bbolt
====
[![Go Report Card](https://goreportcard.com/badge/github.com/coreos/bbolt?style=flat-square)](https://goreportcard.com/report/github.com/coreos/bbolt)
[![Coverage](https://codecov.io/gh/coreos/bbolt/branch/master/graph/badge.svg)](https://codecov.io/gh/coreos/bbolt)
[![Godoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](https://godoc.org/github.com/coreos/bbolt)
bbolt is a fork of [Ben Johnson's][gh_ben] [Bolt][bolt] key/value
store. The purpose of this fork is to provide the Go community with an active
maintenance and development target for Bolt; the goal is improved reliability
and stability. bbolt includes bug fixes, performance enhancements, and features
not found in Bolt while preserving backwards compatibility with the Bolt API.
Bolt is a pure Go key/value store inspired by [Howard Chu's][hyc_symas]
[LMDB project][lmdb]. The goal of the project is to provide a simple,
fast, and reliable database for projects that don't require a full database
server such as Postgres or MySQL.
Since Bolt is meant to be used as such a low-level piece of functionality,
simplicity is key. The API will be small and only focus on getting values
and setting values. That's it.
[gh_ben]: https://github.com/benbjohnson
[bolt]: https://github.com/boltdb/bolt
[hyc_symas]: https://twitter.com/hyc_symas
[lmdb]: http://symas.com/mdb/
## Project Status
Bolt is stable, the API is fixed, and the file format is fixed. Full unit
test coverage and randomized black box testing are used to ensure database
consistency and thread safety. Bolt is currently used in high-load production
environments serving databases as large as 1TB. Many companies such as
Shopify and Heroku use Bolt-backed services every day.
## Table of Contents
- [Getting Started](#getting-started)
- [Installing](#installing)
- [Opening a database](#opening-a-database)
- [Transactions](#transactions)
- [Read-write transactions](#read-write-transactions)
- [Read-only transactions](#read-only-transactions)
- [Batch read-write transactions](#batch-read-write-transactions)
- [Managing transactions manually](#managing-transactions-manually)
- [Using buckets](#using-buckets)
- [Using key/value pairs](#using-keyvalue-pairs)
- [Autoincrementing integer for the bucket](#autoincrementing-integer-for-the-bucket)
- [Iterating over keys](#iterating-over-keys)
- [Prefix scans](#prefix-scans)
- [Range scans](#range-scans)
- [ForEach()](#foreach)
- [Nested buckets](#nested-buckets)
- [Database backups](#database-backups)
- [Statistics](#statistics)
- [Read-Only Mode](#read-only-mode)
- [Mobile Use (iOS/Android)](#mobile-use-iosandroid)
- [Resources](#resources)
- [Comparison with other databases](#comparison-with-other-databases)
- [Postgres, MySQL, & other relational databases](#postgres-mysql--other-relational-databases)
- [LevelDB, RocksDB](#leveldb-rocksdb)
- [LMDB](#lmdb)
- [Caveats & Limitations](#caveats--limitations)
- [Reading the Source](#reading-the-source)
- [Other Projects Using Bolt](#other-projects-using-bolt)
## Getting Started
### Installing
To start using Bolt, install Go and run `go get`:
```sh
$ go get github.com/coreos/bbolt/...
```
This will retrieve the library and install the `bolt` command line utility into
your `$GOBIN` path.
### Opening a database
The top-level object in Bolt is a `DB`. It is represented as a single file on
your disk and represents a consistent snapshot of your data.
To open your database, simply use the `bolt.Open()` function:
```go
package main
import (
"log"
bolt "github.com/coreos/bbolt"
)
func main() {
// Open the my.db data file in your current directory.
// It will be created if it doesn't exist.
db, err := bolt.Open("my.db", 0600, nil)
if err != nil {
log.Fatal(err)
}
defer db.Close()
...
