ceremonyclient/pebble/version_set.go

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2024-01-03 07:31:42 +00:00
// Copyright 2012 The LevelDB-Go and Pebble Authors. All rights reserved. Use
// of this source code is governed by a BSD-style license that can be found in
// the LICENSE file.
package pebble
import (
"bytes"
"fmt"
"io"
"sync"
"sync/atomic"
"github.com/cockroachdb/errors"
"github.com/cockroachdb/errors/oserror"
"github.com/cockroachdb/pebble/internal/base"
"github.com/cockroachdb/pebble/internal/invariants"
"github.com/cockroachdb/pebble/internal/manifest"
"github.com/cockroachdb/pebble/record"
"github.com/cockroachdb/pebble/vfs"
"github.com/cockroachdb/pebble/vfs/atomicfs"
)
const numLevels = manifest.NumLevels
const manifestMarkerName = `manifest`
// Provide type aliases for the various manifest structs.
type bulkVersionEdit = manifest.BulkVersionEdit
type deletedFileEntry = manifest.DeletedFileEntry
type fileMetadata = manifest.FileMetadata
type physicalMeta = manifest.PhysicalFileMeta
type virtualMeta = manifest.VirtualFileMeta
type fileBacking = manifest.FileBacking
type newFileEntry = manifest.NewFileEntry
type version = manifest.Version
type versionEdit = manifest.VersionEdit
type versionList = manifest.VersionList
// versionSet manages a collection of immutable versions, and manages the
// creation of a new version from the most recent version. A new version is
// created from an existing version by applying a version edit which is just
// like it sounds: a delta from the previous version. Version edits are logged
// to the MANIFEST file, which is replayed at startup.
type versionSet struct {
// Next seqNum to use for WAL writes.
logSeqNum atomic.Uint64
// The upper bound on sequence numbers that have been assigned so far. A
// suffix of these sequence numbers may not have been written to a WAL. Both
// logSeqNum and visibleSeqNum are atomically updated by the commitPipeline.
// visibleSeqNum is <= logSeqNum.
visibleSeqNum atomic.Uint64
// Number of bytes present in sstables being written by in-progress
// compactions. This value will be zero if there are no in-progress
// compactions. Updated and read atomically.
atomicInProgressBytes atomic.Int64
// Immutable fields.
dirname string
// Set to DB.mu.
mu *sync.Mutex
opts *Options
fs vfs.FS
cmp Compare
cmpName string
// Dynamic base level allows the dynamic base level computation to be
// disabled. Used by tests which want to create specific LSM structures.
dynamicBaseLevel bool
// Mutable fields.
versions versionList
picker compactionPicker
metrics Metrics
// A pointer to versionSet.addObsoleteLocked. Avoids allocating a new closure
// on the creation of every version.
obsoleteFn func(obsolete []*fileBacking)
obsoleteTables []fileInfo
obsoleteManifests []fileInfo
obsoleteOptions []fileInfo
// Zombie tables which have been removed from the current version but are
// still referenced by an inuse iterator.
zombieTables map[base.DiskFileNum]uint64 // filenum -> size
// backingState is protected by the versionSet.logLock. It's populated
// during Open in versionSet.load, but it's not used concurrently during
// load.
backingState struct {
// fileBackingMap is a map for the FileBacking which is supporting virtual
// sstables in the latest version. Once the file backing is backing no
// virtual sstables in the latest version, it is removed from this map and
// the corresponding state is added to the zombieTables map. Note that we
// don't keep track of file backing which supports a virtual sstable
// which is not in the latest version.
fileBackingMap map[base.DiskFileNum]*fileBacking
// fileBackingSize is the sum of the sizes of the fileBackings in the
// fileBackingMap.
fileBackingSize uint64
}
// minUnflushedLogNum is the smallest WAL log file number corresponding to
// mutations that have not been flushed to an sstable.
minUnflushedLogNum base.DiskFileNum
// The next file number. A single counter is used to assign file
// numbers for the WAL, MANIFEST, sstable, and OPTIONS files.
nextFileNum uint64
// The current manifest file number.
manifestFileNum base.DiskFileNum
manifestMarker *atomicfs.Marker
manifestFile vfs.File
manifest *record.Writer
setCurrent func(base.DiskFileNum) error
getFormatMajorVersion func() FormatMajorVersion
writing bool
writerCond sync.Cond
// State for deciding when to write a snapshot. Protected by mu.
