Documentation
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Index ¶
- Constants
- type FileFormat
- type FileReader
- func (r *FileReader) Close() error
- func (r *FileReader) IndexHandle() block.Handle
- func (r *FileReader) InitReadHandle(rh *objstorageprovider.PreallocatedReadHandle) objstorage.ReadHandle
- func (r *FileReader) ReadIndexBlock(ctx context.Context, env block.ReadEnv, rh objstorage.ReadHandle) (block.BufferHandle, error)
- func (r *FileReader) ReadValueBlock(ctx context.Context, env block.ReadEnv, rh objstorage.ReadHandle, ...) (block.BufferHandle, error)
- type FileReaderOptions
- type FileWriter
- type FileWriterOptions
- type FileWriterStats
- type Handle
- type HandleSuffix
- type InlineHandle
- type InlineHandlePreface
- type ReaderProvider
- type ReferenceID
- type ValueFetcher
- type ValueReader
Constants ¶
const MaxInlineHandleLength = 4 * binary.MaxVarintLen32
MaxInlineHandleLength is the maximum length of an inline blob handle.
Handle fields are varint encoded, so maximum 5 bytes each.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type FileFormat ¶
type FileFormat uint8
FileFormat identifies the format of a blob file.
const ( // FileFormatV1 is the first version of the blob file format. FileFormatV1 FileFormat = 1 )
func (FileFormat) String ¶
func (f FileFormat) String() string
String implements the fmt.Stringer interface.
type FileReader ¶
type FileReader struct {
// contains filtered or unexported fields
}
FileReader reads a blob file.
func NewFileReader ¶
func NewFileReader( ctx context.Context, r objstorage.Readable, ro FileReaderOptions, ) (*FileReader, error)
NewFileReader opens a blob file for reading.
func (*FileReader) Close ¶
func (r *FileReader) Close() error
Close implements io.Closer, closing the underlying Readable.
func (*FileReader) IndexHandle ¶
func (r *FileReader) IndexHandle() block.Handle
IndexHandle returns the block handle for the file's index block.
func (*FileReader) InitReadHandle ¶
func (r *FileReader) InitReadHandle( rh *objstorageprovider.PreallocatedReadHandle, ) objstorage.ReadHandle
InitReadHandle initializes a read handle for the file reader, using the provided preallocated read handle.
func (*FileReader) ReadIndexBlock ¶
func (r *FileReader) ReadIndexBlock( ctx context.Context, env block.ReadEnv, rh objstorage.ReadHandle, ) (block.BufferHandle, error)
ReadIndexBlock reads the index block from the file.
func (*FileReader) ReadValueBlock ¶
func (r *FileReader) ReadValueBlock( ctx context.Context, env block.ReadEnv, rh objstorage.ReadHandle, h block.Handle, ) (block.BufferHandle, error)
ReadValueBlock reads a value block from the file.
type FileReaderOptions ¶
type FileReaderOptions struct {
block.ReaderOptions
}
FileReaderOptions configures a reader of a blob file.
type FileWriter ¶
type FileWriter struct {
// contains filtered or unexported fields
}
A FileWriter writes a blob file.
func NewFileWriter ¶
func NewFileWriter(fn base.DiskFileNum, w objstorage.Writable, opts FileWriterOptions) *FileWriter
NewFileWriter creates a new FileWriter.
func (*FileWriter) AddValue ¶
func (w *FileWriter) AddValue(v []byte) Handle
AddValue adds the provided value to the blob file, returning a Handle identifying the location of the value.
func (*FileWriter) Close ¶
func (w *FileWriter) Close() (FileWriterStats, error)
Close finishes writing the blob file.
func (*FileWriter) EstimatedSize ¶
func (w *FileWriter) EstimatedSize() uint64
EstimatedSize returns an estimate of the disk space consumed by the blob file if it were closed now.
func (*FileWriter) FlushForTesting ¶
func (w *FileWriter) FlushForTesting()
FlushForTesting flushes the current block to the write queue. Writers should generally not call FlushForTesting, and instead let the heuristics configured through FileWriterOptions handle flushing.
It's exposed so that tests can force flushes to construct blob files with arbitrary structures.
type FileWriterOptions ¶
type FileWriterOptions struct {
Compression block.Compression
ChecksumType block.ChecksumType
FlushGovernor block.FlushGovernor
// Only CPUMeasurer.MeasureCPUBlobFileSecondary is used.
