README
¶
bitcask
A high performance Key/Value store written in Go with a predictable read/write performance and high throughput. Uses a Bitcask on-disk layout (LSM+WAL) similar to Riak
For a more feature-complete Redis-compatible server, distributed key/value store have a look at Bitraft which uses this library as its backend. Use Bitcask as a starting point or if you want to embed in your application, use Bitraft if you need a complete server/client solution with high availability with a Redis-compatible API.
Features
- Embeddable (
import "github.com/prologic/bitcask") - Builtin CLI (
bitcask) - Builtin Redis-compatible server (
bitcaskd) - Predictable read/write performance
- Low latency
- High throughput (See: Performance )
Development
$ git clone https://github.com/prologic/bitcask.git
$ make
Install
$ go get github.com/prologic/bitcask
Usage (library)
Install the package into your project:
$ go get github.com/prologic/bitcask
package main
import "github.com/prologic/bitcask"
func main() {
db, _ := bitcask.Open("/tmp/db")
defer db.Close()
db.Put([]byte("Hello"), []byte("World"))
val, _ := db.Get([]byte("Hello"))
}
See the godoc for further documentation and other examples.
Usage (tool)
$ bitcask -p /tmp/db set Hello World
$ bitcask -p /tmp/db get Hello
World
Usage (server)
There is also a builtin very simple Redis-compatible server called bitcaskd:
$ ./bitcaskd ./tmp
INFO[0000] starting bitcaskd v0.0.7@146f777 bind=":6379" path=./tmp
Example session:
$ telnet localhost 6379
Trying ::1...
Connected to localhost.
Escape character is '^]'.
SET foo bar
+OK
GET foo
$3
bar
DEL foo
:1
GET foo
$-1
PING
+PONG
QUIT
+OK
Connection closed by foreign host.
Docker
You can also use the Bitcask Docker Image:
$ docker pull prologic/bitcask
$ docker run -d -p 6379:6379 prologic/bitcask
Performance
Benchmarks run on a 11" Macbook with a 1.4Ghz Intel Core i7:
$ make bench
...
goos: darwin
goarch: amd64
pkg: github.com/prologic/bitcask
BenchmarkGet/128B-4 316515 3263 ns/op 39.22 MB/s 160 B/op 1 allocs/op
BenchmarkGet/256B-4 382551 3204 ns/op 79.90 MB/s 288 B/op 1 allocs/op
BenchmarkGet/512B-4 357216 3835 ns/op 133.51 MB/s 576 B/op 1 allocs/op
BenchmarkGet/1K-4 274958 4429 ns/op 231.20 MB/s 1152 B/op 1 allocs/op
BenchmarkGet/2K-4 227764 5013 ns/op 408.55 MB/s 2304 B/op 1 allocs/op
BenchmarkGet/4K-4 187557 5534 ns/op 740.15 MB/s 4864 B/op 1 allocs/op
BenchmarkGet/8K-4 153546 7652 ns/op 1070.56 MB/s 9472 B/op 1 allocs/op
BenchmarkGet/16K-4 115549 10272 ns/op 1594.95 MB/s 18432 B/op 1 allocs/op
BenchmarkGet/32K-4 69592 16405 ns/op 1997.39 MB/s 40960 B/op 1 allocs/op
BenchmarkPut/128BNoSync-4 123519 11094 ns/op 11.54 MB/s 49 B/op 2 allocs/op
BenchmarkPut/256BNoSync-4 84662 13398 ns/op 19.11 MB/s 50 B/op 2 allocs/op
BenchmarkPut/1KNoSync-4 46345 24855 ns/op 41.20 MB/s 58 B/op 2 allocs/op
BenchmarkPut/2KNoSync-4 28820 43817 ns/op 46.74 MB/s 68 B/op 2 allocs/op
BenchmarkPut/4KNoSync-4 13976 90059 ns/op 45.48 MB/s 89 B/op 2 allocs/op
BenchmarkPut/8KNoSync-4 7852 155101 ns/op 52.82 MB/s 130 B/op 2 allocs/op
BenchmarkPut/16KNoSync-4 4848 238113 ns/op 68.81 MB/s 226 B/op 2 allocs/op
BenchmarkPut/32KNoSync-4 2564 391483 ns/op 83.70 MB/s 377 B/op 3 allocs/op
BenchmarkPut/128BSync-4 260 4611273 ns/op 0.03 MB/s 48 B/op 2 allocs/op
BenchmarkPut/256BSync-4 265 4665506 ns/op 0.05 MB/s 48 B/op 2 allocs/op
BenchmarkPut/1KSync-4 256 4757334 ns/op 0.22 MB/s 48 B/op 2 allocs/op
BenchmarkPut/2KSync-4 255 4996788 ns/op 0.41 MB/s 92 B/op 2 allocs/op
BenchmarkPut/4KSync-4 222 5136481 ns/op 0.80 MB/s 98 B/op 2 allocs/op
BenchmarkPut/8KSync-4 223 5530824 ns/op 1.48 MB/s 99 B/op 2 allocs/op
BenchmarkPut/16KSync-4 213 5717880 ns/op 2.87 MB/s 202 B/op 2 allocs/op
BenchmarkPut/32KSync-4 211 5835948 ns/op 5.61 MB/s 355 B/op 3 allocs/op
BenchmarkScan-4 568696 2036 ns/op 392 B/op 33 allocs/op
PASS
For 128B values:
- ~300,000 reads/sec
- ~90,000 writes/sec
- ~490,000 scans/sec
The full benchmark above shows linear performance as you increase key/value sizes.
