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 Go to latest Published: Jan 2, 2026 License: Apache-2.0 Imports: 17 Imported by: 0

Documentation

Overview

builder.go implements VersionBuilder for applying edits to versions.

VersionBuilder efficiently applies a sequence of edits to a version without creating intermediate versions with full copies of state.

Reference: RocksDB v10.7.5

  • db/version_builder.h
  • db/version_builder.cc

Package version manages database versions and the LSM-tree structure.

A Version represents a snapshot of the database state at a point in time. It contains the list of SST files at each level and provides methods for querying and iterating over the data.

A VersionSet manages all versions and the MANIFEST file. It provides the interface for logging and applying VersionEdits to create new versions.

Reference: RocksDB v10.7.5

  • db/version_set.h (Version class)
  • db/version_set.cc

version_set.go implements the VersionSet which manages all versions.

VersionSet maintains the set of all versions and handles MANIFEST file operations. It provides thread-safe access to the current version.

Reference: RocksDB v10.7.5

  • db/version_set.h (VersionSet class)
  • db/version_set.cc

Whitebox Testing Hooks

This file contains whitebox testing hooks for crash testing (requires -tags crashtest). In production builds, these compile to no-ops with zero overhead. See docs/testing/README.md for usage.

Index

Constants

View Source 
const MaxNumLevels = 7

MaxNumLevels is the maximum number of levels in the LSM-tree.

Variables

View Source 
var (
	ErrNotFound          = errors.New("version: not found")
	ErrCorruption        = errors.New("version: corruption")
	ErrInvalidManifest   = errors.New("version: invalid manifest")
	ErrNoCurrentManifest = errors.New("version: no current manifest")
	ErrManifestTooLarge  = errors.New("version: manifest too large")
)

Errors returned by VersionSet operations.

View Source 
var ErrComparatorMismatch = errors.New("version: comparator mismatch")

ErrComparatorMismatch indicates that the database was created with a different comparator.

Functions

This section is empty.

Types

type Builder 

type Builder struct {
	// contains filtered or unexported fields
}

Builder accumulates changes to a Version and produces a new Version.

Usage: 

builder := NewBuilder(vset, baseVersion)
builder.Apply(edit1)
builder.Apply(edit2)
newVersion := builder.SaveTo(vset)

func NewBuilder 

func NewBuilder(vset *VersionSet, base *Version) *Builder

NewBuilder creates a new Builder based on the given Version.

func (*Builder) Apply 

func (b *Builder) Apply(edit *manifest.VersionEdit) error

Apply applies a VersionEdit to the builder.

func (*Builder) SaveTo 

func (b *Builder) SaveTo(vset *VersionSet) *Version

SaveTo creates a new Version with all the accumulated changes.

type RecoveredColumnFamily 

type RecoveredColumnFamily struct {
	ID   uint32
	Name string
}

RecoveredColumnFamily holds information about a column family recovered from MANIFEST.

type Version 

type Version struct {
	// contains filtered or unexported fields
}

Version represents a snapshot of the database state at a point in time. Each Version keeps track of the set of SST files at each level.

Versions are immutable once created. New versions are created by applying VersionEdits to an existing version via the VersionBuilder.

Versions use reference counting to manage their lifetime. When a Version is no longer needed, call Unref() to decrement the reference count.

func NewVersion 

func NewVersion(vset *VersionSet, versionNumber uint64) *Version

NewVersion creates a new empty Version.

func (*Version) Files 

func (v *Version) Files(level int) []*manifest.FileMetaData

Files returns the files at the given level.

func (*Version) NumFiles 

func (v *Version) NumFiles(level int) int

NumFiles returns the number of files at the given level.

func (*Version) NumLevelBytes 

func (v *Version) NumLevelBytes(level int) uint64

NumLevelBytes returns the total size of files at the given level.

func (*Version) NumLevels 

func (v *Version) NumLevels() int

NumLevels returns the number of levels in use.

func (*Version) OverlappingInputs 

func (v *Version) OverlappingInputs(level int, begin, end []byte) []*manifest.FileMetaData

OverlappingInputs returns the files at the given level that overlap with the key range [begin, end]. If begin or end is nil, it means "no bound".

func (*Version) Ref 

func (v *Version) Ref()

Ref increments the reference count.

func (*Version) TotalFiles 

func (v *Version) TotalFiles() int

TotalFiles returns the total number of files across all levels.

func (*Version) Unref 

func (v *Version) Unref()

