Drizzle is a discontinued

free software Free software, libre software, libreware sometimes known as freedom-respecting software is computer software distributed open-source license, under terms that allow users to run the software for any purpose as well as to study, change, distribut ...

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...

relational

database management system In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and an ...

(DBMS) that was forked from the now-defunct 6.0 development branch of the

MySQL MySQL () is an Open-source software, 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 rel ...

DBMS. Like MySQL, Drizzle had a client/server architecture and uses

SQL Structured Query Language (SQL) (pronounced ''S-Q-L''; or alternatively as "sequel") is a domain-specific language used to manage data, especially in a relational database management system (RDBMS). It is particularly useful in handling s ...

as its primary

command language A command language is a language for job control in computing. It is a domain-specific and interpreted language; common examples of a command language are shell or batch programming languages. These languages can be used directly at the ...

. Old Drizzle files are distributed under version 2 and 3 of the

GNU General Public License The GNU General Public Licenses (GNU GPL or simply GPL) are a series of widely used free software licenses, or ''copyleft'' licenses, that guarantee end users the freedom to run, study, share, or modify the software. The GPL was the first ...

(GPL) with portions, including the protocol drivers and replication messaging under the

BSD The Berkeley Software Distribution (BSD), also known as Berkeley Unix or BSD Unix, is a discontinued Unix operating system developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley, beginni ...

license. Early work on the fork was done mid-2008 by Brian Aker. Ongoing development was handled by a team of contributors that included staff members from Canonical Ltd.,

Google Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial ...

Six Apart Six Apart Ltd., sometimes abbreviated 6A, is a software company known for creating the Movable Type blogware, TypePad blog hosting service, and Vox (the blogging platform). The company also is the former owner of LiveJournal. Six Apart is ...

Sun Microsystems Sun Microsystems, Inc., often known as Sun for short, was an American technology company that existed from 1982 to 2010 which developed and sold computers, computer components, software, and information technology services. Sun contributed sig ...

Rackspace Rackspace Technology, Inc. is an American cloud computing company based in San Antonio, Texas. It also has offices in Blacksburg, Virginia, Blacksburg, Virginia and Austin, Texas, as well as in Australia, Canada, United Kingdom, India, Dubai, Sw ...

, Data Differential, Blue Gecko,

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

, Percona,

Hewlett-Packard The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company. It was founded by Bill Hewlett and David Packard in 1939 in a one-car garage in Palo Alto, California ...

Red Hat Red Hat, Inc. (formerly Red Hat Software, Inc.) is an American software company that provides open source software products to enterprises and is a subsidiary of IBM. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North ...

, and others. Drizzle source code, along with instructions on compiling it, are available via the project's Launchpad website. In October 2010, Drizzle had 13,478 total contributions, 96 total contributors, and 37 active contributors. It was also announced that Drizzle had entered Beta. The first GA version was released in March 2011. Drizzle has actively participated in the Google Summer of Code Project since 2010. By late 2013 the project's active phase had come to an end. In July 2016 the maintainers concluded that the time had come for "winding things up officially" because "none of us have any time to dedicate to Drizzle anymore".

Uses

Drizzle is targeted at the web-infrastructure and

cloud computing Cloud computing is "a paradigm for enabling network access to a scalable and elastic pool of shareable physical or virtual resources with self-service provisioning and administration on-demand," according to International Organization for ...

markets. The developers of the product describe it as a "smaller, slimmer and (hopefully) faster version of MySQL".

Platforms and interfaces

Drizzle is written in the C++ programming language, and stores its

string String or strings may refer to: *String (structure), a long flexible structure made from threads twisted together, which is used to tie, bind, or hang other objects Arts, entertainment, and media Films * ''Strings'' (1991 film), a Canadian anim ...

data in the

UTF-8 UTF-8 is a character encoding standard used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode Transformation Format 8-bit''. Almost every webpage is transmitted as UTF-8. UTF-8 supports all 1,112,0 ...

format. It was developed for modern

Unix-like A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

s, including

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

FreeBSD FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable ...

Mac OS X macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

, and

Solaris Solaris is the Latin word for sun. It may refer to: Arts and entertainment Literature, television and film * ''Solaris'' (novel), a 1961 science fiction novel by Stanisław Lem ** ''Solaris'' (1968 film), directed by Boris Nirenburg ** ''Sol ...

– in general, any OS that conforms to

POSIX The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with comm ...

and has a working implementation of the GNU

Autotools The GNU Autotools, also known as the GNU Build System, is a suite of build automation tools designed to support building source code and packaging the resulting binaries. It supports building a codebase for multiple target systems without custom ...

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

was not supported due to its lack of Autotools support.

Features

Drizzle is a re-designed version of the MySQL v6.0 codebase and is designed around a central concept of having a

microkernel In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, ...

architecture. Features such as the query cache and

authentication Authentication (from ''authentikos'', "real, genuine", from αὐθέντης ''authentes'', "author") is the act of proving an Logical assertion, assertion, such as the Digital identity, identity of a computer system user. In contrast with iden ...

system are now plugins to the database, which follow the general theme of "pluggable storage engines" that were introduced in MySQL 5.1. It supports PAM,

LDAP The Lightweight Directory Access Protocol (LDAP ) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed Directory service, directory information services over an Internet Protocol (IP) networ ...