rotationHelper record.RotationHelper
}
func (vs *versionSet) init(
dirname string,
opts *Options,
marker *atomicfs.Marker,
setCurrent func(base.DiskFileNum) error,
getFMV func() FormatMajorVersion,
mu *sync.Mutex,
) {
vs.dirname = dirname
vs.mu = mu
vs.writerCond.L = mu
vs.opts = opts
vs.fs = opts.FS
vs.cmp = opts.Comparer.Compare
vs.cmpName = opts.Comparer.Name
vs.dynamicBaseLevel = true
vs.versions.Init(mu)
vs.obsoleteFn = vs.addObsoleteLocked
vs.zombieTables = make(map[base.DiskFileNum]uint64)
vs.backingState.fileBackingMap = make(map[base.DiskFileNum]*fileBacking)
vs.backingState.fileBackingSize = 0
vs.nextFileNum = 1
vs.manifestMarker = marker
vs.setCurrent = setCurrent
vs.getFormatMajorVersion = getFMV
}
// create creates a version set for a fresh DB.
func (vs *versionSet) create(
jobID int,
dirname string,
opts *Options,
marker *atomicfs.Marker,
setCurrent func(base.DiskFileNum) error,
getFormatMajorVersion func() FormatMajorVersion,
mu *sync.Mutex,
) error {
vs.init(dirname, opts, marker, setCurrent, getFormatMajorVersion, mu)
newVersion := &version{}
vs.append(newVersion)
var err error
vs.picker = newCompactionPicker(newVersion, vs.opts, nil)
// Note that a "snapshot" version edit is written to the manifest when it is
// created.
vs.manifestFileNum = vs.getNextDiskFileNum()
err = vs.createManifest(vs.dirname, vs.manifestFileNum, vs.minUnflushedLogNum, vs.nextFileNum)
if err == nil {
if err = vs.manifest.Flush(); err != nil {
vs.opts.Logger.Fatalf("MANIFEST flush failed: %v", err)
}
}
if err == nil {
if err = vs.manifestFile.Sync(); err != nil {
vs.opts.Logger.Fatalf("MANIFEST sync failed: %v", err)
}
}
if err == nil {
// NB: setCurrent is responsible for syncing the data directory.
if err = vs.setCurrent(vs.manifestFileNum); err != nil {
vs.opts.Logger.Fatalf("MANIFEST set current failed: %v", err)
}
}
vs.opts.EventListener.ManifestCreated(ManifestCreateInfo{
JobID: jobID,
Path: base.MakeFilepath(vs.fs, vs.dirname, fileTypeManifest, vs.manifestFileNum),
FileNum: vs.manifestFileNum,
Err: err,
})
if err != nil {
return err
}
return nil
}
// load loads the version set from the manifest file.
func (vs *versionSet) load(
dirname string,
opts *Options,
manifestFileNum base.DiskFileNum,
marker *atomicfs.Marker,
setCurrent func(base.DiskFileNum) error,
getFormatMajorVersion func() FormatMajorVersion,
mu *sync.Mutex,
) error {
vs.init(dirname, opts, marker, setCurrent, getFormatMajorVersion, mu)
vs.manifestFileNum = manifestFileNum
manifestPath := base.MakeFilepath(opts.FS, dirname, fileTypeManifest, vs.manifestFileNum)
manifestFilename := opts.FS.PathBase(manifestPath)
// Read the versionEdits in the manifest file.
var bve bulkVersionEdit
bve.AddedByFileNum = make(map[base.FileNum]*fileMetadata)
manifest, err := vs.fs.Open(manifestPath)
if err != nil {
return errors.Wrapf(err, "pebble: could not open manifest file %q for DB %q",
errors.Safe(manifestFilename), dirname)
}
defer manifest.Close()
rr := record.NewReader(manifest, 0 /* logNum */)
for {
r, err := rr.Next()
if err == io.EOF || record.IsInvalidRecord(err) {
break
}
if err != nil {
return errors.Wrapf(err, "pebble: error when loading manifest file %q",
errors.Safe(manifestFilename))
}
var ve versionEdit
err = ve.Decode(r)
if err != nil {
// Break instead of returning an error if the record is corrupted
// or invalid.
if err == io.EOF || record.IsInvalidRecord(err) {
break
}
return err
}
if ve.ComparerName != "" {
if ve.ComparerName != vs.cmpName {
return errors.Errorf("pebble: manifest file %q for DB %q: "+
"comparer name from file %q != comparer name from Options %q",
errors.Safe(manifestFilename), dirname, errors.Safe(ve.ComparerName), errors.Safe(vs.cmpName))
}
}
if err := bve.Accumulate(&ve); err != nil {
return err
}
if ve.MinUnflushedLogNum != 0 {
vs.minUnflushedLogNum = ve.MinUnflushedLogNum
}
if ve.NextFileNum != 0 {
vs.nextFileNum = ve.NextFileNum
}
if ve.LastSeqNum != 0 {
// logSeqNum is the _next_ sequence number that will be assigned,
// while LastSeqNum is the last assigned sequence number. Note that
// this behaviour mimics that in RocksDB; the first sequence number
// assigned is one greater than the one present in the manifest
// (assuming no WALs contain higher sequence numbers than the
// manifest's LastSeqNum). Increment LastSeqNum by 1 to get the
// next sequence number that will be assigned.
