Line data Source code
1 : // Copyright 2021 The LevelDB-Go and Pebble Authors. All rights reserved. Use
2 : // of this source code is governed by a BSD-style license that can be found in
3 : // the LICENSE file.
4 :
5 : package pebble
6 :
7 : import (
8 : "fmt"
9 : "strconv"
10 :
11 : "github.com/cockroachdb/errors"
12 : "github.com/cockroachdb/pebble/internal/manifest"
13 : "github.com/cockroachdb/pebble/sstable"
14 : "github.com/cockroachdb/pebble/vfs"
15 : "github.com/cockroachdb/pebble/vfs/atomicfs"
16 : )
17 :
18 : // FormatMajorVersion is a constant controlling the format of persisted
19 : // data. Backwards incompatible changes to durable formats are gated
20 : // behind new format major versions.
21 : //
22 : // At any point, a database's format major version may be bumped.
23 : // However, once a database's format major version is increased,
24 : // previous versions of Pebble will refuse to open the database.
25 : //
26 : // The zero value format is the FormatDefault constant. The exact
27 : // FormatVersion that the default corresponds to may change with time.
28 : type FormatMajorVersion uint64
29 :
30 : // SafeValue implements redact.SafeValue.
31 0 : func (v FormatMajorVersion) SafeValue() {}
32 :
33 : // String implements fmt.Stringer.
34 1 : func (v FormatMajorVersion) String() string {
35 1 : // NB: This must not change. It's used as the value for the on-disk
36 1 : // version marker file.
37 1 : //
38 1 : // Specifically, this value must always parse as a base 10 integer
39 1 : // that fits in a uint64. We format it as zero-padded, 3-digit
40 1 : // number today, but the padding may change.
41 1 : return fmt.Sprintf("%03d", v)
42 1 : }
43 :
44 : const (
45 : // FormatDefault leaves the format version unspecified. When used to create a
46 : // new store, Pebble will choose the earliest format version it supports.
47 : FormatDefault FormatMajorVersion = iota
48 :
49 : // 21.2 versions.
50 :
51 : // FormatMostCompatible maintains the most backwards compatibility,
52 : // maintaining bi-directional compatibility with RocksDB 6.2.1 in
53 : // the particular configuration described in the Pebble README.
54 : // Deprecated.
55 : _ // FormatMostCompatible
56 :
57 : // formatVersionedManifestMarker is the first
58 : // backwards-incompatible change made to Pebble, introducing the
59 : // format-version marker file for handling backwards-incompatible
60 : // changes more broadly, and replacing the `CURRENT` file with a
61 : // marker file.
62 : //
63 : // This format version is intended as an intermediary version state.
64 : // It is deliberately unexported to discourage direct use of this
65 : // format major version. Clients should use FormatVersioned which
66 : // also ensures earlier versions of Pebble fail to open a database
67 : // written in a future format major version.
68 : // Deprecated.
69 : _ // formatVersionedManifestMarker
70 :
71 : // FormatVersioned is a new format major version that replaces the
72 : // old `CURRENT` file with a new 'marker' file scheme. Previous
73 : // Pebble versions will be unable to open the database unless
74 : // they're aware of format versions.
75 : // Deprecated.
76 : _ // FormatVersioned
77 :
78 : // FormatSetWithDelete is a format major version that introduces a new key
79 : // kind, base.InternalKeyKindSetWithDelete. Previous Pebble versions will be
80 : // unable to open this database.
81 : // Deprecated.
82 : _ // FormatSetWithDelete
83 :
84 : // 22.1 versions.
85 :
86 : // FormatBlockPropertyCollector is a format major version that introduces
87 : // BlockPropertyCollectors.
88 : // Deprecated.
89 : _ // FormatBlockPropertyCollector
90 :
91 : // FormatSplitUserKeysMarked is a format major version that guarantees that
92 : // all files that share user keys with neighbors are marked for compaction
93 : // in the manifest. Ratcheting to FormatSplitUserKeysMarked will block
94 : // (without holding mutexes) until the scan of the LSM is complete and the
95 : // manifest has been rotated.
96 : // Deprecated.
97 : _ // FormatSplitUserKeysMarked
98 :
99 : // 22.2 versions.
