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dgraph-io / badger

Fast key-value DB in Go.
https://dgraph.io/badger
Apache License 2.0
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database document-database go golang key-value library ssd

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BadgerDB

Go Reference Go Report Card Sourcegraph ci-badger-tests ci-badger-bank-tests ci-golang-lint

Badger mascot

BadgerDB is an embeddable, persistent and fast key-value (KV) database written in pure Go. It is the underlying database for Dgraph, a fast, distributed graph database. It's meant to be a performant alternative to non-Go-based key-value stores like RocksDB.

Project Status

Badger is stable and is being used to serve data sets worth hundreds of terabytes. Badger supports concurrent ACID transactions with serializable snapshot isolation (SSI) guarantees. A Jepsen-style bank test runs nightly for 8h, with --race flag and ensures the maintenance of transactional guarantees. Badger has also been tested to work with filesystem level anomalies, to ensure persistence and consistency. Badger is being used by a number of projects which includes Dgraph, Jaeger Tracing, UsenetExpress, and many more.

The list of projects using Badger can be found here.

Badger v1.0 was released in Nov 2017, and the latest version that is data-compatible with v1.0 is v1.6.0.

Badger v2.0 was released in Nov 2019 with a new storage format which won't be compatible with all of the v1.x. Badger v2.0 supports compression, encryption and uses a cache to speed up lookup.

Badger v3.0 was released in January 2021. This release improves compaction performance.

Please consult the Changelog for more detailed information on releases.

For more details on our version naming schema please read Choosing a version.

Table of Contents

Getting Started

Installing

To start using Badger, install Go 1.19 or above. Badger v3 and above needs go modules. From your project, run the following command

$ go get github.com/dgraph-io/badger/v4

This will retrieve the library.

Installing Badger Command Line Tool

Badger provides a CLI tool which can perform certain operations like offline backup/restore. To install the Badger CLI, retrieve the repository and checkout the desired version. Then run

$ cd badger
$ go install .

This will install the badger command line utility into your $GOBIN path.

Choosing a version

BadgerDB is a pretty special package from the point of view that the most important change we can make to it is not on its API but rather on how data is stored on disk.

This is why we follow a version naming schema that differs from Semantic Versioning.

Following these rules:

For a longer explanation on the reasons behind using a new versioning naming schema, you can read VERSIONING.

Badger Documentation

Badger Documentation is available at https://dgraph.io/docs/badger

Resources

Blog Posts

  1. Introducing Badger: A fast key-value store written natively in Go
  2. Make Badger crash resilient with ALICE
  3. Badger vs LMDB vs BoltDB: Benchmarking key-value databases in Go
  4. Concurrent ACID Transactions in Badger

Design

Badger was written with these design goals in mind:

Badger’s design is based on a paper titled WiscKey: Separating Keys from Values in SSD-conscious Storage.

Comparisons

Feature Badger RocksDB BoltDB
Design LSM tree with value log LSM tree only B+ tree
High Read throughput Yes No Yes
High Write throughput Yes Yes No
Designed for SSDs Yes (with latest research 1) Not specifically 2 No
Embeddable Yes Yes Yes
Sorted KV access Yes Yes Yes
Pure Go (no Cgo) Yes No Yes
Transactions Yes, ACID, concurrent with SSI3 Yes (but non-ACID) Yes, ACID
Snapshots Yes Yes Yes
TTL support Yes Yes No
3D access (key-value-version) Yes4 No No

1 The WISCKEY paper (on which Badger is based) saw big wins with separating values from keys, significantly reducing the write amplification compared to a typical LSM tree.

2 RocksDB is an SSD optimized version of LevelDB, which was designed specifically for rotating disks. As such RocksDB's design isn't aimed at SSDs.

3 SSI: Serializable Snapshot Isolation. For more details, see the blog post Concurrent ACID Transactions in Badger

4 Badger provides direct access to value versions via its Iterator API. Users can also specify how many versions to keep per key via Options.

Benchmarks

We have run comprehensive benchmarks against RocksDB, Bolt and LMDB. The benchmarking code, and the detailed logs for the benchmarks can be found in the badger-bench repo. More explanation, including graphs can be found the blog posts (linked above).

Projects Using Badger

Below is a list of known projects that use Badger:

If you are using Badger in a project please send a pull request to add it to the list.

Contributing

If you're interested in contributing to Badger see CONTRIBUTING.

Contact