//
// If LastSeqNum is less than SeqNumStart, increase it to at least
// SeqNumStart to leave ample room for reserved sequence numbers.
if ve.LastSeqNum+1 < base.SeqNumStart {
vs.logSeqNum.Store(base.SeqNumStart)
} else {
vs.logSeqNum.Store(ve.LastSeqNum + 1)
}
}
}
// We have already set vs.nextFileNum = 2 at the beginning of the
// function and could have only updated it to some other non-zero value,
// so it cannot be 0 here.
if vs.minUnflushedLogNum == 0 {
if vs.nextFileNum >= 2 {
// We either have a freshly created DB, or a DB created by RocksDB
// that has not had a single flushed SSTable yet. This is because
// RocksDB bumps up nextFileNum in this case without bumping up
// minUnflushedLogNum, even if WALs with non-zero file numbers are
// present in the directory.
} else {
return base.CorruptionErrorf("pebble: malformed manifest file %q for DB %q",
errors.Safe(manifestFilename), dirname)
}
}
vs.markFileNumUsed(vs.minUnflushedLogNum)
// Populate the fileBackingMap and the FileBacking for virtual sstables since
// we have finished version edit accumulation.
for _, s := range bve.AddedFileBacking {
vs.addFileBacking(s)
}
for _, fileNum := range bve.RemovedFileBacking {
vs.removeFileBacking(fileNum)
}
newVersion, err := bve.Apply(
nil, vs.cmp, opts.Comparer.FormatKey, opts.FlushSplitBytes,
opts.Experimental.ReadCompactionRate, nil, /* zombies */
getFormatMajorVersion().orderingInvariants(),
)
if err != nil {
return err
}
newVersion.L0Sublevels.InitCompactingFileInfo(nil /* in-progress compactions */)
vs.append(newVersion)
for i := range vs.metrics.Levels {
l := &vs.metrics.Levels[i]
l.NumFiles = int64(newVersion.Levels[i].Len())
files := newVersion.Levels[i].Slice()
l.Size = int64(files.SizeSum())
}
vs.picker = newCompactionPicker(newVersion, vs.opts, nil)
return nil
}
func (vs *versionSet) close() error {
if vs.manifestFile != nil {
if err := vs.manifestFile.Close(); err != nil {
return err
}
}
if vs.manifestMarker != nil {
if err := vs.manifestMarker.Close(); err != nil {
return err
}
}
return nil
}
// logLock locks the manifest for writing. The lock must be released by either
// a call to logUnlock or logAndApply.
//
// DB.mu must be held when calling this method, but the mutex may be dropped and
// re-acquired during the course of this method.
func (vs *versionSet) logLock() {
// Wait for any existing writing to the manifest to complete, then mark the
// manifest as busy.
for vs.writing {
vs.writerCond.Wait()
}
vs.writing = true
}
// logUnlock releases the lock for manifest writing.
//
// DB.mu must be held when calling this method.
func (vs *versionSet) logUnlock() {
if !vs.writing {
vs.opts.Logger.Fatalf("MANIFEST not locked for writing")
}
vs.writing = false
vs.writerCond.Signal()
}
// Only call if the DiskFileNum doesn't exist in the fileBackingMap.
func (vs *versionSet) addFileBacking(backing *manifest.FileBacking) {
_, ok := vs.backingState.fileBackingMap[backing.DiskFileNum]
if ok {
panic("pebble: trying to add an existing file backing")
}
vs.backingState.fileBackingMap[backing.DiskFileNum] = backing
vs.backingState.fileBackingSize += backing.Size
}
// Only call if the the DiskFileNum exists in the fileBackingMap.
func (vs *versionSet) removeFileBacking(dfn base.DiskFileNum) {
backing, ok := vs.backingState.fileBackingMap[dfn]
if !ok {
panic("pebble: trying to remove an unknown file backing")
}
delete(vs.backingState.fileBackingMap, dfn)
vs.backingState.fileBackingSize -= backing.Size
}
// logAndApply logs the version edit to the manifest, applies the version edit
// to the current version, and installs the new version.