100 :
101 : // FormatSplitUserKeysMarkedCompacted is a format major version that
102 : // guarantees that all files explicitly marked for compaction in the manifest
103 : // have been compacted. Combined with the FormatSplitUserKeysMarked format
104 : // major version, this version guarantees that there are no user keys split
105 : // across multiple files within a level L1+. Ratcheting to this format version
106 : // will block (without holding mutexes) until all necessary compactions for
107 : // files marked for compaction are complete.
108 : // Deprecated.
109 : _ // FormatSplitUserKeysMarkedCompacted
110 :
111 : // FormatRangeKeys is a format major version that introduces range keys.
112 : // Deprecated.
113 : _ // FormatRangeKeys
114 :
115 : // FormatMinTableFormatPebblev1 is a format major version that guarantees that
116 : // tables created by or ingested into the DB at or above this format major
117 : // version will have a table format version of at least Pebblev1 (Block
118 : // Properties).
119 : // Deprecated.
120 : _ // FormatMinTableFormatPebblev1
121 :
122 : // FormatPrePebblev1Marked is a format major version that guarantees that all
123 : // sstables with a table format version pre-Pebblev1 (i.e. those that are
124 : // guaranteed to not contain block properties) are marked for compaction in
125 : // the manifest. Ratcheting to FormatPrePebblev1Marked will block (without
126 : // holding mutexes) until the scan of the LSM is complete and the manifest has
127 : // been rotated.
128 : // Deprecated.
129 : _ // FormatPrePebblev1Marked
130 :
131 : // 23.1 versions.
132 :
133 : // formatUnusedPrePebblev1MarkedCompacted is an unused format major version.
134 : // This format major version was originally intended to ship in the 23.1
135 : // release. It was later decided that this should be deferred until a
136 : // subsequent release. The original ordering is preserved so as not to
137 : // introduce breaking changes in Cockroach.
138 : _ // formatUnusedPrePebblev1MarkedCompacted
139 :
140 : // FormatSSTableValueBlocks is a format major version that adds support for
141 : // storing values in value blocks in the sstable. Value block support is not
142 : // necessarily enabled when writing sstables, when running with this format
143 : // major version.
144 : _ // FormatSSTableValueBlocks
145 :
146 : // FormatFlushableIngest is a format major version that enables lazy
147 : // addition of ingested sstables into the LSM structure. When an ingest
148 : // overlaps with a memtable, a record of the ingest is written to the WAL
149 : // without waiting for a flush. Subsequent reads treat the ingested files as
150 : // a level above the overlapping memtable. Once the memtable is flushed, the
151 : // ingested files are moved into the lowest possible levels.
152 : //
153 : // This feature is behind a format major version because it required
154 : // breaking changes to the WAL format.
155 : FormatFlushableIngest
156 :
157 : // 23.2 versions.
158 :
159 : // FormatPrePebblev1MarkedCompacted is a format major version that guarantees
160 : // that all sstables explicitly marked for compaction in the manifest (see
161 : // FormatPrePebblev1Marked) have been compacted. Ratcheting to this format
162 : // version will block (without holding mutexes) until all necessary
163 : // compactions for files marked for compaction are complete.
164 : FormatPrePebblev1MarkedCompacted
165 :
166 : // FormatDeleteSizedAndObsolete is a format major version that adds support
167 : // for deletion tombstones that encode the size of the value they're
168 : // expected to delete. This format major version is required before the
169 : // associated key kind may be committed through batch applications or
170 : // ingests. It also adds support for keys that are marked obsolete (see
171 : // sstable/format.go for details).
172 : FormatDeleteSizedAndObsolete
173 :
174 : // FormatVirtualSSTables is a format major version that adds support for
175 : // virtual sstables that can reference a sub-range of keys in an underlying
176 : // physical sstable. This information is persisted through new,
177 : // backward-incompatible fields in the Manifest, and therefore requires
178 : // a format major version.
179 : FormatVirtualSSTables
180 :
181 : // FormatSyntheticPrefixSuffix is a format major version that adds support for
182 : // sstables to have their content exposed in a different prefix or suffix of
183 : // keyspace than the actual prefix/suffix persisted in the keys in such
184 : // sstables. The prefix and suffix replacement information is stored in new
185 : // fields in the Manifest and thus requires a format major version.
