Introduction to Innodb storage engine of Mysql storage engine

In addition to MyISAM, the most widely used in MySQL is Innodb. Innodb is a storage engine developed by a third-party company and adheres to the same open source license agreement as MySQL.

The reason why Innodb is so popular is mainly due to its many features in terms of functions:

1. Support transaction installation

The most important thing about Innodb in terms of functionality is its support for transaction security, which undoubtedly makes Innodb A very important reason why MySQL has become one of the most popular storage engines. And it implements all four levels (READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ and SERIALIZABLE) defined by the SQL92 standard. The support for transaction security has undoubtedly caused many users who had to give up using MySQL due to special business requirements to switch to support
MySQL. Users who previously had a wait-and-see attitude towards database selection have also greatly increased their favorable impression of MySQL.

2. Multi-version data reading

Innodb supports transactions, and in order to ensure the consistency of data and performance during concurrency, it implements multi-version reading of data through undo information.

3. Improvement of locking mechanism

Innodb has changed the locking mechanism of MyISAM and implemented row locking. Although Innodb's row lock mechanism is implemented through indexes, after all, 99% of SQL statements in the database use indexes to retrieve data. Therefore, the row locking mechanism has undoubtedly enhanced Innodb's competitiveness in environments with high concurrency pressure.

4. Implement foreign keys

Innodb implements foreign key references, an important feature of the database, making it possible to control the integrity of some data on the database side. Although many database system tuning experts advise against doing this, adding foreign key control on the database side may still be the lowest-cost option for many users.

In addition to the highlights of the above functions, Innodb also has many other features that often bring users a lot of surprises, and also bring more customers to MySQL. In terms of physical storage, the Innodb storage engine is also different from MyISAM. Although there are also .frm files to store metadata related to table structure definitions, table data and index data are stored together. Whether each table is stored separately or all tables are stored together is completely decided by the user (through specific configuration), and symbolic links are also supported.

The above is the introduction of the Innodb storage engine of Mysql storage engine. For more related content, please pay attention to the PHP Chinese website (www.php.cn)!