}
```
Please note that Bolt obtains a file lock on the data file so multiple processes
cannot open the same database at the same time. Opening an already open Bolt
database will cause it to hang until the other process closes it. To prevent
an indefinite wait you can pass a timeout option to the `Open()` function:
```go
db, err := bolt.Open("my.db", 0600, &bolt.Options{Timeout: 1 * time.Second})
```
### Transactions
Bolt allows only one read-write transaction at a time but allows as many
read-only transactions as you want at a time. Each transaction has a consistent
view of the data as it existed when the transaction started.
Individual transactions and all objects created from them (e.g. buckets, keys)
are not thread safe. To work with data in multiple goroutines you must start
a transaction for each one or use locking to ensure only one goroutine accesses
a transaction at a time. Creating transaction from the `DB` is thread safe.
Read-only transactions and read-write transactions should not depend on one
another and generally shouldn't be opened simultaneously in the same goroutine.
This can cause a deadlock as the read-write transaction needs to periodically
re-map the data file but it cannot do so while a read-only transaction is open.
#### Read-write transactions
To start a read-write transaction, you can use the `DB.Update()` function:
```go
err := db.Update(func(tx *bolt.Tx) error {
...
return nil
})
```
Inside the closure, you have a consistent view of the database. You commit the
transaction by returning `nil` at the end. You can also rollback the transaction
at any point by returning an error. All database operations are allowed inside
a read-write transaction.
Always check the return error as it will report any disk failures that can cause
your transaction to not complete. If you return an error within your closure
it will be passed through.
#### Read-only transactions
To start a read-only transaction, you can use the `DB.View()` function:
```go
err := db.View(func(tx *bolt.Tx) error {
...
return nil
})
```
You also get a consistent view of the database within this closure, however,
no mutating operations are allowed within a read-only transaction. You can only
retrieve buckets, retrieve values, and copy the database within a read-only
transaction.
#### Batch read-write transactions
Each `DB.Update()` waits for disk to commit the writes. This overhead
can be minimized by combining multiple updates with the `DB.Batch()`
function:
```go
err := db.Batch(func(tx *bolt.Tx) error {
...
return nil
})
```
Concurrent Batch calls are opportunistically combined into larger
transactions. Batch is only useful when there are multiple goroutines
calling it.
The trade-off is that `Batch` can call the given
function multiple times, if parts of the transaction fail. The
function must be idempotent and side effects must take effect only
after a successful return from `DB.Batch()`.
For example: don't display messages from inside the function, instead
set variables in the enclosing scope:
```go
var id uint64
err := db.Batch(func(tx *bolt.Tx) error {
// Find last key in bucket, decode as bigendian uint64, increment
// by one, encode back to []byte, and add new key.
...
id = newValue
return nil
})
if err != nil {
return ...
}
fmt.Println("Allocated ID %d", id)
```
#### Managing transactions manually
The `DB.View()` and `DB.Update()` functions are wrappers around the `DB.Begin()`
function. These helper functions will start the transaction, execute a function,
and then safely close your transaction if an error is returned. This is the
recommended way to use Bolt transactions.
However, sometimes you may want to manually start and end your transactions.
You can use the `DB.Begin()` function directly but **please** be sure to close
the transaction.
```go
// Start a writable transaction.
tx, err := db.Begin(true)
if err != nil {
return err
}
defer tx.Rollback()
// Use the transaction...
_, err := tx.CreateBucket([]byte("MyBucket"))
if err != nil {
return err
}
// Commit the transaction and check for error.
if err := tx.Commit(); err !