//
// DB.mu must be held when calling this method and will be released temporarily
// while performing file I/O. Requires that the manifest is locked for writing
// (see logLock). Will unconditionally release the manifest lock (via
// logUnlock) even if an error occurs.
//
// inProgressCompactions is called while DB.mu is held, to get the list of
// in-progress compactions.
func (vs *versionSet) logAndApply(
jobID int,
ve *versionEdit,
metrics map[int]*LevelMetrics,
forceRotation bool,
inProgressCompactions func() []compactionInfo,
) error {
if !vs.writing {
vs.opts.Logger.Fatalf("MANIFEST not locked for writing")
}
defer vs.logUnlock()
if ve.MinUnflushedLogNum != 0 {
if ve.MinUnflushedLogNum < vs.minUnflushedLogNum ||
vs.nextFileNum <= uint64(ve.MinUnflushedLogNum) {
panic(fmt.Sprintf("pebble: inconsistent versionEdit minUnflushedLogNum %d",
ve.MinUnflushedLogNum))
}
}
// This is the next manifest filenum, but if the current file is too big we
// will write this ve to the next file which means what ve encodes is the
// current filenum and not the next one.
//
// TODO(sbhola): figure out why this is correct and update comment.
ve.NextFileNum = vs.nextFileNum
// LastSeqNum is set to the current upper bound on the assigned sequence
// numbers. Note that this is exactly the behavior of RocksDB. LastSeqNum is
// used to initialize versionSet.logSeqNum and versionSet.visibleSeqNum on
// replay. It must be higher than or equal to any than any sequence number
// written to an sstable, including sequence numbers in ingested files.
// Note that LastSeqNum is not (and cannot be) the minimum unflushed sequence
// number. This is fallout from ingestion which allows a sequence number X to
// be assigned to an ingested sstable even though sequence number X-1 resides
// in an unflushed memtable. logSeqNum is the _next_ sequence number that
// will be assigned, so subtract that by 1 to get the upper bound on the
// last assigned sequence number.
logSeqNum := vs.logSeqNum.Load()
ve.LastSeqNum = logSeqNum - 1
if logSeqNum == 0 {
// logSeqNum is initialized to 1 in Open() if there are no previous WAL
// or manifest records, so this case should never happen.
vs.opts.Logger.Fatalf("logSeqNum must be a positive integer: %d", logSeqNum)
}
currentVersion := vs.currentVersion()
fmv := vs.getFormatMajorVersion()
orderingInvariants := fmv.orderingInvariants()
var newVersion *version
// Generate a new manifest if we don't currently have one, or forceRotation
// is true, or the current one is too large.
//
// For largeness, we do not exclusively use MaxManifestFileSize size
// threshold since we have had incidents where due to either large keys or
// large numbers of files, each edit results in a snapshot + write of the
// edit. This slows the system down since each flush or compaction is
// writing a new manifest snapshot. The primary goal of the size-based
// rollover logic is to ensure that when reopening a DB, the number of edits
// that need to be replayed on top of the snapshot is "sane". Rolling over
// to a new manifest after each edit is not relevant to that goal.
//
// Consider the following cases:
// - The number of live files F in the DB is roughly stable: after writing
// the snapshot (with F files), say we require that there be enough edits
// such that the cumulative number of files in those edits, E, be greater
// than F. This will ensure that the total amount of time in logAndApply
// that is spent in snapshot writing is ~50%.
//
// - The number of live files F in the DB is shrinking drastically, say from
// F to F/10: This can happen for various reasons, like wide range
// tombstones, or large numbers of smaller than usual files that are being
// merged together into larger files. And say the new files generated
// during this shrinkage is insignificant compared to F/10, and so for
// this example we will assume it is effectively 0. After this shrinking,
// E = 0.9F, and so if we used the previous snapshot file count, F, as the
// threshold that needs to be exceeded, we will further delay the snapshot
// writing. Which means on DB reopen we will need to replay 0.9F edits to
// get to a version with 0.1F files. It would be better to create a new
// snapshot when E exceeds the number of files in the current version.
//
// - The number of live files F in the DB is growing via perfect ingests
// into L6: Say we wrote the snapshot when there were F files and now we
// have 10F files, so E = 9F. We will further delay writing a new
// snapshot. This case can be critiqued as contrived, but we consider it
// nonetheless.