186 : FormatSyntheticPrefixSuffix
187 :
188 : // TODO(msbutler): add major version for synthetic suffixes
189 :
190 : // -- Add new versions here --
191 :
192 : // FormatNewest is the most recent format major version.
193 : FormatNewest FormatMajorVersion = iota - 1
194 :
195 : // Experimental versions, which are excluded by FormatNewest (but can be used
196 : // in tests) can be defined here.
197 :
198 : // -- Add experimental versions here --
199 :
200 : // internalFormatNewest is the most recent, possibly experimental format major
201 : // version.
202 : internalFormatNewest FormatMajorVersion = iota - 2
203 : )
204 :
205 : // FormatMinSupported is the minimum format version that is supported by this
206 : // Pebble version.
207 : const FormatMinSupported = FormatFlushableIngest
208 :
209 : // FormatMinForSharedObjects it the minimum format version that supports shared
210 : // objects (see CreateOnShared option).
211 : const FormatMinForSharedObjects = FormatVirtualSSTables
212 :
213 : // IsSupported returns true if the version is supported by the current Pebble
214 : // version.
215 0 : func (v FormatMajorVersion) IsSupported() bool {
216 0 : return v == FormatDefault && v >= FormatMinSupported && v <= internalFormatNewest
217 0 : }
218 :
219 : // MaxTableFormat returns the maximum sstable.TableFormat that can be used at
220 : // this FormatMajorVersion.
221 1 : func (v FormatMajorVersion) MaxTableFormat() sstable.TableFormat {
222 1 : switch v {
223 1 : case FormatDefault, FormatFlushableIngest, FormatPrePebblev1MarkedCompacted:
224 1 : return sstable.TableFormatPebblev3
225 1 : case FormatDeleteSizedAndObsolete, FormatVirtualSSTables, FormatSyntheticPrefixSuffix:
226 1 : return sstable.TableFormatPebblev4
227 1 : default:
228 1 : panic(fmt.Sprintf("pebble: unsupported format major version: %s", v))
229 : }
230 : }
231 :
232 : // MinTableFormat returns the minimum sstable.TableFormat that can be used at
233 : // this FormatMajorVersion.
234 1 : func (v FormatMajorVersion) MinTableFormat() sstable.TableFormat {
235 1 : switch v {
236 : case FormatDefault, FormatFlushableIngest, FormatPrePebblev1MarkedCompacted,
237 1 : FormatDeleteSizedAndObsolete, FormatVirtualSSTables, FormatSyntheticPrefixSuffix:
238 1 : return sstable.TableFormatPebblev1
239 1 : default:
240 1 : panic(fmt.Sprintf("pebble: unsupported format major version: %s", v))
241 : }
242 : }
243 :
244 : // formatMajorVersionMigrations defines the migrations from one format
245 : // major version to the next. Each migration is defined as a closure
246 : // which will be invoked on the database before the new format major
247 : // version is committed. Migrations must be idempotent. Migrations are
248 : // invoked with d.mu locked.
249 : //
250 : // Each migration is responsible for invoking finalizeFormatVersUpgrade
251 : // to set the new format major version. RatchetFormatMajorVersion will
252 : // panic if a migration returns a nil error but fails to finalize the
253 : // new format major version.
254 : var formatMajorVersionMigrations = map[FormatMajorVersion]func(*DB) error{
255 0 : FormatFlushableIngest: func(d *DB) error { return nil },
256 1 : FormatPrePebblev1MarkedCompacted: func(d *DB) error {
257 1 : // Before finalizing the format major version, rewrite any sstables
258 1 : // still marked for compaction. Note all format major versions
259 1 : // migrations are invoked with DB.mu locked.
260 1 : if err := d.compactMarkedFilesLocked(); err != nil {
261 0 : return err
262 0 : }
263 1 : return d.finalizeFormatVersUpgrade(FormatPrePebblev1MarkedCompacted)
264 : },
265 1 : FormatDeleteSizedAndObsolete: func(d *DB) error {
266 1 : return d.finalizeFormatVersUpgrade(FormatDeleteSizedAndObsolete)
267 1 : },
268 1 : FormatVirtualSSTables: func(d *DB) error {
269 1 : return d.finalizeFormatVersUpgrade(FormatVirtualSSTables)
270 1 : },
271 1 : FormatSyntheticPrefixSuffix: func(d *DB) error {
272 1 : return d.finalizeFormatVersUpgrade(FormatSyntheticPrefixSuffix)
273 1 : },
274 : }
275 :
276 : const formatVersionMarkerName = `format-version`
277 :
278 : // lookupFormatMajorVersion retrieves the format version from the format version
279 : // marker file.
