y

Documentation

Index

• Variables
• func AssertTrue(b bool)
• func AssertTruef(b bool, format string, args ...interface{})
• func Check(err error)
• func Check2(_ interface{}, err error)
• func CompareKeys(key1 []byte, key2 []byte) int
• func Copy(a []byte) []byte
• func CreateSyncedFile(filename string, sync bool) (*os.File, error)
• func KeyWithTs(key []byte, ts uint64) []byte
• func Madvise(b []byte, readahead bool) error
• func Mmap(fd *os.File, writable bool, size int64) ([]byte, error)
• func Munmap(b []byte) error
• func OpenExistingSyncedFile(filename string, sync bool) (*os.File, error)
• func OpenSyncedFile(filename string, sync bool) (*os.File, error)
• func OpenTruncFile(filename string, sync bool) (*os.File, error)
• func ParseKey(key []byte) []byte
• func ParseTs(key []byte) uint64
• func Safecopy(a []byte, src []byte) []byte
• func SameKey(src, dst []byte) bool
• func Wrap(err error) error
• func Wrapf(err error, format string, args ...interface{}) error
• type Closer
  • func NewCloser(initial int) *Closer
  • func (lc *Closer) AddRunning(delta int)
  • func (lc *Closer) Done()
  • func (lc *Closer) HasBeenClosed() <-chan struct{}
  • func (lc *Closer) Signal()
  • func (lc *Closer) SignalAndWait()
  • func (lc *Closer) Wait()
• type Iterator
• type MergeIterator
  • func NewMergeIterator(iters []Iterator, reversed bool) *MergeIterator
  • func (s *MergeIterator) Close() error
  • func (s *MergeIterator) Key() []byte
  • func (s *MergeIterator) Next()
  • func (s *MergeIterator) Rewind()
  • func (s *MergeIterator) Seek(key []byte)
  • func (s *MergeIterator) Valid() bool
  • func (s *MergeIterator) Value() ValueStruct
• type Slice
  • func (s *Slice) Resize(sz int) []byte
• type ValueStruct
  • func (v *ValueStruct) Decode(b []byte)
  • func (v *ValueStruct) Encode(b []byte)
  • func (v *ValueStruct) EncodedSize() uint16

Variables

var (
	// LSMSize has size of the LSM in bytes
	LSMSize *expvar.Map
	// VlogSize has size of the value log in bytes
	VlogSize *expvar.Map
	// PendingWrites tracks the number of pending writes.
	PendingWrites *expvar.Map

	// NumReads has cumulative number of reads
	NumReads *expvar.Int
	// NumWrites has cumulative number of writes
	NumWrites *expvar.Int
	// NumBytesRead has cumulative number of bytes read
	NumBytesRead *expvar.Int
	// NumBytesWritten has cumulative number of bytes written
	NumBytesWritten *expvar.Int
	// NumLSMGets is number of LMS gets
	NumLSMGets *expvar.Map
	// NumLSMBloomHits is number of LMS bloom hits
	NumLSMBloomHits *expvar.Map
	// NumGets is number of gets
	NumGets *expvar.Int
	// NumPuts is number of puts
	NumPuts *expvar.Int
	// NumBlockedPuts is number of blocked puts
	NumBlockedPuts *expvar.Int
	// NumMemtableGets is number of memtable gets
	NumMemtableGets *expvar.Int
)

var (

	// CastagnoliCrcTable is a CRC32 polynomial table
	CastagnoliCrcTable = crc32.MakeTable(crc32.Castagnoli)
)

var ErrEOF = errors.New("End of mapped region")

ErrEOF indicates an end of file when trying to read from a memory mapped file and encountering the end of slice.

Functions

func AssertTrue

func AssertTrue(b bool)

AssertTrue asserts that b is true. Otherwise, it would log fatal.

func AssertTruef

func AssertTruef(b bool, format string, args ...interface{})

AssertTruef is AssertTrue with extra info.

func Check

func Check(err error)

Check logs fatal if err != nil.

func Check2

func Check2(_ interface{}, err error)

Check2 acts as convenience wrapper around Check, using the 2nd argument as error.

func CompareKeys

func CompareKeys(key1 []byte, key2 []byte) int

CompareKeys checks the key without timestamp and checks the timestamp if keyNoTs is same. a<timestamp> would be sorted higher than aa<timestamp> if we use bytes.compare All keys should have timestamp.

func Copy

func Copy(a []byte) []byte

Copy copies a byte slice and returns the copied slice.

func CreateSyncedFile

func CreateSyncedFile(filename string, sync bool) (*os.File, error)

CreateSyncedFile creates a new file (using O_EXCL), errors if it already existed.

func KeyWithTs

func KeyWithTs(key []byte, ts uint64) []byte

KeyWithTs generates a new key by appending ts to key.

func Madvise

func Madvise(b []byte, readahead bool) error

Madvise uses the madvise system call to give advise about the use of memory when using a slice that is memory-mapped to a file. Set the readahead flag to false if page references are expected in random order.

func Mmap

func Mmap(fd *os.File, writable bool, size int64) ([]byte, error)

