what is innodb in mysql

1 year ago 83

InnoDB is a storage engine for the MySQL database management system that balances high reliability and high performance. It is the default MySQL storage engine since MySQL 5.5.5. Here are some key features of InnoDB:

ACID compliance: InnoDB follows the ACID model, which ensures that transactions have commit, rollback, and crash-recovery capabilities to protect user data.
Row-level locking: InnoDB uses row-level locking, which increases multi-user concurrency and performance.
Clustered index: InnoDB tables have a primary key index called the clustered index, which arranges the data to reduce I/O for primary key queries.
Foreign key support: InnoDB supports foreign key constraints, which allows achieving and maintaining data integrity.
Multiple row formats: InnoDB supports four row formats, each with different storage characteristics: REDUNDANT, COMPACT, DYNAMIC, and COMPRESSED.
Tablespaces: InnoDB tables are created in file-per-table tablespaces by default, but they can also be created in the InnoDB system tablespace or a general tablespace.
Dual licensing: InnoDB is dual licensed under the GNU General Public License and can also be licensed to parties wishing to combine InnoDB in proprietary software.