MySQL

MySQL. It is an open-source relational database management system (RDBMS) based on Structured Query Language (SQL). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter, and "SQL". Originally developed and owned by MySQL AB, the company was acquired by Sun Microsystems in 2008, which was subsequently acquired by Oracle Corporation in 2010, making it the current steward.

History

The project was created in 1994 by David Axmark and Michael Widenius in Sweden, with the first internal release occurring in 1995. The founders established the company MySQL AB to oversee its development, which quickly gained traction for its speed and reliability in the burgeoning World Wide Web ecosystem. A pivotal moment came in 2000 when the software adopted the GNU General Public License (GPL), solidifying its open-source status and fostering widespread community adoption. Following its acquisition by Sun Microsystems, the subsequent purchase by Oracle Corporation raised concerns within the open-source software community, leading to notable forks of the codebase.

Features

As a robust RDBMS, it supports ACID (Atomicity, Consistency, Isolation, Durability) compliance through storage engines like InnoDB, ensuring reliable transaction processing. It offers a comprehensive implementation of SQL standards, along with extensions for specific functionalities. Key features include stored procedures and triggers using its own procedural language, support for various character encodings like UTF-8, and multiple storage engines allowing users to choose the optimal one for tasks ranging from high-volume INSERT operations to full-text search. Security is managed through a privilege and account system, with support for Secure Sockets Layer (SSL) connections and integration with Pluggable Authentication Modules (PAM).

Architecture

The system employs a multi-layered architecture, with the core being the SQL parser, query optimizer, and cache layer. A defining characteristic is its storage engine abstraction, where engines like InnoDB and MyISAM handle lower-level tasks of data storage and indexing, allowing the upper SQL layer to remain largely engine-agnostic. The InnoDB engine, the default since version 5.5, provides crucial features such as foreign key constraints, row-level locking, and crash recovery. The server operates using a multi-threaded model, utilizing kernel threads to manage client connections, with replication typically following an asynchronous source-replica model, though semi-synchronous options are available.

Editions and variants

Oracle Corporation offers several official editions, including the freely available MySQL Community Server under the GPL license, and commercial editions like MySQL Enterprise Edition which includes additional tools, support, and management plugins. The acquisition by Oracle directly led to the creation of significant community-driven forks, most notably MariaDB, spearheaded by original co-founder Michael Widenius, and Percona Server, developed by Percona, which focus on retaining open-source development and adding performance enhancements. Cloud-managed services are also prevalent, such as Amazon Relational Database Service (RDS) and Google Cloud SQL.

Use cases and adoption

It serves as the foundational data storage layer for an enormous number of applications, most famously powering the LAMP (software bundle) stack alongside Linux, Apache HTTP Server, and PHP. Major technology companies, including Facebook, Twitter, and YouTube, have historically relied on it for its scalability and performance in web applications. It is extensively used in e-commerce platforms like Magento and WordPress, which itself powers a significant portion of the Internet. Its versatility also extends to embedded database systems, data warehousing, and as a component in larger software suites from companies like SAP SE.

Category:Database management systems Category:Oracle Corporation software