280 : //
281 : // If such a file does not exist, returns FormatDefault. Note that this case is
282 : // only acceptable if we are creating a new store (we no longer support
283 : // FormatMostCompatible which is the only one with no version marker file).
284 : func lookupFormatMajorVersion(
285 : fs vfs.FS, dirname string,
286 1 : ) (FormatMajorVersion, *atomicfs.Marker, error) {
287 1 : m, versString, err := atomicfs.LocateMarker(fs, dirname, formatVersionMarkerName)
288 1 : if err != nil {
289 1 : return 0, nil, err
290 1 : }
291 1 : if versString == "" {
292 1 : return FormatDefault, m, nil
293 1 : }
294 1 : v, err := strconv.ParseUint(versString, 10, 64)
295 1 : if err != nil {
296 0 : return 0, nil, errors.Wrap(err, "parsing format major version")
297 0 : }
298 1 : vers := FormatMajorVersion(v)
299 1 : if vers == FormatDefault {
300 0 : return 0, nil, errors.Newf("pebble: default format major version should not persisted", vers)
301 0 : }
302 1 : if vers > internalFormatNewest {
303 1 : return 0, nil, errors.Newf("pebble: database %q written in unknown format major version %d", dirname, vers)
304 1 : }
305 1 : if vers < FormatMinSupported {
306 0 : return 0, nil, errors.Newf("pebble: database %q written in format major version %d which is no longer supported", dirname, vers)
307 0 : }
308 1 : return vers, m, nil
309 : }
310 :
311 : // FormatMajorVersion returns the database's active format major
312 : // version. The format major version may be higher than the one
313 : // provided in Options when the database was opened if the existing
314 : // database was written with a higher format version.
315 1 : func (d *DB) FormatMajorVersion() FormatMajorVersion {
316 1 : return FormatMajorVersion(d.mu.formatVers.vers.Load())
317 1 : }
318 :
319 : // RatchetFormatMajorVersion ratchets the opened database's format major
320 : // version to the provided version. It errors if the provided format
321 : // major version is below the database's current version. Once a
322 : // database's format major version is upgraded, previous Pebble versions
323 : // that do not know of the format version will be unable to open the
324 : // database.
325 1 : func (d *DB) RatchetFormatMajorVersion(fmv FormatMajorVersion) error {
326 1 : if err := d.closed.Load(); err != nil {
327 1 : panic(err)
328 : }
329 :
330 1 : d.mu.Lock()
331 1 : defer d.mu.Unlock()
332 1 : return d.ratchetFormatMajorVersionLocked(fmv)
333 : }
334 :
335 1 : func (d *DB) ratchetFormatMajorVersionLocked(formatVers FormatMajorVersion) error {
336 1 : if d.opts.ReadOnly {
337 0 : return ErrReadOnly
338 0 : }
339 1 : if formatVers > internalFormatNewest {
340 0 : // Guard against accidentally forgetting to update internalFormatNewest.
341 0 : return errors.Errorf("pebble: unknown format version %d", formatVers)
342 0 : }
343 1 : if currentVers := d.FormatMajorVersion(); currentVers > formatVers {
344 0 : return errors.Newf("pebble: database already at format major version %d; cannot reduce to %d",
345 0 : currentVers, formatVers)
346 0 : }
347 1 : if d.mu.formatVers.ratcheting {
348 0 : return errors.Newf("pebble: database format major version upgrade is in-progress")
349 0 : }
350 1 : d.mu.formatVers.ratcheting = true
351 1 : defer func() { d.mu.formatVers.ratcheting = false }()
352 :
353 1 : for nextVers := d.FormatMajorVersion() + 1; nextVers <= formatVers; nextVers++ {
354 1 : if err := formatMajorVersionMigrations[nextVers](d); err != nil {
355 0 : return errors.Wrapf(err, "migrating to version %d", nextVers)
356 0 : }
357 :
358 : // NB: The migration is responsible for calling
359 : // finalizeFormatVersUpgrade to finalize the upgrade. This
360 : // structure is necessary because some migrations may need to
361 : // update in-memory state (without ever dropping locks) after
362 : // the upgrade is finalized. Here we assert that the upgrade
363 : // did occur.