没有合适的资源?快使用搜索试试~ 我知道了~
bilib1.zip(国内某知名视频网站前端源代码,go语言后端开发,工程文件)
共2000个文件
go:17746个
build:3828个
md:1446个
需积分: 9 7 下载量 124 浏览量
2019-06-26
21:15:19
上传
评论 1
收藏 46.95MB ZIP 举报
温馨提示
国内某知名视频网站前端源代码,go语言后端开发,工程文件
资源推荐
资源详情
资源评论
收起资源包目录
bilib1.zip(国内某知名视频网站前端源代码,go语言后端开发,工程文件) (2000个子文件)
gccgo_c.c 1KB
generated.pb.go 1.22MB
tables.go 858KB
tables.go 801KB
tables.go 799KB
pinyin_dict.go 788KB
tables.go 666KB
zstdlib.go 601KB
tables.go 489KB
api.pb.go 478KB
storage-gen.go 396KB
api.pb.go 365KB
api.pb.go 358KB
AppIndex.pb.go 339KB
tables.go 338KB
api.pb.go 311KB
api.pb.go 305KB
service.pb.go 282KB
api.pb.go 267KB
types.go 264KB
tables.go 263KB
api.pb.go 258KB
index.pb.go 244KB
api.pb.go 239KB
api.pb.go 234KB
api.pb.go 231KB
api.pb.go 225KB
capsule.pb.go 224KB
api.pb.go 222KB
end2end_test.go 215KB
generated.pb.go 193KB
test.pb.go 184KB
item.pb.go 174KB
types_swagger_doc_generated.go 173KB
api.pb.go 173KB
guard.pb.go 173KB
model.pb.go 172KB
api.pb.go 168KB
icon_test.go 167KB
api.pb.go 166KB
tables.go 164KB
wallet.pb.go 164KB
resource.pb.go 161KB
data_codec.go 155KB
zz_generated.deepcopy.go 154KB
api.pb.go 153KB
api.pb.go 152KB
api.pb.go 151KB
Record.pb.go 149KB
order.pb.go 144KB
Room.pb.go 143KB
Room.pb.go 143KB
data_ffjson.go 142KB
tables.go 141KB
api.pb.go 141KB
proto.pb.go 140KB
promotion.pb.go 139KB
api.pb.go 137KB
api.pb.go 133KB
model.pb.go 129KB
titans.pb.go 128KB
channelz.pb.go 127KB
api.pb.go 124KB
api.pb.go 120KB
model.pb.go 119KB
PayLive.pb.go 119KB
api.pb.go 118KB
api.pb.go 118KB
zerrors_linux_ppc64le.go 116KB
zerrors_linux_ppc64.go 116KB
zerrors_linux_s390x.go 116KB
zone.go 116KB
descriptor.pb.go 115KB
descriptor.pb.go 114KB
Master.pb.go 114KB
zerrors_linux_mips64le.go 114KB
zerrors_linux_mipsle.go 114KB
zerrors_linux_mips64.go 114KB
zerrors_linux_mips.go 114KB
zerrors_linux_arm.go 114KB
zerrors_linux_amd64.go 113KB
zerrors_linux_386.go 113KB
zerrors_linux_arm64.go 113KB
generator.go 112KB
AnchorReward.pb.go 112KB
strip.go 111KB
service.pb.go 111KB
tables.go 109KB
Room.pb.go 108KB
api.pb.go 108KB
gift.pb.go 108KB
api.pb.go 107KB
api.pb.go 104KB
errname.go 104KB
PayGoods.pb.go 101KB
user_resource.pb.go 101KB
entity.go 98KB
api.pb.go 97KB
RoomMng.pb.go 97KB
cityhash_test.go 95KB
共 2000 条
- 1
- 2
- 3
- 4
- 5
- 6
- 20
资源评论
马心宇
- 粉丝: 7
- 资源: 17
上传资源 快速赚钱
- 我的内容管理 展开
- 我的资源 快来上传第一个资源
- 我的收益 登录查看自己的收益
- 我的积分 登录查看自己的积分
- 我的C币 登录后查看C币余额
- 我的收藏
- 我的下载
- 下载帮助
安全验证
文档复制为VIP权益,开通VIP直接复制
信息提交成功