Documentation
¶
Index ¶
- Constants
- Variables
- type Header
- type Reader
- type Record
- type Scanner
- type Writer
- func (w *Writer) Close() error
- func (w *Writer) Sync() error
- func (w *Writer) WriteKeyValue(key []byte, value []byte) (int64, error)
- func (w *Writer) WriteKeyValueWithTs(key []byte, value []byte, ts time.Time) (int64, error)
- func (w *Writer) WriteTombstone(key []byte) (int64, error)
- func (w *Writer) WriteTombstoneWithTs(key []byte, ts time.Time) (int64, error)
Constants ¶
const (
RecordTypeDelete = 0x44
)
Variables ¶
var ErrCrcChecksumMismatch = errors.New("crc checksum does not match stored value")
var ErrKeyTooLarge = errors.New("key too large")
var ErrValueTooLarge = errors.New("value too large")
Functions ¶
This section is empty.
Types ¶
type Header ¶
type Header struct {
Timestamp time.Time
KeySize uint32
ValueSize uint32
RecordType uint8
ValueType uint8
}
Header contains metadata information about a log record
Timestamp represents the time when the record was created or last modified. KeySize specifies the size in bytes of the record's key. ValueSize specifies the size in bytes of the record's value. RecordType indicates the type of operation (e.g., insert, update, delete). ValueType indicates the data type of the value (e.g., string, integer, blob). Currently it's set to 0x0
type Reader ¶
type Reader struct {
// contains filtered or unexported fields
}
Reader is responsible for reading log records from a file. This implementation uses ReadAt (that uses pread internally on supported files) and hence is safe to access concurrently
func NewReader ¶
NewReader creates a new Record Reader that opens a file at the specified path for reading log records. It starts reading from the 19th byte in the file (To skip the header)
func (*Reader) ReadKeyAt ¶
ReadKeyAt reads a record at the given offset (from the start of the first record). It only reads and populates the key in the returned record. Value is left empty.
func (*Reader) ReadRecordAt ¶
ReadRecordAt reads a record at the given offset (from the start of the first record). It reads both the key and value from the file, and both the Key and Value in the returned record are valid.
func (*Reader) ReadRecordAtStrict ¶
ReadRecordAtStrict reads a record at the given offset (from the start of the first record). It reads both the key and value from the file, and both the Key and Value in the returned record are valid. It also verifies if the record is valid by computing the CRC checksum
type Record ¶
Record represents a single key-value pair in the log file. `Key` and `Value` can be empty depending upon the mode through which the record was read. Size represents the total size of the record (header + key + value + crc), it's useful for determining the start of the next record
type Scanner ¶
type Scanner struct {
// contains filtered or unexported fields
}
Scanner sequentially reads records from the given file. It internally uses a buffered reader to improve performance. This is not meant to be used in Get operation, and is intended to be used for Merge (or other sequential scans of the datafile)
type Writer ¶
type Writer struct {
// contains filtered or unexported fields
}
Writer is responsible for writing log records to the file. There are no locks in this implementation, so it's unsafe to call Writer methods concurrently
func NewBufferedWriter ¶
NewBufferedWriter creates a new Buffered Record Writer that opens a file at the specified path for appending logs Note: It uses a bufio.Writer internally, it's good for merging records, but remember to Sync() otherwise data will get lost
func NewWriter ¶
NewWriter creates a new Record Writer that opens a file at the specified path for appending logs
func (*Writer) Close ¶
Close closes the underlying file, it also writes any pending changes and syncs the changes to the disk
func (*Writer) Sync ¶
Sync flushes any buffered data to the underlying file. It calls sync() on the file
func (*Writer) WriteKeyValue ¶
WriteKeyValue writes the key-value pair as a new log entry to the file. It does not call sync(), so there is a chance that data might get lost if the system crashes. If you need durability, call Sync() after writing. This function returns the offset of the record in the file, measured from the start of the file
func (*Writer) WriteKeyValueWithTs ¶
func (*Writer) WriteTombstone ¶
WriteTombstone writes a tombstone value for the specified key, this function is to be used to delete a key from the store. This function returns the offset of the record in the file, measured from the start of the file
Source Files