//
// The logic below uses the min of the last snapshot file count and the file
// count in the current version.
vs.rotationHelper.AddRecord(int64(len(ve.DeletedFiles) + len(ve.NewFiles)))
sizeExceeded := vs.manifest.Size() >= vs.opts.MaxManifestFileSize
requireRotation := forceRotation || vs.manifest == nil
var nextSnapshotFilecount int64
for i := range vs.metrics.Levels {
nextSnapshotFilecount += vs.metrics.Levels[i].NumFiles
}
if sizeExceeded && !requireRotation {
requireRotation = vs.rotationHelper.ShouldRotate(nextSnapshotFilecount)
}
var newManifestFileNum base.DiskFileNum
var prevManifestFileSize uint64
if requireRotation {
newManifestFileNum = vs.getNextDiskFileNum()
prevManifestFileSize = uint64(vs.manifest.Size())
}
// Grab certain values before releasing vs.mu, in case createManifest() needs
// to be called.
minUnflushedLogNum := vs.minUnflushedLogNum
nextFileNum := vs.nextFileNum
var zombies map[base.DiskFileNum]uint64
if err := func() error {
vs.mu.Unlock()
defer vs.mu.Lock()
var err error
if vs.getFormatMajorVersion() < FormatVirtualSSTables && len(ve.CreatedBackingTables) > 0 {
return errors.AssertionFailedf("MANIFEST cannot contain virtual sstable records due to format major version")
}
newVersion, zombies, err = manifest.AccumulateIncompleteAndApplySingleVE(
ve, currentVersion, vs.cmp, vs.opts.Comparer.FormatKey,
vs.opts.FlushSplitBytes, vs.opts.Experimental.ReadCompactionRate,
vs.backingState.fileBackingMap, vs.addFileBacking, vs.removeFileBacking,
orderingInvariants,
)
if err != nil {
return errors.Wrap(err, "MANIFEST apply failed")
}
if newManifestFileNum != 0 {
if err := vs.createManifest(vs.dirname, newManifestFileNum, minUnflushedLogNum, nextFileNum); err != nil {
vs.opts.EventListener.ManifestCreated(ManifestCreateInfo{
JobID: jobID,
Path: base.MakeFilepath(vs.fs, vs.dirname, fileTypeManifest, newManifestFileNum),
FileNum: newManifestFileNum,
Err: err,
})
return errors.Wrap(err, "MANIFEST create failed")
}
}
w, err := vs.manifest.Next()
if err != nil {
return errors.Wrap(err, "MANIFEST next record write failed")
}
// NB: Any error from this point on is considered fatal as we don't know if
// the MANIFEST write occurred or not. Trying to determine that is
// fraught. Instead we rely on the standard recovery mechanism run when a
// database is open. In particular, that mechanism generates a new MANIFEST
// and ensures it is synced.
if err := ve.Encode(w); err != nil {
return errors.Wrap(err, "MANIFEST write failed")
}
if err := vs.manifest.Flush(); err != nil {
return errors.Wrap(err, "MANIFEST flush failed")
}
if err := vs.manifestFile.Sync(); err != nil {
return errors.Wrap(err, "MANIFEST sync failed")
}
if newManifestFileNum != 0 {
// NB: setCurrent is responsible for syncing the data directory.
if err := vs.setCurrent(newManifestFileNum); err != nil {
return errors.Wrap(err, "MANIFEST set current failed")
}
vs.opts.EventListener.ManifestCreated(ManifestCreateInfo{
JobID: jobID,
Path: base.MakeFilepath(vs.fs, vs.dirname, fileTypeManifest, newManifestFileNum),
FileNum: newManifestFileNum,
})
}
return nil
}(); err != nil {
// Any error encountered during any of the operations in the previous
// closure are considered fatal. Treating such errors as fatal is preferred
// to attempting to unwind various file and b-tree reference counts, and
// re-generating L0 sublevel metadata. This may change in the future, if
// certain manifest / WAL operations become retryable. For more context, see
// #1159 and #1792.
vs.opts.Logger.Fatalf("%s", err)
return err
}
if requireRotation {
// Successfully rotated.
vs.rotationHelper.Rotate(nextSnapshotFilecount)
}
// Now that DB.mu is held again, initialize compacting file info in
// L0Sublevels.
inProgress := inProgressCompactions()
newVersion.L0Sublevels.InitCompactingFileInfo(inProgressL0Compactions(inProgress))
// Update the zombie tables set first, as installation of the new version
// will unref the previous version which could result in addObsoleteLocked
// being called.
for fileNum, size := range zombies {
vs.zombieTables[fileNum] = size
}
// Install the new version.
