package y

import "github.com/dgraph-io/badger/v2/y"

Index

Constants 

const (
	// Sync indicates that O_DSYNC should be set on the underlying file,
	// ensuring that data writes do not return until the data is flushed
	// to disk.
	Sync = 1 << iota
	// ReadOnly opens the underlying file on a read-only basis.
	ReadOnly
)

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 ErrChecksumMismatch = errors.New("checksum mismatch")

ErrChecksumMismatch is returned at checksum mismatch. 

var (
	// ErrEOF indicates an end of file when trying to read from a memory mapped file
	// and encountering the end of slice.
	ErrEOF = errors.New("End of mapped region")
)
var (
	NoEventLog trace.EventLog = nilEventLog{}
)

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 BytesToU32 

func BytesToU32(b []byte) uint32

BytesToU32 converts the given byte slice to uint32

func BytesToU32Slice 

func BytesToU32Slice(b []byte) []uint32

BytesToU32Slice converts the given byte slice to uint32 slice

func CalculateChecksum 

func CalculateChecksum(data []byte, ct pb.Checksum_Algorithm) uint64

CalculateChecksum calculates checksum for data using ct checksum type.

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, 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 FixedDuration 

func FixedDuration(d time.Duration) string

FixedDuration returns a string representation of the given duration with the hours, minutes, and seconds.

func GenerateIV 

func GenerateIV() ([]byte, error)

GenerateIV generates IV.

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 OpenExistingFile 

func OpenExistingFile(filename string, flags uint32) (*os.File, error)

OpenExistingFile 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, 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 U32SliceToBytes 

func U32SliceToBytes(u32s []uint32) []byte

U32SliceToBytes converts the given Uint32 slice to byte slice

func U32ToBytes 

func U32ToBytes(v uint32) []byte

U32ToBytes converts the given Uint32 to bytes

func VerifyChecksum 

func VerifyChecksum(data []byte, expected *pb.Checksum) error

VerifyChecksum validates the checksum for the data against the given expected checksum.

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.

func XORBlock 

func XORBlock(src, key, iv []byte) ([]byte, error)

XORBlock encrypts the given data with AES and XOR's with IV. Can be used for both encryption and decryption. IV is of AES block size.

func ZSTDCompress 

func ZSTDCompress(dst, src []byte, compressionLevel int) ([]byte, error)

ZSTDCompress compresses a block using ZSTD algorithm.

func ZSTDCompressBound 

func ZSTDCompressBound(srcSize int) int

ZSTDCompressBound returns the worst case size needed for a destination buffer. Klauspost ZSTD library does not provide any API for Compression Bound. This calculation is based on the DataDog ZSTD library. See https://pkg.go.dev/github.com/DataDog/zstd#CompressBound

func ZSTDDecompress 

func ZSTDDecompress(dst, src []byte) ([]byte, error)

ZSTDDecompress decompresses a block using ZSTD algorithm.

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 PageBuffer 

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

PageBuffer consists of many pages. A page is a wrapper over []byte. PageBuffer can act as a replacement of bytes.Buffer. Instead of having single underlying buffer, it has multiple underlying buffers. Hence it avoids any copy during relocation(as happens in bytes.Buffer). PageBuffer allocates memory in pages. Once a page is full, it will allocate page with double the size of previous page. Its function are not thread safe.

func NewPageBuffer 

func NewPageBuffer(pageSize int) *PageBuffer

NewPageBuffer returns a new PageBuffer with first page having size pageSize.

func (*PageBuffer) Bytes 

func (b *PageBuffer) Bytes() []byte

Bytes returns whole Buffer data as single []byte.

func (*PageBuffer) Len 

func (b *PageBuffer) Len() int

Len returns length of PageBuffer.

func (*PageBuffer) NewReaderAt 

func (b *PageBuffer) NewReaderAt(offset int) *PageBufferReader

NewReaderAt returns a reader which starts reading from offset in page buffer.

func (*PageBuffer) Truncate 

func (b *PageBuffer) Truncate(n int)

Truncate truncates PageBuffer to length n.

func (*PageBuffer) Write 

func (b *PageBuffer) Write(data []byte) (int, error)

Write writes data to PageBuffer b. It returns number of bytes written and any error encountered.

func (*PageBuffer) WriteByte 

func (b *PageBuffer) WriteByte(data byte) error

WriteByte writes data byte to PageBuffer and returns any encountered error.

func (*PageBuffer) WriteTo 

func (b *PageBuffer) WriteTo(w io.Writer) (int64, error)

WriteTo writes whole buffer to w. It returns number of bytes written and any error encountered.

type PageBufferReader 

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

PageBufferReader is a reader for PageBuffer.

func (*PageBufferReader) Read 

func (r *PageBufferReader) Read(p []byte) (int, error)

Read reads upto len(p) bytes. It returns number of bytes read and any error encountered.

