y

Documentation

Index

• Constants
• Variables
• func AssertTrue(b bool)
• func AssertTruef(b bool, format string, args ...interface{})
• func Check(err error)
• func Check2(_ interface{}, err error)
• func CreateSyncedFile(filename string, sync bool) (*os.File, error)
• 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 Safecopy(a []byte, src []byte) []byte
• func ValueStructSerializedSize(size uint16) int
• 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 MakeValueStruct(value []byte, meta byte, userMeta byte, casCounter uint64) ValueStruct
  • func (v *ValueStruct) DecodeEntireSlice(b []byte)
  • func (v *ValueStruct) Encode(b []byte)
  • func (v *ValueStruct) EncodedSize() int

Constants

const (
	MetaSize     = 1
	UserMetaSize = 1
	CasSize      = 8
)

Constants used in serialization sizes, and in ValueStruct serialization

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 CreateSyncedFile

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

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

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 Safecopy

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

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

func ValueStructSerializedSize

func ValueStructSerializedSize(size uint16) int

ValueStructSerializedSize converts a value size to the full serialized size of value + metadata.

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 {
	Value      []byte
	Meta       byte
	UserMeta   byte
	CASCounter uint64
}

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

func MakeValueStruct

func MakeValueStruct(value []byte, meta byte, userMeta byte, casCounter uint64) ValueStruct

MakeValueStruct is the most convenient way for unit tests to make a ValueStruct. (Also, the code will break if we add another field.)

func (*ValueStruct) DecodeEntireSlice

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

DecodeEntireSlice 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().

func (*ValueStruct) EncodedSize

func (v *ValueStruct) EncodedSize() int

EncodedSize is the size of the ValueStruct when encoded