vs.append(newVersion)
if ve.MinUnflushedLogNum != 0 {
vs.minUnflushedLogNum = ve.MinUnflushedLogNum
}
if newManifestFileNum != 0 {
if vs.manifestFileNum != 0 {
vs.obsoleteManifests = append(vs.obsoleteManifests, fileInfo{
fileNum: vs.manifestFileNum,
fileSize: prevManifestFileSize,
})
}
vs.manifestFileNum = newManifestFileNum
}
for level, update := range metrics {
vs.metrics.Levels[level].Add(update)
}
for i := range vs.metrics.Levels {
l := &vs.metrics.Levels[i]
l.NumFiles = int64(newVersion.Levels[i].Len())
l.NumVirtualFiles = newVersion.Levels[i].NumVirtual
l.VirtualSize = newVersion.Levels[i].VirtualSize
l.Size = int64(newVersion.Levels[i].Size())
l.Sublevels = 0
if l.NumFiles > 0 {
l.Sublevels = 1
}
if invariants.Enabled {
levelFiles := newVersion.Levels[i].Slice()
if size := int64(levelFiles.SizeSum()); l.Size != size {
vs.opts.Logger.Fatalf("versionSet metrics L%d Size = %d, actual size = %d", i, l.Size, size)
}
if nVirtual := levelFiles.NumVirtual(); nVirtual != l.NumVirtualFiles {
vs.opts.Logger.Fatalf(
"versionSet metrics L%d NumVirtual = %d, actual NumVirtual = %d",
i, l.NumVirtualFiles, nVirtual,
)
}
if vSize := levelFiles.VirtualSizeSum(); vSize != l.VirtualSize {
vs.opts.Logger.Fatalf(
"versionSet metrics L%d Virtual size = %d, actual size = %d",
i, l.VirtualSize, vSize,
)
}
}
}
vs.metrics.Levels[0].Sublevels = int32(len(newVersion.L0SublevelFiles))
vs.picker = newCompactionPicker(newVersion, vs.opts, inProgress)
if !vs.dynamicBaseLevel {
vs.picker.forceBaseLevel1()
}
return nil
}
func (vs *versionSet) incrementCompactions(
kind compactionKind, extraLevels []*compactionLevel, pickerMetrics compactionPickerMetrics,
) {
switch kind {
case compactionKindDefault:
vs.metrics.Compact.Count++
vs.metrics.Compact.DefaultCount++
case compactionKindFlush, compactionKindIngestedFlushable:
vs.metrics.Flush.Count++
case compactionKindMove:
vs.metrics.Compact.Count++
vs.metrics.Compact.MoveCount++
case compactionKindDeleteOnly:
vs.metrics.Compact.Count++
vs.metrics.Compact.DeleteOnlyCount++
case compactionKindElisionOnly:
vs.metrics.Compact.Count++
vs.metrics.Compact.ElisionOnlyCount++
case compactionKindRead:
vs.metrics.Compact.Count++
vs.metrics.Compact.ReadCount++
case compactionKindRewrite:
vs.metrics.Compact.Count++
vs.metrics.Compact.RewriteCount++
}
if len(extraLevels) > 0 {
vs.metrics.Compact.MultiLevelCount++
}
}
func (vs *versionSet) incrementCompactionBytes(numBytes int64) {
vs.atomicInProgressBytes.Add(numBytes)
}
// createManifest creates a manifest file that contains a snapshot of vs.
func (vs *versionSet) createManifest(
dirname string, fileNum, minUnflushedLogNum base.DiskFileNum, nextFileNum uint64,
) (err error) {
var (
filename = base.MakeFilepath(vs.fs, dirname, fileTypeManifest, fileNum)
manifestFile vfs.File
manifest *record.Writer
)
defer func() {
if manifest != nil {
manifest.Close()
}
if manifestFile != nil {
manifestFile.Close()
}
if err != nil {
vs.fs.Remove(filename)
}
}()
manifestFile, err = vs.fs.Create(filename)
if err != nil {
return err
}
manifest = record.NewWriter(manifestFile)
snapshot := versionEdit{
ComparerName: vs.cmpName,
}
dedup := make(map[base.DiskFileNum]struct{})
for level, levelMetadata := range vs.currentVersion().Levels {
iter := levelMetadata.Iter()
for meta := iter.First(); meta != nil; meta = iter.Next() {
snapshot.NewFiles = append(snapshot.NewFiles, newFileEntry{
Level: level,
Meta: meta,
})
if _, ok := dedup[meta.FileBacking.DiskFileNum]; meta.Virtual && !ok {
dedup[meta.FileBacking.DiskFileNum] = struct{}{}
snapshot.CreatedBackingTables = append(
snapshot.CreatedBackingTables,
meta.FileBacking,
)
}
}
}
// When creating a version snapshot for an existing DB, this snapshot VersionEdit will be
// immediately followed by another VersionEdit (being written in logAndApply()). That
// VersionEdit always contains a LastSeqNum, so we don't need to include that in the snapshot.