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 Throttle 

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

Throttle allows a limited number of workers to run at a time. It also provides a mechanism to check for errors encountered by workers and wait for them to finish.

func NewThrottle 

func NewThrottle(max int) *Throttle

NewThrottle creates a new throttle with a max number of workers.

func (*Throttle) Do 

func (t *Throttle) Do() error

Do should be called by workers before they start working. It blocks if there are already maximum number of workers working. If it detects an error from previously Done workers, it would return it.

func (*Throttle) Done 

func (t *Throttle) Done(err error)

Done should be called by workers when they finish working. They can also pass the error status of work done.

func (*Throttle) Finish 

func (t *Throttle) Finish() error

Finish waits until all workers have finished working. It would return any error passed by Done. If Finish is called multiple time, it will wait for workers to finish only once(first time). From next calls, it will return same error as found on first call.

type ValueStruct 

type ValueStruct struct {
	Meta      byte
	UserMeta  byte
	ExpiresAt uint64
	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().

func (*ValueStruct) EncodeTo 

func (v *ValueStruct) EncodeTo(buf *bytes.Buffer)

EncodeTo should be kept in sync with the Encode function above. The reason this function exists is to avoid creating byte arrays per key-value pair in table/builder.go.

func (*ValueStruct) EncodedSize 

func (v *ValueStruct) EncodedSize() uint32

EncodedSize is the size of the ValueStruct when encoded

type WaterMark 

type WaterMark struct {
	Name string
	// contains filtered or unexported fields
}

WaterMark is used to keep track of the minimum un-finished index. Typically, an index k becomes finished or "done" according to a WaterMark once Done(k) has been called

  1. as many times as Begin(k) has, AND
  2. a positive number of times.

An index may also become "done" by calling SetDoneUntil at a time such that it is not inter-mingled with Begin/Done calls.

Since doneUntil and lastIndex addresses are passed to sync/atomic packages, we ensure that they are 64-bit aligned by putting them at the beginning of the structure.

func (*WaterMark) Begin 

func (w *WaterMark) Begin(index uint64)

Begin sets the last index to the given value.

func (*WaterMark) BeginMany 

func (w *WaterMark) BeginMany(indices []uint64)

BeginMany works like Begin but accepts multiple indices.

func (*WaterMark) Done 

func (w *WaterMark) Done(index uint64)

Done sets a single index as done.

func (*WaterMark) DoneMany 

func (w *WaterMark) DoneMany(indices []uint64)

DoneMany works like Done but accepts multiple indices.

func (*WaterMark) DoneUntil 

func (w *WaterMark) DoneUntil() uint64

DoneUntil returns the maximum index that has the property that all indices less than or equal to it are done.

func (*WaterMark) Init 

func (w *WaterMark) Init(closer *Closer)

Init initializes a WaterMark struct. MUST be called before using it.

func (*WaterMark) LastIndex 

func (w *WaterMark) LastIndex() uint64

LastIndex returns the last index for which Begin has been called.

func (*WaterMark) SetDoneUntil 

func (w *WaterMark) SetDoneUntil(val uint64)

SetDoneUntil sets the maximum index that has the property that all indices less than or equal to it are done.

func (*WaterMark) WaitForMark 

func (w *WaterMark) WaitForMark(ctx context.Context, index uint64) error

WaitForMark waits until the given index is marked as done.

Source Files

checksum.go encrypt.go error.go event_log.go file_dsync.go iterator.go metrics.go mmap.go mmap_unix.go watermark.go y.go zstd.go

Version
v2.2007.4 (latest)
Published
Aug 25, 2021
Platform
linux/amd64
Imports
25 packages
Last checked
1 week ago –

Tools for package owners.