Shulou(Shulou.com)06/01 Report--

Mysql engine introduction to Innodb storage engine

Support for transactions, row-level locks and foreign keys in OLTP

Achieve high concurrency through multi-version concurrency control MVCC and achieve four isolation levels of SQL (default repeatable)

Provide insert buffer,double write, adaptive hash index, pre-read

Innodb uses clustered for the storage of data in the table. Each table is stored in the order of primary keys; if the table does not explicitly define a primary key, innodb generates a 6-byte rowid for each row as the primary key.

Myisam storage engine

Does not support transactions, table locks, full-text indexing, fast operation on OLAP

The storage engine consists of MYD and MYI. Myd puts data files and myi puts index files.

Since mysql 5.0, 256T single table data is supported by default.

For myisam storage engine table, mysql database only caches its index files, and the caching of data files is completed by OS itself, which is different from most databases that use LRU algorithm to cache data.

NDB storage engine

All the data is stored in memory, and the lookup speed of the primary key is very fast, which can linearly improve the database performance, high availability, high performance cluster system.

The connection operation of the NDB storage engine is completed in the mysql database layer, not in the storage engine layer, so complex connection operations require huge network overhead.

Memory storage engine

Put the data of the table in memory, and if the database restarts or crashes, the data in the table will be lost. Suitable for temporary data storage temporary table, latitude table in data warehouse, default use hash index, non-B + tree index

Only table locks are supported, but text and blob types are not supported. When storing variable-length field varchar, it follows the fixed-length field char mode, thus wasting space.

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