// But it does not necessarily include MinUnflushedLogNum, NextFileNum, so we initialize those
// using the corresponding fields in the versionSet (which came from the latest preceding
// VersionEdit that had those fields).
snapshot.MinUnflushedLogNum = minUnflushedLogNum
snapshot.NextFileNum = nextFileNum
w, err1 := manifest.Next()
if err1 != nil {
return err1
}
if err := snapshot.Encode(w); err != nil {
return err
}
if vs.manifest != nil {
vs.manifest.Close()
vs.manifest = nil
}
if vs.manifestFile != nil {
if err := vs.manifestFile.Close(); err != nil {
return err
}
vs.manifestFile = nil
}
vs.manifest, manifest = manifest, nil
vs.manifestFile, manifestFile = manifestFile, nil
return nil
}
func (vs *versionSet) markFileNumUsed(fileNum base.DiskFileNum) {
if vs.nextFileNum <= uint64(fileNum) {
vs.nextFileNum = uint64(fileNum + 1)
}
}
func (vs *versionSet) getNextFileNum() base.FileNum {
x := vs.nextFileNum
vs.nextFileNum++
return base.FileNum(x)
}
func (vs *versionSet) getNextDiskFileNum() base.DiskFileNum {
x := vs.nextFileNum
vs.nextFileNum++
return base.DiskFileNum(x)
}
func (vs *versionSet) append(v *version) {
if v.Refs() != 0 {
panic("pebble: version should be unreferenced")
}
if !vs.versions.Empty() {
vs.versions.Back().UnrefLocked()
}
v.Deleted = vs.obsoleteFn
v.Ref()
vs.versions.PushBack(v)
}
func (vs *versionSet) currentVersion() *version {
return vs.versions.Back()
}
func (vs *versionSet) addLiveFileNums(m map[base.DiskFileNum]struct{}) {
current := vs.currentVersion()
for v := vs.versions.Front(); true; v = v.Next() {
for _, lm := range v.Levels {
iter := lm.Iter()
for f := iter.First(); f != nil; f = iter.Next() {
m[f.FileBacking.DiskFileNum] = struct{}{}
}
}
if v == current {
break
}
}
}
// addObsoleteLocked will add the fileInfo associated with obsolete backing
// sstables to the obsolete tables list.
//
// The file backings in the obsolete list must not appear more than once.
//
// DB.mu must be held when addObsoleteLocked is called.
func (vs *versionSet) addObsoleteLocked(obsolete []*fileBacking) {
if len(obsolete) == 0 {
return
}
obsoleteFileInfo := make([]fileInfo, len(obsolete))
for i, bs := range obsolete {
obsoleteFileInfo[i].fileNum = bs.DiskFileNum
obsoleteFileInfo[i].fileSize = bs.Size
}
if invariants.Enabled {
dedup := make(map[base.DiskFileNum]struct{})
for _, fi := range obsoleteFileInfo {
dedup[fi.fileNum] = struct{}{}
}
if len(dedup) != len(obsoleteFileInfo) {
panic("pebble: duplicate FileBacking present in obsolete list")
}
}
for _, fi := range obsoleteFileInfo {
// Note that the obsolete tables are no longer zombie by the definition of
// zombie, but we leave them in the zombie tables map until they are
// deleted from disk.
if _, ok := vs.zombieTables[fi.fileNum]; !ok {
vs.opts.Logger.Fatalf("MANIFEST obsolete table %s not marked as zombie", fi.fileNum)
}
}
vs.obsoleteTables = append(vs.obsoleteTables, obsoleteFileInfo...)
vs.updateObsoleteTableMetricsLocked()
}
// addObsolete will acquire DB.mu, so DB.mu must not be held when this is
// called.
func (vs *versionSet) addObsolete(obsolete []*fileBacking) {
vs.mu.Lock()
defer vs.mu.Unlock()
vs.addObsoleteLocked(obsolete)
}
func (vs *versionSet) updateObsoleteTableMetricsLocked() {
vs.metrics.Table.ObsoleteCount = int64(len(vs.obsoleteTables))
vs.metrics.Table.ObsoleteSize = 0
for _, fi := range vs.obsoleteTables {
vs.metrics.Table.ObsoleteSize += fi.fileSize
}
}
func setCurrentFunc(
vers FormatMajorVersion, marker *atomicfs.Marker, fs vfs.FS, dirname string, dir vfs.File,
) func(base.DiskFileNum) error {
if vers < formatVersionedManifestMarker {
// Pebble versions before `formatVersionedManifestMarker` used
// the CURRENT file to signal which MANIFEST is current. Ignore
// the filename read during LocateMarker.
return func(manifestFileNum base.DiskFileNum) error {
if err := setCurrentFile(dirname, fs, manifestFileNum); err != nil {
return err
}
if err := dir.Sync(); err != nil {
// This is a panic here, rather than higher in the call
// stack, for parity with the atomicfs.Marker behavior.