Mmap uses the mmap system call to memory-map a file. If writable is true, memory protection of the pages is set so that they may be written to as well.

func Munmap

func Munmap(b []byte) error

Munmap unmaps a previously mapped slice.

func OpenExistingSyncedFile

func OpenExistingSyncedFile(filename string, sync bool) (*os.File, error)

OpenExistingSyncedFile opens an existing file, errors if it doesn't exist.

func OpenSyncedFile

func OpenSyncedFile(filename string, sync bool) (*os.File, error)

OpenSyncedFile creates the file if one doesn't exist.

func OpenTruncFile

func OpenTruncFile(filename string, sync bool) (*os.File, error)

OpenTruncFile opens the file with O_RDWR | O_CREATE | O_TRUNC

func ParseKey

func ParseKey(key []byte) []byte

ParseKey parses the actual key from the key bytes.

func ParseTs

func ParseTs(key []byte) uint64

ParseTs parses the timestamp from the key bytes.

func Safecopy

func Safecopy(a []byte, src []byte) []byte

Safecopy does append(a[:0], src...).

func SameKey

func SameKey(src, dst []byte) bool

SameKey checks for key equality ignoring the version timestamp suffix.

func Wrap

func Wrap(err error) error

Wrap wraps errors from external lib.

func Wrapf

func Wrapf(err error, format string, args ...interface{}) error

Wrapf is Wrap with extra info.

Types

type Closer

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

Closer holds the two things we need to close a goroutine and wait for it to finish: a chan to tell the goroutine to shut down, and a WaitGroup with which to wait for it to finish shutting down.

func NewCloser

func NewCloser(initial int) *Closer

NewCloser constructs a new Closer, with an initial count on the WaitGroup.

func (*Closer) AddRunning

func (lc *Closer) AddRunning(delta int)

AddRunning Add()'s delta to the WaitGroup.

func (*Closer) Done

func (lc *Closer) Done()

Done calls Done() on the WaitGroup.

func (*Closer) HasBeenClosed

func (lc *Closer) HasBeenClosed() <-chan struct{}

HasBeenClosed gets signaled when Signal() is called.

func (*Closer) Signal

func (lc *Closer) Signal()

Signal signals the HasBeenClosed signal.

func (*Closer) SignalAndWait

func (lc *Closer) SignalAndWait()

SignalAndWait calls Signal(), then Wait().

func (*Closer) Wait

func (lc *Closer) Wait()

Wait waits on the WaitGroup. (It waits for NewCloser's initial value, AddRunning, and Done calls to balance out.)

type Iterator

type Iterator interface {
	Next()
	Rewind()
	Seek(key []byte)
	Key() []byte
	Value() ValueStruct
	Valid() bool

	// All iterators should be closed so that file garbage collection works.
	Close() error
}

Iterator is an interface for a basic iterator.

type MergeIterator

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

MergeIterator merges multiple iterators. NOTE: MergeIterator owns the array of iterators and is responsible for closing them.

func NewMergeIterator

func NewMergeIterator(iters []Iterator, reversed bool) *MergeIterator

NewMergeIterator returns a new MergeIterator from a list of Iterators.

func (*MergeIterator) Close

func (s *MergeIterator) Close() error

Close implements y.Iterator

func (*MergeIterator) Key

func (s *MergeIterator) Key() []byte

Key returns the key associated with the current iterator

func (*MergeIterator) Next

func (s *MergeIterator) Next()

Next returns the next element. If it is the same as the current key, ignore it.

func (*MergeIterator) Rewind

func (s *MergeIterator) Rewind()

Rewind seeks to first element (or last element for reverse iterator).

func (*MergeIterator) Seek

func (s *MergeIterator) Seek(key []byte)

Seek brings us to element with key >= given key.

func (*MergeIterator) Valid

func (s *MergeIterator) Valid() bool

Valid returns whether the MergeIterator is at a valid element.

func (*MergeIterator) Value

func (s *MergeIterator) Value() ValueStruct

Value returns the value associated with the iterator.

type Slice

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

Slice holds a reusable buf, will reallocate if you request a larger size than ever before. One problem is with n distinct sizes in random order it'll reallocate log(n) times.

func (*Slice) Resize

func (s *Slice) Resize(sz int) []byte

Resize reuses the Slice's buffer (or makes a new one) and returns a slice in that buffer of length sz.

type ValueStruct

type ValueStruct struct {
	Meta     byte
	UserMeta byte
	Value    []byte

	Version uint64 // This field is not serialized. Only for internal usage.
}

ValueStruct represents the value info that can be associated with a key, but also the internal Meta field.

func (*ValueStruct) Decode

func (v *ValueStruct) Decode(b []byte)

Decode uses the length of the slice to infer the length of the Value field.

func (*ValueStruct) Encode

func (v *ValueStruct) Encode(b []byte)

Encode expects a slice of length at least v.EncodedSize(). TODO: Who calls this?

func (*ValueStruct) EncodedSize

func (v *ValueStruct) EncodedSize() uint16

EncodedSize is the size of the ValueStruct when encoded