Stargazers over time
Support
Support the ongoing development of Bitcask!
Sponser
- Become a Sponsor
Contributors
Thank you to all those that have contributed to this project, battle-tested it, used it in their own projects or products, fixed bugs, improved performance and even fix tiny typos in documentation! Thank you and keep contributing!
You can find an AUTHORS file where we keep a list of contributors to the project. If you contriibute a PR please consider adding your name there. There is also Github's own Contributors statistics.
License
bitcask is licensed under the term of the MIT License
Documentation
¶
Overview ¶
Package bitcask implements a high-performance key-value store based on a WAL and LSM.
Example ¶
_, _ = Open("path/to/db")
Output:
Example (WithOptions) ¶
opts := []Option{
WithMaxKeySize(1024),
WithMaxValueSize(4096),
}
_, _ = Open("path/to/db", opts...)
Output:
Index ¶
- Constants
- Variables
- type Bitcask
- func (b *Bitcask) Close() error
- func (b *Bitcask) Delete(key []byte) error
- func (b *Bitcask) Fold(f func(key []byte) error) (err error)
- func (b *Bitcask) Get(key []byte) ([]byte, error)
- func (b *Bitcask) Has(key []byte) bool
- func (b *Bitcask) Keys() chan []byte
- func (b *Bitcask) Len() int
- func (b *Bitcask) Merge() error
- func (b *Bitcask) Put(key, value []byte) error
- func (b *Bitcask) Scan(prefix []byte, f func(key []byte) error) (err error)
- func (b *Bitcask) Stats() (stats Stats, err error)
- func (b *Bitcask) Sync() error
- type Option
- type Stats
Examples ¶
Constants ¶
const ( // DefaultMaxDatafileSize is the default maximum datafile size in bytes DefaultMaxDatafileSize = 1 << 20 // 1MB // DefaultMaxKeySize is the default maximum key size in bytes DefaultMaxKeySize = uint32(64) // 64 bytes // DefaultMaxValueSize is the default value size in bytes DefaultMaxValueSize = uint64(1 << 16) // 65KB // DefaultSync is the default file synchronization action DefaultSync = false )
Variables ¶
var ( // ErrKeyNotFound is the error returned when a key is not found ErrKeyNotFound = errors.New("error: key not found") // ErrKeyTooLarge is the error returned for a key that exceeds the // maximum allowed key size (configured with WithMaxKeySize). ErrKeyTooLarge = errors.New("error: key too large") // ErrValueTooLarge is the error returned for a value that exceeds the // maximum allowed value size (configured with WithMaxValueSize). ErrValueTooLarge = errors.New("error: value too large") // ErrChecksumFailed is the error returned if a key/value retrieved does // not match its CRC checksum ErrChecksumFailed = errors.New("error: checksum failed") // ErrDatabaseLocked is the error returned if the database is locked // (typically opened by another process) ErrDatabaseLocked = errors.New("error: database locked") )
Functions ¶
This section is empty.
Types ¶
type Bitcask ¶
Bitcask is a struct that represents a on-disk LSM and WAL data structure and in-memory hash of key/value pairs as per the Bitcask paper and seen in the Riak database.
func Open ¶
Open opens the database at the given path with optional options. Options can be provided with the `WithXXX` functions that provide configuration options as functions.
func (*Bitcask) Close ¶
Close closes the database and removes the lock. It is important to call Close() as this is the only way to cleanup the lock held by the open database.
func (*Bitcask) Delete ¶
Delete deletes the named key. If the key doesn't exist or an I/O error occurs the error is returned.
func (*Bitcask) Fold ¶
Fold iterates over all keys in the database calling the function `f` for each key. If the function returns an error, no further keys are processed and the error returned.
func (*Bitcask) Get ¶
Get retrieves the value of the given key. If the key is not found or an/I/O error occurs a null byte slice is returned along with the error.
func (*Bitcask) Merge ¶
Merge merges all datafiles in the database. Old keys are squashed and deleted keys removes. Duplicate key/value pairs are also removed. Call this function periodically to reclaim disk space.
func (*Bitcask) Scan ¶
Scan performs a prefix scan of keys matching the given prefix and calling the function `f` with the keys found. If the function returns an error no further keys are processed and the first error returned.
type Option ¶
Option is a function that takes a config struct and modifies it
func WithMaxDatafileSize ¶
WithMaxDatafileSize sets the maximum datafile size option
func WithMaxKeySize ¶
WithMaxKeySize sets the maximum key size option
func WithMaxValueSize ¶
WithMaxValueSize sets the maximum value size option
Source Files
Directories