RocksDB is a high performance embedded database for key-value data. It is a fork of Google's LevelDB optimized to exploit many CPU cores, and make efficient use of fast storage, such as

solid-state drive A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It i ...

s (SSD), for input/output (I/O) bound workloads. It is based on a log-structured merge-tree (LSM tree) data structure. It is written in C++ and provides official

language binding In programming and software design, binding is an application programming interface (API) that provides glue code specifically made to allow a programming language to use a foreign library or operating system service (one that is not native to ...

s for C++, C, and

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...

; alongside many

third-party language bindings Third party may refer to: Business * Third-party source, a supplier company not owned by the buyer or seller * Third-party beneficiary, a person who could sue on a contract, despite not being an active party * Third-party insurance, such as a Veh ...

. RocksDB is

open-source software Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Ope ...

, and was originally released under a BSD 3-clause license. However, in July 2017 the project was migrated to a dual license of both Apache 2.0 and GPLv2 license, possibly in response to the Apache Software Foundation's blacklist of the previous BSD+Patents license clause. RocksDB is used in production systems at various web-scale enterprises including

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Yahoo! Yahoo! (, styled yahoo''!'' in its logo) is an American web services provider. It is headquartered in Sunnyvale, California and operated by the namesake company Yahoo! Inc. (2017–present), Yahoo Inc., which is 90% owned by investment funds ma ...

, and

LinkedIn LinkedIn () is an American business and employment-oriented online service that operates via websites and mobile apps. Launched on May 5, 2003, the platform is primarily used for professional networking and career development, and allows job s ...

Features

RocksDB, like LevelDB, stores keys and values in arbitrary byte arrays, and data is sorted byte-wise by key or by providing a custom comparator. RocksDB provides all of the features of LevelDB, plus: * Transactions * Backups and

snapshots Snapshot, snapshots or snap shot may refer to: * Snapshot (photography), a photograph taken without preparation Computing * Snapshot (computer storage), the state of a system at a particular point in time * Snapshot (file format) or SNP, a fil ...

Column families {{Short description, A database project that organizes data in packed columns A column family is a database object that contains columns of related data. It is a tuple (pair) that consists of a key–value pair, where the key is mapped to a value ...

Bloom filter A Bloom filter is a space-efficient probabilistic data structure, conceived by Burton Howard Bloom in 1970, that is used to test whether an element is a member of a set. False positive matches are possible, but false negatives are not – in ...

s * Time to live (TTL) support * Universal compaction * Merge operators * Statistics collection * Geospatial indexing and others
List of RocksDB features that are not in LevelDB
RocksDB is not an SQL database (although MyRocks combines RocksDB with

MySQL MySQL () is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A relational database ...

). Like other

NoSQL A NoSQL (originally referring to "non- SQL" or "non-relational") database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases. Such databases have existed ...

and dbm stores, it has no relational data model, and it does not support SQL queries. Also, it has no direct support for secondary indexes, however a user may build their own internally using Column Families or externally. Applications use RocksDB as a library, as it does not provide a server or command-line interface.

History

RocksDB was created at Facebook by Dhruba Borthakur in April 2012, as a fork of LevelDB with the initial stated goal of improving performance for server workloads.

Integration

As an embeddable database, RocksDB can be used as a storage engine within a larger

database In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spa ...

management system (DBMS). For example, CockroachDB uses RocksDB as its storage engine, mostly for transactional workloads while Rocksetbr>uses RocksDB
mostly for analytical data processing. This shows that RocksDB can be used as a storage engine for both

Online transaction processing In online transaction processing (OLTP), information systems typically facilitate and manage transaction-oriented applications. This is contrasted with online analytical processing. The term "transaction" can have two different meanings, both of wh ...

and

Online analytical processing Online analytical processing, or OLAP (), is an approach to answer multi-dimensional analytical (MDA) queries swiftly in computing. OLAP is part of the broader category of business intelligence, which also encompasses relational databases, re ...

Alternative backend

The following projects have been started to replace or offer alternative storage engines for already-established database systems with RocksDB:

ArangoDB

ArangoDB ArangoDB is a free and open-source native graph database system developed by ArangoDB Inc. ArangoDB is a multi-model database system since it supports three data models (graphs, JSON documents, key/value) with one database core and a unified ...

has added RocksDB to its previous storage engine ("mmfiles"). Starting with ArangoDB 3.4, RocksDB will be the default storage engine in ArangoDB.

