myis

MyIS is a storage engine developed by MySQL AB (now part of Oracle Corporation) for the MySQL relational database management system. Introduced as the default storage engine in MySQL 5.1, it is designed to provide a balance between performance, reliability, and ease of use for general-purpose database applications.

MyIS is optimized for read-heavy workloads and supports full-text indexing, spatial data, and compression. It uses a table-per-file architecture, where each table is stored as a separate file on disk, simplifying backup and recovery processes. The engine employs a combination of MyISAM (MySQL's original storage engine) and InnoDB (a transactional engine) features, though it is not transactional itself. MyIS is known for its speed in read operations and efficient use of disk space due to its compression capabilities.

Unlike InnoDB, MyIS does not support row-level locking or transactions, which can limit its suitability for applications requiring high concurrency or data integrity guarantees. However, it offers features like table-level locking, which can be advantageous for certain workloads. MyIS also supports multiple storage formats, including dynamic row format (for variable-length columns) and static row format (for fixed-length columns).

While MyIS remains a viable option for specific use cases, its development has been largely stagnant compared to InnoDB, which has become the default storage engine in newer MySQL versions due to its transactional capabilities and ACID compliance. MyIS is still included in MySQL for backward compatibility and applications where its strengths align with performance needs.