sequence

Documentation

Overview

Package sequence provides atomic sequence counters for XxSql.

Index

• type Manager
  • func NewManager(path string, walLogger WALLogger) *Manager
  • func (m *Manager) BatchNextValue(name string, count int) ([]int64, error)
  • func (m *Manager) Close() error
  • func (m *Manager) CreateSequence(config SequenceConfig) error
  • func (m *Manager) CurrentValue(name string) (int64, error)
  • func (m *Manager) DropSequence(name string) error
  • func (m *Manager) Exists(name string) bool
  • func (m *Manager) Flush() error
  • func (m *Manager) GetRange(name string, count int) (start, end int64, err error)
  • func (m *Manager) GetSequence(name string) (*Sequence, error)
  • func (m *Manager) ListSequences() []string
  • func (m *Manager) Load() error
  • func (m *Manager) NextValue(name string) (int64, error)
  • func (m *Manager) Persist() error
  • func (m *Manager) Reset(name string) error
  • func (m *Manager) SetCurrentValue(name string, value int64) error
  • func (m *Manager) Stats() Stats
• type Sequence
• type SequenceConfig
  • func DefaultSequenceConfig(name string) SequenceConfig
• type Stats
• type WALLogger

Types

type Manager

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

Manager manages multiple sequences.

func NewManager

func NewManager(path string, walLogger WALLogger) *Manager

NewManager creates a new sequence manager.

func (*Manager) BatchNextValue

func (m *Manager) BatchNextValue(name string, count int) ([]int64, error)

BatchNextValue returns multiple values from a sequence.

func (*Manager) Close

func (m *Manager) Close() error

Close closes the sequence manager.

func (*Manager) CreateSequence

func (m *Manager) CreateSequence(config SequenceConfig) error

CreateSequence creates a new sequence.

func (*Manager) CurrentValue

func (m *Manager) CurrentValue(name string) (int64, error)

CurrentValue returns the current value of a sequence without advancing it.

func (*Manager) DropSequence

func (m *Manager) DropSequence(name string) error

DropSequence drops a sequence.

func (*Manager) Exists

func (m *Manager) Exists(name string) bool

Exists checks if a sequence exists.

func (*Manager) Flush

func (m *Manager) Flush() error

Flush triggers an immediate persist.

func (*Manager) GetRange

func (m *Manager) GetRange(name string, count int) (start, end int64, err error)

GetRange returns a range of values from a sequence. This is more efficient than multiple NextValue calls for bulk operations.

func (*Manager) GetSequence

func (m *Manager) GetSequence(name string) (*Sequence, error)

GetSequence returns information about a sequence.

func (*Manager) ListSequences

func (m *Manager) ListSequences() []string

ListSequences returns a list of all sequence names.

func (*Manager) Load

func (m *Manager) Load() error

Load loads sequences from disk.

func (*Manager) NextValue

func (m *Manager) NextValue(name string) (int64, error)

NextValue returns the next value from a sequence. This is thread-safe and uses atomic operations.

func (*Manager) Persist

func (m *Manager) Persist() error

Persist saves all sequences to disk.

func (*Manager) Reset

func (m *Manager) Reset(name string) error

Reset resets a sequence to its start value.

func (*Manager) SetCurrentValue

func (m *Manager) SetCurrentValue(name string, value int64) error

SetCurrentValue sets the current value of a sequence. This is used for recovery and administrative purposes.

func (*Manager) Stats

func (m *Manager) Stats() Stats

Stats returns statistics about the sequence manager.

type Sequence

type Sequence struct {
	Name        string
	Current     int64
	Increment   int64
	MinValue    int64
	MaxValue    int64
	StartValue  int64
	Cycle       bool
	CacheSize   int32 // Number of values to cache in memory
	CacheEnd    int64 // End of current cache range
	Created     time.Time
	LastUpdated time.Time
}

Sequence represents a named sequence counter.

type SequenceConfig

type SequenceConfig struct {
	Name      string
	Start     int64
	Increment int64
	MinValue  int64
	MaxValue  int64
	Cycle     bool
	CacheSize int32
}

SequenceConfig holds configuration for creating a sequence.

func DefaultSequenceConfig

func DefaultSequenceConfig(name string) SequenceConfig

DefaultSequenceConfig returns default configuration for a sequence.

type Stats

type Stats struct {
	SequenceCount int    `json:"sequence_count"`
	Version       uint64 `json:"version"`
}

Stats holds sequence manager statistics.

type WALLogger

type WALLogger interface {
	LogSequenceCreate(name string, startValue int64) error
	LogSequenceDrop(name string) error
	LogSequenceNext(name string, value int64) error
}

WALLogger defines the interface for WAL logging.