Cassandra

Cassandra Cassandra or Kassandra (; Ancient Greek: Κασσάνδρα, , also , and sometimes referred to as Alexandra) in Greek mythology was a Trojan priestess dedicated to the god Apollo and fated by him to utter true prophecies but never to be believe ...

on RocksDB can improve the performance of Apache Cassandra significantly (3-4 times faster in general, 100 times faster in some use-cases). The Instagram team at Facebook developed and open-sourced their code, along with benchmarks of their performance results.

MariaDB

MariaDB MariaDB is a community-developed, commercially supported fork of the MySQL relational database management system (RDBMS), intended to remain free and open-source software under the GNU General Public License. Development is led by some of the ...

can use the MyRocks storage engine (which is forked from RocksDB) since MariaDB 10.2.5 (Alpha status) and stable since MariaDB 10.2.16 in 2018.

MongoDB

The MongoRocks project provides a storage module for

MongoDB MongoDB is a source-available cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas. MongoDB is developed by MongoDB Inc. and licensed under the Ser ...

where the storage engine is RocksDB. A related program is Rocks Strata, a tool written in Go, which allows managing incremental backups of MongoDB when RocksDB is used as the storage engine.

MySQL

The MyRocks project creates a new RocksDB-based storage engine for

. In-depth details about MyRocks were presented at Percona Live 2016.

UKV

The UKV project allows users to use RocksDB on par with LevelDB as the underlying Key-Value Store. It represents a shared abstraction for CRUD operations common to every storage engine. It augments it with structured bindings for several high-level languages, like Python,

, and Go.

Embedded

The following database systems and applications have chosen to use RocksDB as their embedded storage engine:

Ceph's BlueStore

The Ceph's BlueStore storage layer uses RocksDB for metadata management in OSD devices.

Apache Flink

Apache Flink uses RocksDB to store checkpoints.

FusionDB

FusionDB uses RocksDB as its storage engine for XML, Key/Value, and JSON.

LogDevice LogsDB

LogDevice's LogsDB is built atop RocksDB.

Manhattan

The Manhattan Distributed Key-Value Store has used RocksDB as its primary engine to store Twitter data since 2018.

Rockset

Th
Rockset
service that is used for operational data analytics uses RocksDB as its storage engine.

SSDB

The ssdb-rocks project uses RocksDB as the storage engine for the SSDB NoSQL Database.

TiDB

The TiDB project uses RocksDB as its storage engine.

YugabyteDB

The YugabyteDB database uses a modified version of RocksDB as part of its DocDB storage engine

Third-party language bindings

Third-party programming language bindings available for RocksDB include: * C * C# * Chicken Scheme * D *

Elixir ELIXIR (the European life-sciences Infrastructure for biological Information) is an initiative that will allow life science laboratories across Europe to share and store their research data as part of an organised network. Its goal is to bring t ...

* Erlang * Go * Haskell *

* Node.js *

Objective-C Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its N ...

, and

Swift Swift or SWIFT most commonly refers to: * SWIFT, an international organization facilitating transactions between banks ** SWIFT code * Swift (programming language) * Swift (bird), a family of birds It may also refer to: Organizations * SWIFT ...

OCaml OCaml ( , formerly Objective Caml) is a general-purpose, multi-paradigm programming language which extends the Caml dialect of ML with object-oriented features. OCaml was created in 1996 by Xavier Leroy, Jérôme Vouillon, Damien Doligez, D ...

Perl Perl is a family of two High-level programming language, high-level, General-purpose programming language, general-purpose, Interpreter (computing), interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it ...

PHP PHP is a General-purpose programming language, general-purpose scripting language geared toward web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1993 and released in 1995. The PHP reference implementati ...

Prolog Prolog is a logic programming language associated with artificial intelligence and computational linguistics. Prolog has its roots in first-order logic, a formal logic, and unlike many other programming languages, Prolog is intended primarily a ...

* Python *

Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapp ...

Rust Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO(OH), ...

References

External links

* {{Facebook navbox NoSQL Database engines Embedded databases C++ libraries Facebook software Key-value databases