chunkenc

Documentation

Index

• Constants
• func IsOutOfOrderChunk(e Encoding) bool
• func IsValidEncoding(e Encoding) bool
• type Appender
• type Chunk
  • func FromData(e Encoding, d []byte) (Chunk, error)
• type Encoding
  • func (e Encoding) String() string
• type Iterator
  • func MockSeriesIterator(timestamps []int64, values []float64) Iterator
  • func NewNopIterator() Iterator
• type OOOXORChunk
  • func (c *OOOXORChunk) Encoding() Encoding
• type Pool
  • func NewPool() Pool
• type XORChunk
  • func NewXORChunk() *XORChunk
  • func (c *XORChunk) Appender() (Appender, error)
  • func (c *XORChunk) Bytes() []byte
  • func (c *XORChunk) Compact()
  • func (c *XORChunk) Encoding() Encoding
  • func (c *XORChunk) Iterator(it Iterator) Iterator
  • func (c *XORChunk) NumSamples() int

Constants

const (
	OutOfOrderMask = 0b10000000
	EncOOOXOR      = EncXOR | OutOfOrderMask
)

Chunk encodings for out-of-order chunks. These encodings must be only used by the Head block for its internal bookkeeping.

Functions

func IsOutOfOrderChunk

func IsOutOfOrderChunk(e Encoding) bool

func IsValidEncoding

func IsValidEncoding(e Encoding) bool

Types

type Appender

type Appender interface {
	Append(int64, float64)
}

Appender adds sample pairs to a chunk.

type Chunk

type Chunk interface {
	// Bytes returns the underlying byte slice of the chunk.
	Bytes() []byte

	// Encoding returns the encoding type of the chunk.
	Encoding() Encoding

	// Appender returns an appender to append samples to the chunk.
	Appender() (Appender, error)

	// The iterator passed as argument is for re-use.
	// Depending on implementation, the iterator can
	// be re-used or a new iterator can be allocated.
	Iterator(Iterator) Iterator

	// NumSamples returns the number of samples in the chunk.
	NumSamples() int

	// Compact is called whenever a chunk is expected to be complete (no more
	// samples appended) and the underlying implementation can eventually
	// optimize the chunk.
	// There's no strong guarantee that no samples will be appended once
	// Compact() is called. Implementing this function is optional.
	Compact()
}

Chunk holds a sequence of sample pairs that can be iterated over and appended to.

func FromData

func FromData(e Encoding, d []byte) (Chunk, error)

FromData returns a chunk from a byte slice of chunk data. This is there so that users of the library can easily create chunks from bytes.

type Encoding

type Encoding uint8

Encoding is the identifier for a chunk encoding.

const (
	EncNone Encoding = iota
	EncXOR
)

The different available chunk encodings.

func (Encoding) String

func (e Encoding) String() string

type Iterator

type Iterator interface {
	// Next advances the iterator by one.
	Next() bool
	// Seek advances the iterator forward to the first sample with the timestamp equal or greater than t.
	// If current sample found by previous `Next` or `Seek` operation already has this property, Seek has no effect.
	// Seek returns true, if such sample exists, false otherwise.
	// Iterator is exhausted when the Seek returns false.
	Seek(t int64) bool
	// At returns the current timestamp/value pair.
	// Before the iterator has advanced At behaviour is unspecified.
	At() (int64, float64)
	// Err returns the current error. It should be used only after iterator is
	// exhausted, that is `Next` or `Seek` returns false.
	Err() error
}

Iterator is a simple iterator that can only get the next value. Iterator iterates over the samples of a time series, in timestamp-increasing order.

func MockSeriesIterator

func MockSeriesIterator(timestamps []int64, values []float64) Iterator

MockSeriesIterator returns an iterator for a mock series with custom timeStamps and values.

func NewNopIterator

func NewNopIterator() Iterator

NewNopIterator returns a new chunk iterator that does not hold any data.

type OOOXORChunk

type OOOXORChunk struct {
	*XORChunk
}

OOOXORChunk holds a XORChunk and overrides the Encoding() method.

func (*OOOXORChunk) Encoding

func (c *OOOXORChunk) Encoding() Encoding

type Pool

type Pool interface {
	Put(Chunk) error
	Get(e Encoding, b []byte) (Chunk, error)
}

Pool is used to create and reuse chunk references to avoid allocations.

func NewPool

func NewPool() Pool

NewPool returns a new pool.

type XORChunk

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

XORChunk holds XOR encoded sample data.

func NewXORChunk

func NewXORChunk() *XORChunk

NewXORChunk returns a new chunk with XOR encoding of the given size.

func (*XORChunk) Appender

func (c *XORChunk) Appender() (Appender, error)

Appender implements the Chunk interface. It is not valid to call Appender() multiple times concurrently or to use multiple Appenders on the same chunk.

func (*XORChunk) Bytes

func (c *XORChunk) Bytes() []byte

Bytes returns the underlying byte slice of the chunk.

func (*XORChunk) Compact

func (c *XORChunk) Compact()

func (*XORChunk) Encoding

func (c *XORChunk) Encoding() Encoding

Encoding returns the encoding type.

func (*XORChunk) Iterator

func (c *XORChunk) Iterator(it Iterator) Iterator

Iterator implements the Chunk interface. Iterator() must not be called concurrently with any modifications to the chunk, but after it returns you can use an Iterator concurrently with an Appender or other Iterators.

func (*XORChunk) NumSamples

func (c *XORChunk) NumSamples() int

NumSamples returns the number of samples in the chunk.