Innobase

Innobase is a storage engine for MySQL, a popular open-source relational database management system. It was originally developed by Innobase Oy, a Finnish company, and was acquired by Oracle Corporation in 2005. Innobase is now the default storage engine for MySQL, known for its robustness and features that are suitable for a wide range of applications, especially those requiring high transaction volumes and data integrity.

A key feature of Innobase is its support for ACID (Atomicity, Consistency, Isolation, Durability) properties. This ensures that database transactions are processed reliably. Atomicity guarantees that a transaction is treated as a single unit of work; it either completes entirely or has no effect. Consistency ensures that a transaction brings the database from one valid state to another. Isolation ensures that concurrent transactions do not interfere with each other. Durability guarantees that once a transaction has been committed, it will remain so even in the event of power loss, crashes, or other system failures.

Innobase utilizes a clustered index, which means that the table data is physically stored in the order of the primary key. This can lead to faster retrieval of data when queries are based on the primary key. It also supports secondary indexes, which are separate data structures that point to the rows in the table. Another significant feature is its support for row-level locking. Unlike table-level locking, row-level locking allows multiple transactions to access and modify different rows within the same table concurrently, significantly improving performance in high-concurrency environments. Innobase also includes features like foreign key constraints for maintaining referential integrity and transactional support for DDL (Data Definition Language) statements, which contributes to its reliability.