// A panic is always necessary because failed Syncs are
// unrecoverable.
panic(errors.Wrap(err, "fatal: MANIFEST dirsync failed"))
}
return nil
}
}
return setCurrentFuncMarker(marker, fs, dirname)
}
func setCurrentFuncMarker(
marker *atomicfs.Marker, fs vfs.FS, dirname string,
) func(base.DiskFileNum) error {
return func(manifestFileNum base.DiskFileNum) error {
return marker.Move(base.MakeFilename(fileTypeManifest, manifestFileNum))
}
}
func findCurrentManifest(
vers FormatMajorVersion, fs vfs.FS, dirname string,
) (marker *atomicfs.Marker, manifestNum base.DiskFileNum, exists bool, err error) {
// NB: We always locate the manifest marker, even if we might not
// actually use it (because we're opening the database at an earlier
// format major version that uses the CURRENT file). Locating a
// marker should succeed even if the marker has never been placed.
var filename string
marker, filename, err = atomicfs.LocateMarker(fs, dirname, manifestMarkerName)
if err != nil {
return nil, base.FileNum(0).DiskFileNum(), false, err
}
if vers < formatVersionedManifestMarker {
// Pebble versions before `formatVersionedManifestMarker` used
// the CURRENT file to signal which MANIFEST is current. Ignore
// the filename read during LocateMarker.
manifestNum, err = readCurrentFile(fs, dirname)
if oserror.IsNotExist(err) {
return marker, base.FileNum(0).DiskFileNum(), false, nil
} else if err != nil {
return marker, base.FileNum(0).DiskFileNum(), false, err
}
return marker, manifestNum, true, nil
}
// The current format major version is >=
// formatVersionedManifestMarker indicating that the
// atomicfs.Marker is the source of truth on the current manifest.
if filename == "" {
// The marker hasn't been set yet. This database doesn't exist.
return marker, base.FileNum(0).DiskFileNum(), false, nil
}
var ok bool
_, manifestNum, ok = base.ParseFilename(fs, filename)
if !ok {
return marker, base.FileNum(0).DiskFileNum(), false, base.CorruptionErrorf("pebble: MANIFEST name %q is malformed", errors.Safe(filename))
}
return marker, manifestNum, true, nil
}
func readCurrentFile(fs vfs.FS, dirname string) (base.DiskFileNum, error) {
// Read the CURRENT file to find the current manifest file.
current, err := fs.Open(base.MakeFilepath(fs, dirname, fileTypeCurrent, base.FileNum(0).DiskFileNum()))
if err != nil {
return base.FileNum(0).DiskFileNum(), errors.Wrapf(err, "pebble: could not open CURRENT file for DB %q", dirname)
}
defer current.Close()
stat, err := current.Stat()
if err != nil {
return base.FileNum(0).DiskFileNum(), err
}
n := stat.Size()
if n == 0 {
return base.FileNum(0).DiskFileNum(), errors.Errorf("pebble: CURRENT file for DB %q is empty", dirname)
}
if n > 4096 {
return base.FileNum(0).DiskFileNum(), errors.Errorf("pebble: CURRENT file for DB %q is too large", dirname)
}
b := make([]byte, n)
_, err = current.ReadAt(b, 0)
if err != nil {
return base.FileNum(0).DiskFileNum(), err
}
if b[n-1] != '\n' {
return base.FileNum(0).DiskFileNum(), base.CorruptionErrorf("pebble: CURRENT file for DB %q is malformed", dirname)
}
b = bytes.TrimSpace(b)
_, manifestFileNum, ok := base.ParseFilename(fs, string(b))
if !ok {
return base.FileNum(0).DiskFileNum(), base.CorruptionErrorf("pebble: MANIFEST name %q is malformed", errors.Safe(b))
}
return manifestFileNum, nil
}
func newFileMetrics(newFiles []manifest.NewFileEntry) map[int]*LevelMetrics {
m := map[int]*LevelMetrics{}
for _, nf := range newFiles {
lm := m[nf.Level]
if lm == nil {
lm = &LevelMetrics{}
m[nf.Level] = lm
}
lm.NumFiles++
lm.Size += int64(nf.Meta.Size)
}
return m
}