364 1 : if d.FormatMajorVersion() != nextVers {
365 0 : d.opts.Logger.Fatalf("pebble: successful migration to format version %d never finalized the upgrade", nextVers)
366 0 : }
367 : }
368 1 : return nil
369 : }
370 :
371 : // finalizeFormatVersUpgrade is typically only be called from within a
372 : // format major version migration.
373 : //
374 : // See formatMajorVersionMigrations.
375 1 : func (d *DB) finalizeFormatVersUpgrade(formatVers FormatMajorVersion) error {
376 1 : if err := d.writeFormatVersionMarker(formatVers); err != nil {
377 0 : return err
378 0 : }
379 1 : d.mu.formatVers.vers.Store(uint64(formatVers))
380 1 : d.opts.EventListener.FormatUpgrade(formatVers)
381 1 : return nil
382 : }
383 :
384 1 : func (d *DB) writeFormatVersionMarker(formatVers FormatMajorVersion) error {
385 1 : // We use the marker to encode the active format version in the
386 1 : // marker filename. Unlike other uses of the atomic marker, there is
387 1 : // no file with the filename `formatVers.String()` on the
388 1 : // filesystem.
389 1 : return d.mu.formatVers.marker.Move(formatVers.String())
390 1 : }
391 :
392 : // compactMarkedFilesLocked performs a migration that schedules rewrite
393 : // compactions to compact away any sstables marked for compaction.
394 : // compactMarkedFilesLocked is run while ratcheting the database's format major
395 : // version to FormatSplitUserKeysMarkedCompacted.
396 : //
397 : // Note that while this method is called with the DB.mu held, and will not
398 : // return until all marked files have been compacted, the mutex is dropped while
399 : // waiting for compactions to complete (or for slots to free up).
400 1 : func (d *DB) compactMarkedFilesLocked() error {
401 1 : curr := d.mu.versions.currentVersion()
402 1 : for curr.Stats.MarkedForCompaction > 0 {
403 0 : // Attempt to schedule a compaction to rewrite a file marked for
404 0 : // compaction.
405 0 : d.maybeScheduleCompactionPicker(func(picker compactionPicker, env compactionEnv) *pickedCompaction {
406 0 : return picker.pickRewriteCompaction(env)
407 0 : })
408 :
409 : // The above attempt might succeed and schedule a rewrite compaction. Or
410 : // there might not be available compaction concurrency to schedule the
411 : // compaction. Or compaction of the file might have already been in
412 : // progress. In any scenario, wait until there's some change in the
413 : // state of active compactions.
414 :
415 : // Before waiting, check that the database hasn't been closed. Trying to
416 : // schedule the compaction may have dropped d.mu while waiting for a
417 : // manifest write to complete. In that dropped interim, the database may
418 : // have been closed.
419 0 : if err := d.closed.Load(); err != nil {
420 0 : return err.(error)
421 0 : }
422 :
423 : // Some flush or compaction may have scheduled or completed while we waited
424 : // for the manifest lock in maybeScheduleCompactionPicker. Get the latest
425 : // Version before waiting on a compaction.
426 0 : curr = d.mu.versions.currentVersion()
427 0 :
428 0 : // Only wait on compactions if there are files still marked for compaction.
429 0 : // NB: Waiting on this condition variable drops d.mu while blocked.
430 0 : if curr.Stats.MarkedForCompaction > 0 {
431 0 : if d.mu.compact.compactingCount == 0 {
432 0 : panic("expected a compaction of marked files in progress")
433 : }
434 0 : d.mu.compact.cond.Wait()
435 0 : // Refresh the current version again.
436 0 : curr = d.mu.versions.currentVersion()
437 : }
438 : }
439 1 : return nil
440 : }
441 :
442 : // findFilesFunc scans the LSM for files, returning true if at least one
443 : // file was found. The returned array contains the matched files, if any, per
444 : // level.
