.mu.RLock()
store := c.store
c.mu.RUnlock()
// We'll optimistially set size here, and then decrement it for write errors.
c.increaseSize(addedSize)
for k, v := range values {
if err := store.write(k, v); err != nil {
// The write failed, hold onto the error and adjust the size delta.
werr = err
addedSize -= uint64(Values(v).Size())
c.decreaseSize(uint64(Values(v).Size()))
}
}
// Some points in the batch were dropped. An error is returned so
// error stat is incremented as well.
if werr != nil {
atomic.AddInt64(&c.stats.WriteDropped, 1)
atomic.AddInt64(&c.stats.WriteErr, 1)
}
// Update the memory size stat
c.updateMemSize(int64(addedSize))
atomic.AddInt64(&c.stats.WriteOK, 1)
return werr
}
// Snapshot takes a snapshot of the current cache, adds it to the slice of caches that
// are being flushed, and resets the current cache with new values.
func (c *Cache) Snapshot() (*Cache, error) {
c.mu.Lock()
defer c.mu.Unlock()
if c.snapshotting {
return nil, ErrSnapshotInProgress
}
c.snapshotting = true
c.snapshotAttempts++ // increment the number of times we tried to do this
// If no snapshot exists, create a new one, otherwise update the existing snapshot
if c.snapshot == nil {
store, err := newring(ringShards)
if err != nil {
return nil, err
}
c.snapshot = &Cache{
store: store,
}
}
// Did a prior snapshot exist that failed? If so, return the existing
// snapshot to retry.
if c.snapshot.Size() > 0 {
return c.snapshot, nil
}
c.snapshot.store, c.store = c.store, c.snapshot.store
snapshotSize := c.Size()
// Save the size of the snapshot on the snapshot cache
atomic.StoreUint64(&c.snapshot.size, snapshotSize)
// Save the size of the snapshot on the live cache
atomic.StoreUint64(&c.snapshotSize, snapshotSize)
// Reset the cache's store.
c.store.reset()
atomic.StoreUint64(&c.size, 0)
c.lastSnapshot = time.Now()
c.updateCachedBytes(snapshotSize) // increment the number of bytes added to the snapshot
c.updateSnapshots()
return c.snapshot, nil
}
// Deduplicate sorts the snapshot before returning it. The compactor and any queries
// coming in while it writes will need the values sorted.
func (c *Cache) Deduplicate() {
c.mu.RLock()
store := c.store
c.mu.RUnlock()
// Apply a function that simply calls deduplicate on each entry in the ring.
// apply cannot return an error in this invocation.
_ = store.apply(func(_ string, e *entry) error { e.deduplicate(); return nil })
}
// ClearSnapshot removes the snapshot cache from the list of flushing caches and
// adjusts the size.
func (c *Cache) ClearSnapshot(success bool) {
c.mu.Lock()
defer c.mu.Unlock()
c.snapshotting = false
if success {
c.snapshotAttempts = 0
c.updateMemSize(-int64(atomic.LoadUint64(&c.snapshotSize))) // decrement the number of bytes in cache
// Reset the snapshot's store, and reset the snapshot to a fresh Cache.
c.snapshot.store.reset()
c.snapshot = &Cache{
store: c.snapshot.store,
}
atomic.StoreUint64(&c.snapshotSize, 0)
c.updateSnapshots()
}
}
// Size returns the number of point-calcuated bytes the cache currently uses.
func (c *Cache) Size() uint64 {
return atomic.LoadUint64(&c.size)
}
// increaseSize increases size by delta.
func (c *Cache) increaseSize(delta uint64) {
atomic.AddUint64(&c.size, delta)
}
// decreaseSize decreases size by delta.
func (c *Cache) decreaseSize(delta uint64) {
// Per sync/atomic docs, bit-flip delta minus one to perform subtraction within AddUint64.
atomic.AddUint64(&c.size, ^(delta - 1))
}
// MaxSize returns the maximum number of bytes the cache may consume.
func (c *Cache) MaxSize() uint64 {
return c.maxSize
}
// Keys returns a sorted slice of all keys under management by the cache.
func (c *Cache) Keys() []string {
c.mu.RLock()
store := c.store
c.mu.RUnlock()
return store.keys(true)
}
// unsortedKeys returns a slice of all keys under management by the cache. The
// keys are not sorted.
func (c *Cache) unsortedKeys() []string {
c.mu.RLock()
store := c.store
c.mu.RUnlock()
return store.keys(false)
}
// Values returns a copy of all values, deduped and sorted, for the given key.
func (c *Cache) Values(key string) Values {
var snapshotEntries *entry
c.mu.RLock()
e, ok := c.store.entry(key)
if c.snapshot != nil {
snapshotEntries, _ = c.snapshot.store.entry(key)
}
c.mu.RUnlock()
if !ok {
if snapshotEntries == nil {
// No values in hot cache or snapshots.
return nil
}
} else {
e.deduplicate()
}
// Build the sequence of entries that will be returned, in the correct order.
// Calculate the required size of the destination buffer.
var entries []*entry
sz := 0
if snapshotEntries != nil {
snapshotEntries.deduplicate() // guarantee we are deduplicated
entries = append(entries, snapshotEntries)
sz += snapshotEntries.count()
}
if e != nil {
entries = append(entries, e)
sz += e.count()
}
// Any entries? If not, return.
if sz == 0 {
return nil
}
// Create the buffer, and copy all hot values and snapshots. Individual
// entries are sorted at this point, so now the code has to check if the
// resultant buffer will be sorted from start to finish.
values := make(Values, sz)
n := 0
for _, e := range entries {
e.mu.RLock()
n += copy(values[n:], e.values)
e.mu.RUnlock()
}
values = values[:n]
values = values.Deduplicate()
return values
}
// Delete removes all values for the given keys from the cache.
func (c *Cache) Delete(keys []string) {
c.DeleteRange(keys, math.MinInt64, math.MaxInt64)
}
// DeleteRange removes the values for all keys containing points
// with timestamps between between min and max from the cache.