, and HTTP AUTH for authentication via plugins it ships. Via its plugin system it supports logging to files,

syslog In computing, syslog () is a standard for message logging. It allows separation of the software that generates messages, the system that stores them, and the software that reports and analyzes them. Each message is labeled with a facility code, ...

, and remote services such as

RabbitMQ RabbitMQ is an open-source message-broker software (sometimes called message-oriented middleware) that originally implemented the Advanced Message Queuing Protocol (AMQP) and has since been extended with a plug-in architecture to support Str ...

and

Gearman Gearman is an open-source application framework designed to distribute appropriate computer tasks to multiple computers, so large tasks can be done more quickly. In some cases, load balancing rather than raw speed may be the main goal; a Web serv ...

. Drizzle is an

ACID An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

-compliant relational database that supports transactions via an MVCC design.Drizzle Documentation

Microkernel

Plugin points have been added to support replication,

storage engine A database engine (or storage engine) is the underlying software component that a database management system (DBMS) uses to create, read, update and delete (CRUD) data from a database. Most database management systems include their own application ...

s, query rewrite, table functions,

user-defined function A user-defined function (UDF) is a function provided by the user of a program or environment, in a context where the usual assumption is that functions are built into the program or environment. UDFs are usually written for the requirement of its c ...

s, protocol adapters, and multiple query caches.

Indexes

Like MySQL, Drizzle supports concurrent multiple engines. Via this, Drizzle includes built-in support for

B+ tree A B+ tree is an m-ary tree with a variable but often large number of children per node. A B+ tree consists of a root, internal nodes and leaves. The root may be either a leaf or a node with two or more children. A B+ tree can be viewed as a B ...

and

hash Hash, hashes, hash mark, or hashing may refer to: Substances * Hash (food), a coarse mixture of ingredients, often based on minced meat * Hash (stew), a pork and onion-based gravy found in South Carolina * Hash, a nickname for hashish, a canna ...

indexes. Drizzle's query planner is capable of using multiple indexes, from multiple engines to satisfy complex queries, using temporary in-memory

bitmap index A bitmap index is a special kind of database index that uses bitmaps. Bitmap indexes have traditionally been considered to work well for ''low-cardinality columns'', which have a modest number of distinct values, either absolutely, or relative to ...

of operations.

Triggers

Database trigger A database trigger is procedural code that is automatically executed in response to certain Event (computing), events on a particular Table (database), table or View (database), view in a database. The trigger is mostly used for maintaining the Dat ...

s in Drizzle are supported for DML, DDL, and a number of an additional event-based operations in the server. The PrimeBase BLOB streaming system, which allows Drizzle to stream binary large objects (BLOBs) via HTTP, makes use of this system. All triggers for Drizzle currently must be written in C++.

Query rewrite

Any query can be matched and rewritten dynamically that is sent to the server. This action is done before

parsing Parsing, syntax analysis, or syntactic analysis is a process of analyzing a String (computer science), string of Symbol (formal), symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal gramm ...

occurs.

Data types

A wide variety of native

data type In computer science and computer programming, a data type (or simply type) is a collection or grouping of data values, usually specified by a set of possible values, a set of allowed operations on these values, and/or a representation of these ...

s are supported, including: *

Variable-length array In computer programming, a variable-length array (VLA), also called variable-sized or runtime-sized, is an array data structure whose length is determined at runtime, instead of at compile time. In the language C, the VLA is said to have a variab ...

s (including text and composite types) up to 4 GB in total storage size * Arbitrary precision numerics * An

enumerated type In computer programming, an enumerated type (also called enumeration, enum, or factor in the R (programming language), R programming language, a status variable in the JOVIAL programming language, and a categorical variable in statistics) is a data ...

(enum) that supports current 10,000 types

Dynamic SQL

Through support of the EXECUTE command Drizzle can operate dynamic multi-statement SQL. Via the keyword CONCURRENT it can operate these statements in parallel.

Replication

Replication in Drizzle is done by generating "messages" using the Google

Protocol Buffers Protocol Buffers (Protobuf) is a free and open-source cross-platform data format used to serialize structured data. It is useful in developing programs that communicate with each other over a network or for storing data. The method involves an ...

library. These messages are then stored and executed on remote servers. The message format is a non-SQL neutral format which has allowed Drizzle to have replication appliers to RabbitMQ,

Memcached Memcached (pronounced variously /mɛmkæʃˈdiː/ ''mem-cash-dee'' or /ˈmɛmkæʃt/ ''mem-cashed'') is a general-purpose distributed memory-caching system. It is often used to speed up dynamic database-driven websites by caching data and object ...

, MySQL,

Voldemort Lord Voldemort ( , in the films) is a fictional character and the main antagonist in the ''Harry Potter'' series of novels by J. K. Rowling. He first appears in '' Harry Potter and the Philosopher's Stone'' (1997) and returns either in pe ...

, and

Apache Cassandra Apache Cassandra is a free and open-source software, free and open-source database management system designed to handle large volumes of data across multiple Commodity computing, commodity servers. The system prioritizes availability and scalab ...

Support and licensing

Drizzle is licensed under version two and three of the GPL, with some parts, such as libdrizzle client library, under the

license.

References

External links

* The official website was live until 2016, http://www.drizzle.org
Waybackmachine's copy

FLOSS interview with Brian on the future direction of Drizzle
* {{Software in the Public Interest MySQL Free database management systems Software forks Relational database management software for Linux Client-server database management systems