Documentation
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Overview ¶
Package offset2 implements a margaret log as persisted sequence of data across multiple files.
Format Defintion ¶
A log consists of three files: data, ofst and jrnl.
* data: a list of length-prefixed data chunks, size is a uint64 (size++[size]byte).
* ofst: a list of uint64, representing entry offsets in 'data'
* jrnl keeps track of the current sequence number, see checkJournal() for more
To read entry 5 in `data`, you follow these steps:
1. Seek to 5*(sizeof(uint64)=8)=40 in `ofset` and read the uint64 representing the offset in `data`
2. Seek to that offset in `data`, read the length-prefix (the uint64 for the size of the entry)
3. Finally, read that amount of data, which is your entry
All uint64's are encoded in BigEndian.
Index ¶
- func LockSink(sink luigi.Sink) luigi.Sink
- type OffsetLog
- func (log *OffsetLog) Append(v interface{}) (int64, error)
- func (log *OffsetLog) Changes() luigi.Observable
- func (log *OffsetLog) CheckConsistency() error
- func (log *OffsetLog) Close() error
- func (log *OffsetLog) FileName() string
- func (log *OffsetLog) Get(seq int64) (interface{}, error)
- func (log *OffsetLog) Null(seq int64) error
- func (log *OffsetLog) Query(specs ...margaret.QuerySpec) (luigi.Source, error)
- func (log *OffsetLog) Replace(seq int64, data []byte) error
- func (log *OffsetLog) Seq() int64
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type OffsetLog ¶ added in v0.4.1
type OffsetLog struct {
// contains filtered or unexported fields
}
func Open ¶
Open returns a the offset log in the directory at `name`. If it is empty or does not exist, a new log will be created.
func (*OffsetLog) Changes ¶ added in v0.4.1
func (log *OffsetLog) Changes() luigi.Observable
func (*OffsetLog) CheckConsistency ¶ added in v0.4.1
CheckConsistency is an fsck for the offset log.
func (*OffsetLog) Null ¶ added in v0.4.1
Null overwrites the entry at seq with zeros updating is kinda odd in append-only but in some cases you still might want to redact entries
Source Files
Directories