//
// TODO(edd): Lock usage could possibly be optimised if necessary.
func (c *Cache) DeleteRange(keys []string, min, max int64) {
c.mu.Lock()
defer c.mu.Unlock()
for _, k := range keys {
// Make sure key exist in the cache, skip if it does not
e, ok := c.store.entry(k)
if !ok {
continue
}
origSize := uint64(e.size())
if min == math.MinInt64 && max == math.MaxInt64 {
c.decreaseSize(origSize)
c.store.remove(k)
continue
}
e.filter(min, max)
if e.count() == 0 {
c.store.remove(k)
c.decreaseSize(origSize)
continue
}
c.decreaseSize(origSize - uint64(e.size()))
}
atomic.StoreInt64(&c.stats.MemSizeBytes, int64(c.Size()))
}
// SetMaxSize updates the memory limit of the cache.
func (c *Cache) SetMaxSize(size uint64) {
c.mu.Lock()
c.maxSize = size
c.mu.Unlock()
}
// values returns the values for the key. It assumes the data is already sorted.
// It doesn't lock the cache but it does read-lock the entry if there is one for the key.
// values should only be used in compact.go in the CacheKeyIterator.
func (c *Cache) values(key string) Values {
e, _ := c.store.entry(key)
if e == nil {
return nil
}
e.mu.RLock()
v := e.values
e.mu.RUnlock()
return v
}
// ApplyEntryFn applies the function f to each entry in the Cache.
// ApplyEntryFn calls f on each entry in turn, within the same goroutine.
// It is safe for use by multiple goroutines.
func (c *Cache) ApplyEntryFn(f func(key string, entry *entry) error) error {
c.mu.RLock()
store := c.store
c.mu.RUnlock()
return store.applySerial(f)
}
// CacheLoader processes a set of WAL segment files, and loads a cache with the data
// contained within those files. Processing of the supplied files take place in the
// order they exist in the files slice.
type CacheLoader struct {
files []string
Logger zap.Logger
}
// NewCacheLoader returns a new instance of a CacheLoader.
func NewCacheLoader(files []string) *CacheLoader {
return &CacheLoader{
files: files,
Logger: zap.New(zap.NullEncoder()),
}
}
// Load returns a cache loaded with the data contained within the segment files.
// If, during reading of a segment file, corruption is encountered, that segment
// file is truncated up to and including the last valid byte, and processing
// continues with the next segment file.
func (cl *CacheLoader) Load(cache *Cache) error {
for _, fn := range cl.files {
if err := func() error {
f, err := os.OpenFile(fn, os.O_CREATE|os.O_RDWR, 0666)
if err != nil {
return err
}
// Log some information about the segments.
stat, err := os.Stat(f.Name())
if err != nil {
return err
}
cl.Logger.Info(fmt.Sprintf("reading file %s, size %d", f.Name(), stat.Size()))
r := NewWALSegmentReader(f)
defer r.Close()
for r.Next() {
entry, err := r.Read()
if err != nil {
n := r.Count()
cl.Logger.Info(fmt.Sprintf("file %s corrupt at position %d, truncating", f.Name(), n))
if err := f.Truncate(n); err != nil {
return err
}
break
}
switch t := entry.(type) {
case *WriteWALEntry:
if err := cache.WriteMulti(t.Values); err != nil {
return err
}
case *DeleteRangeWALEntry:
cache.DeleteRange(t.Keys, t.Min, t.Max)
case *DeleteWALEntry:
cache.Delete(t.Keys)
}
}
return nil
}(); err != nil {
return err
}
}
return nil
}
// WithLogger sets the logger on the CacheLoader.
func (cl *CacheLoader) WithLogger(log zap.Logger) {
cl.Logger = log.With(zap.String("service", "cacheloader"))
}
// UpdateAge updates the age statistic based on the current time.
func (c *Cache) UpdateAge() {
c.mu.RLock()
defer c.mu.RUnlock()
ageStat := int64(time.Since(c.lastSnapshot) / time.Millisecond)
atomic.StoreInt64(&c.stats.CacheAgeMs, ageStat)
}
// UpdateCompactTime updates WAL compaction time statistic based on d.
func (c *Cache) UpdateCompactTime(d time.Duration) {
atomic.AddInt64(&c.stats.WALCompactionTimeMs, int64(d/time.Millisecond))
}
// updateCachedBytes increases the cachedBytes counter by b.
func (c *Cache) updateCachedBytes(b uint64) {
atomic.AddInt64(&c.stats.CachedBytes, int64(b))
}
// updateMemSize updates the memSize level by b.
func (c *Cache) updateMemSize(b int64) {
atomic.AddInt64(&c.stats.MemSizeBytes, b)
}
func valueType(v Value) int {
switch v.(type) {
case FloatValue:
return 1
case IntegerValue:
return 2
case StringValue:
return 3
case BooleanValue:
return 4
default:
return 0
}
}
// updateSnapshots updates the snapshotsCount and the diskSize levels.
func (c *Cache) updateSnapshots() {
// Update disk stats
atomic.StoreInt64(&c.stats.DiskSizeBytes, int64(atomic.LoadUint64(&c.snapshotSize)))
atomic.StoreInt64(&c.stats.SnapshotCount, int64(c.snapshotAttempts))
}