CpuMeasurer base.CPUMeasurer
}
FileWriterOptions are used to configure the FileWriter.
type FileWriterStats ¶
type FileWriterStats struct {
BlockCount uint32
ValueCount uint32
UncompressedValueBytes uint64
FileLen uint64
}
FileWriterStats aggregates statistics about a blob file written by a FileWriter.
func (FileWriterStats) String ¶
func (s FileWriterStats) String() string
String implements the fmt.Stringer interface.
type Handle ¶
type Handle struct {
FileNum base.DiskFileNum
BlockNum uint32
OffsetInBlock uint32
ValueLen uint32
}
Handle describes the location of a value stored within a blob file.
func (Handle) SafeFormat ¶
func (h Handle) SafeFormat(w redact.SafePrinter, _ rune)
SafeFormat implements redact.SafeFormatter.
type HandleSuffix ¶
HandleSuffix is the suffix of an inline handle. It's decoded only when the value is being fetched from the blob file.
func DecodeHandleSuffix ¶
func DecodeHandleSuffix(src []byte) HandleSuffix
DecodeHandleSuffix decodes the block number and offset in block from the encoded handle.
func (HandleSuffix) Encode ¶
func (h HandleSuffix) Encode(b []byte) int
Encode encodes the handle suffix into the provided buffer, returning the number of bytes encoded.
type InlineHandle ¶
type InlineHandle struct {
InlineHandlePreface
HandleSuffix
}
InlineHandle describes a handle as it is encoded within a sstable block. The inline handle does not encode the blob file number outright. Instead it encodes an index into the containing sstable's BlobReferences.
The inline handle is composed of two parts: a preface (InlineHandlePreface) and a suffix (HandleSuffix). The preface is eagerly decoded from the encoded handle when returning an InternalValue to higher layers. The remaining bits (the suffix) are decoded only when the value is being fetched from the blob file.
func (InlineHandle) Encode ¶
func (h InlineHandle) Encode(b []byte) int
Encode encodes the inline handle into the provided buffer, returning the number of bytes encoded.
func (InlineHandle) SafeFormat ¶
func (h InlineHandle) SafeFormat(w redact.SafePrinter, _ rune)
SafeFormat implements redact.SafeFormatter.
func (InlineHandle) String ¶
func (h InlineHandle) String() string
String implements the fmt.Stringer interface.
type InlineHandlePreface ¶
type InlineHandlePreface struct {
ReferenceID ReferenceID
ValueLen uint32
}
InlineHandlePreface is the prefix of an inline handle. It's eagerly decoded when returning an InternalValue to higher layers.
func DecodeInlineHandlePreface ¶
func DecodeInlineHandlePreface(src []byte) (InlineHandlePreface, []byte)
DecodeInlineHandlePreface decodes the blob reference index and value length from the beginning of a variable-width encoded InlineHandle.
type ReaderProvider ¶
type ReaderProvider interface {
// GetValueReader returns a ValueReader for the given file number.
GetValueReader(ctx context.Context, fileNum base.DiskFileNum) (r ValueReader, closeFunc func(), err error)
}
A ReaderProvider is an interface that can be used to retrieve a ValueReader for a given file number.
type ReferenceID ¶
type ReferenceID uint32
ReferenceID identifies a particular blob reference within a table. It's implemented as an index into the slice of the BlobReferences recorded in the manifest.
type ValueFetcher ¶
type ValueFetcher struct {
// contains filtered or unexported fields
}
A ValueFetcher retrieves values stored out-of-band in separate blob files. The ValueFetcher caches accessed file readers to avoid redundant file cache and block cache lookups when performing consecutive value retrievals.
A single ValueFetcher can be used to fetch values from multiple files, and it will internally cache readers for each file.
func (*ValueFetcher) Close ¶
func (r *ValueFetcher) Close() error
Close closes the ValueFetcher and releases all cached readers. Once Close is called, the ValueFetcher is no longer usable.
func (*ValueFetcher) Fetch ¶
func (r *ValueFetcher) Fetch( ctx context.Context, handle []byte, fileNum base.DiskFileNum, valLen uint32, buf []byte, ) (val []byte, callerOwned bool, err error)
Fetch returns the value, given the handle. Fetch must not be called after Close.
func (*ValueFetcher) Init ¶
func (r *ValueFetcher) Init(rp ReaderProvider, env block.ReadEnv)
Init initializes the ValueFetcher.
type ValueReader ¶
type ValueReader interface {
// IndexHandle returns the handle for the file's index block.
IndexHandle() block.Handle
// InitReadHandle initializes a ReadHandle for the file, using the provided
// preallocated read handle to avoid an allocation.
InitReadHandle(rh *objstorageprovider.PreallocatedReadHandle) objstorage.ReadHandle
// ReadValueBlock retrieves a value block described by the provided block
// handle from the block cache, or reads it from the blob file if it's not
// already cached.
ReadValueBlock(context.Context, block.ReadEnv, objstorage.ReadHandle,
block.Handle) (block.BufferHandle, error)
// ReadIndexBlock retrieves the index block from the block cache, or reads
// it from the blob file if it's not already cached.
ReadIndexBlock(context.Context, block.ReadEnv, objstorage.ReadHandle) (block.BufferHandle, error)
}
A ValueReader is an interface defined over a file that can be used to read value blocks.
Source Files