Unref decrements the reference count and deletes the version if it reaches 0.

func (*Version) VersionNumber 

func (v *Version) VersionNumber() uint64

VersionNumber returns the version number for debugging.

type VersionSet 

type VersionSet struct {
	// contains filtered or unexported fields
}

VersionSet manages the set of versions and the MANIFEST file.

func NewVersionSet 

func NewVersionSet(opts VersionSetOptions) *VersionSet

NewVersionSet creates a new VersionSet.

func (*VersionSet) Close 

func (vs *VersionSet) Close() error

Close closes the VersionSet and releases resources.

func (*VersionSet) Create 

func (vs *VersionSet) Create() error

Create creates a new database with an initial empty version.

func (*VersionSet) Current 

func (vs *VersionSet) Current() *Version

Current returns the current (newest) version. The caller should call Ref() on the returned version if they need to keep it.

func (*VersionSet) CurrentVersionNumber 

func (vs *VersionSet) CurrentVersionNumber() uint64

CurrentVersionNumber returns the current version number.

func (*VersionSet) GetManifestFileNumber 

func (vs *VersionSet) GetManifestFileNumber() uint64

GetManifestFileNumber returns the current MANIFEST file number.

func (*VersionSet) LastSequence 

func (vs *VersionSet) LastSequence() uint64

LastSequence returns the last sequence number.

func (*VersionSet) LogAndApply 

func (vs *VersionSet) LogAndApply(edit *manifest.VersionEdit) error

LogAndApply logs a VersionEdit to the MANIFEST and applies it.

func (*VersionSet) LogNumber 

func (vs *VersionSet) LogNumber() uint64

LogNumber returns the current log file number.

func (*VersionSet) ManifestFileNumber 

func (vs *VersionSet) ManifestFileNumber() uint64

ManifestFileNumber returns the current manifest file number.

func (*VersionSet) MaxColumnFamily 

func (vs *VersionSet) MaxColumnFamily() uint32

MaxColumnFamily returns the maximum column family ID seen in the MANIFEST.

func (*VersionSet) NextFileNumber 

func (vs *VersionSet) NextFileNumber() uint64

NextFileNumber allocates a new file number.

func (*VersionSet) NextVersionNumber 

func (vs *VersionSet) NextVersionNumber() uint64

NextVersionNumber allocates a new version number.

func (*VersionSet) NumLevelBytes 

func (vs *VersionSet) NumLevelBytes(level int) uint64

NumLevelBytes returns the total size of files at the given level.

func (*VersionSet) NumLevelFiles 

func (vs *VersionSet) NumLevelFiles(level int) int

NumLevelFiles returns the number of files at the given level.

func (*VersionSet) NumLiveVersions 

func (vs *VersionSet) NumLiveVersions() int

NumLiveVersions returns the number of live versions.

func (*VersionSet) Recover 

func (vs *VersionSet) Recover() error

Recover reads the MANIFEST file and recovers the database state.

func (*VersionSet) RecoveredColumnFamilies 

func (vs *VersionSet) RecoveredColumnFamilies() []RecoveredColumnFamily

RecoveredColumnFamilies returns the column families recovered from MANIFEST. This should be called after Recover() to get the non-default CFs.

func (*VersionSet) SetLastSequence 

func (vs *VersionSet) SetLastSequence(seq uint64)

SetLastSequence sets the last sequence number.

func (*VersionSet) SyncManifest 

func (vs *VersionSet) SyncManifest() error

SyncManifest ensures the MANIFEST file is synced to disk. This is useful before creating checkpoints.

type VersionSetOptions 

type VersionSetOptions struct {
	// DBName is the database directory path.
	DBName string

	// FS is the filesystem to use.
	FS vfs.FS

	// MaxManifestFileSize is the maximum size of a MANIFEST file before rotation.
	MaxManifestFileSize uint64

	// NumLevels is the number of levels in the LSM tree.
	NumLevels int

	// ComparatorName is the name of the comparator used by the database.
	// This is validated against the comparator stored in the MANIFEST.
	// If empty, defaults to "leveldb.BytewiseComparator".
	ComparatorName string

	// Logger is an optional logger for MANIFEST operations.
	// If nil, no logging is performed.
	Logger logging.Logger
}

VersionSetOptions configures the VersionSet.

func DefaultVersionSetOptions 

func DefaultVersionSetOptions(dbname string) VersionSetOptions

DefaultVersionSetOptions returns default options.

Source Files

View all Source files

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