445 : type findFilesFunc func(v *version) (found bool, files [numLevels][]*fileMetadata, _ error)
446 :
447 : // This method is not used currently, but it will be useful the next time we need
448 : // to mark files for compaction.
449 : var _ = (*DB)(nil).markFilesLocked
450 :
451 : // markFilesLocked durably marks the files that match the given findFilesFunc for
452 : // compaction.
453 0 : func (d *DB) markFilesLocked(findFn findFilesFunc) error {
454 0 : jobID := d.mu.nextJobID
455 0 : d.mu.nextJobID++
456 0 :
457 0 : // Acquire a read state to have a view of the LSM and a guarantee that none
458 0 : // of the referenced files will be deleted until we've unreferenced the read
459 0 : // state. Some findFilesFuncs may read the files, requiring they not be
460 0 : // deleted.
461 0 : rs := d.loadReadState()
462 0 : var (
463 0 : found bool
464 0 : files [numLevels][]*fileMetadata
465 0 : err error
466 0 : )
467 0 : func() {
468 0 : defer rs.unrefLocked()
469 0 : // Note the unusual locking: unlock, defer Lock(). The scan of the files in
470 0 : // the version does not need to block other operations that require the
471 0 : // DB.mu. Drop it for the scan, before re-acquiring it.
472 0 : d.mu.Unlock()
473 0 : defer d.mu.Lock()
474 0 : found, files, err = findFn(rs.current)
475 0 : }()
476 0 : if err != nil {
477 0 : return err
478 0 : }
479 :
480 : // The database lock has been acquired again by the defer within the above
481 : // anonymous function.
482 0 : if !found {
483 0 : // Nothing to do.
484 0 : return nil
485 0 : }
486 :
487 : // After scanning, if we found files to mark, we fetch the current state of
488 : // the LSM (which may have changed) and set MarkedForCompaction on the files,
489 : // and update the version's Stats.MarkedForCompaction count, which are both
490 : // protected by d.mu.
491 :
492 : // Lock the manifest for a coherent view of the LSM. The database lock has
493 : // been re-acquired by the defer within the above anonymous function.
494 0 : d.mu.versions.logLock()
495 0 : vers := d.mu.versions.currentVersion()
496 0 : for l, filesToMark := range files {
497 0 : if len(filesToMark) == 0 {
498 0 : continue
499 : }
500 0 : for _, f := range filesToMark {
501 0 : // Ignore files to be marked that have already been compacted or marked.
502 0 : if f.CompactionState == manifest.CompactionStateCompacted ||
503 0 : f.MarkedForCompaction {
504 0 : continue
505 : }
506 : // Else, mark the file for compaction in this version.
507 0 : vers.Stats.MarkedForCompaction++
508 0 : f.MarkedForCompaction = true
509 : }
510 : // The compaction picker uses the markedForCompactionAnnotator to
511 : // quickly find files marked for compaction, or to quickly determine
512 : // that there are no such files marked for compaction within a level.
513 : // A b-tree node may be annotated with an annotation recording that
514 : // there are no files marked for compaction within the node's subtree,
515 : // based on the assumption that it's static.
516 : //
517 : // Since we're marking files for compaction, these b-tree nodes'
518 : // annotations will be out of date. Clear the compaction-picking
519 : // annotation, so that it's recomputed the next time the compaction
520 : // picker looks for a file marked for compaction.
521 0 : vers.Levels[l].InvalidateAnnotation(markedForCompactionAnnotator{})
522 : }
523 :
524 : // The 'marked-for-compaction' bit is persisted in the MANIFEST file
525 : // metadata. We've already modified the in-memory file metadata, but the
526 : // manifest hasn't been updated. Force rotation to a new MANIFEST file,
527 : // which will write every file metadata to the new manifest file and ensure
528 : // that the now marked-for-compaction file metadata are persisted as marked.
529 : // NB: This call to logAndApply will unlockthe MANIFEST, which we locked up
530 : // above before obtaining `vers`.
531 0 : return d.mu.versions.logAndApply(
532 0 : jobID,
533 0 : &manifest.VersionEdit{},
534 0 : map[int]*LevelMetrics{},
535 0 : true, /* forceRotation */
536 0 : func() []compactionInfo { return d.getInProgressCompactionInfoLocked(nil) })
537 : }
|
