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14.6.1 Introduction to InnoDB

Key Advantages of InnoDB

InnoDB is a high-reliability and high-performance storage engine for MySQL. Key advantages of InnoDB include:

  • Its design follows the ACID model, with transactions featuring commit, rollback, and crash-recovery capabilities to protect user data.

  • Row-level locking (without escalation to coarser granularity locks) and Oracle-style consistent reads increase multi-user concurrency and performance.

  • InnoDB tables arrange your data on disk to optimize common queries based on primary keys. Each InnoDB table has a primary key index called the clustered index that organizes the data to minimize I/O for primary key lookups.

  • To maintain data integrity, InnoDB also supports FOREIGN KEY referential-integrity constraints.

  • You can freely mix InnoDB tables with tables from other MySQL storage engines, even within the same statement. For example, you can use a join operation to combine data from InnoDB and MEMORY tables in a single query.

  • InnoDB has been designed for CPU efficiency and maximum performance when processing large data volumes.

To determine whether your server supports InnoDB use the SHOW ENGINES statement. See Section, “SHOW ENGINES Syntax”.

Table 14.4 InnoDB Storage Engine Features

Storage limits64TBTransactionsYesLocking granularityRow
MVCCYesGeospatial data type supportYesGeospatial indexing supportYes[a]
B-tree indexesYesT-tree indexesNoHash indexesNo[b]
Full-text search indexesYes[c]Clustered indexesYesData cachesYes
Index cachesYesCompressed dataYes[d]Encrypted data[e]Yes
Cluster database supportNoReplication support[f]YesForeign key supportYes
Backup / point-in-time recovery[g]YesQuery cache supportYesUpdate statistics for data dictionaryYes

[a] InnoDB support for geospatial indexing is available in MySQL 5.7.5 and higher.

[b] InnoDB utilizes hash indexes internally for its Adaptive Hash Index feature.

[c] InnoDB support for FULLTEXT indexes is available in MySQL 5.6.4 and higher.

[d] Compressed InnoDB tables require the InnoDB Barracuda file format.

[e] Implemented in the server (via encryption functions), rather than in the storage engine.

[f] Implemented in the server, rather than in the storage engine.

[g] Implemented in the server, rather than in the storage engine.

The InnoDB storage engine maintains its own buffer pool for caching data and indexes in main memory. InnoDB stores its tables and indexes in a tablespace, which may consist of several files (or raw disk partitions). This is different from, for example, MyISAM tables where each table is stored using separate files. InnoDB tables can be very large even on operating systems where file size is limited to 2GB.

The Windows Essentials installer makes InnoDB the MySQL default storage engine on Windows, if the server being installed supports InnoDB.

To compare the features of InnoDB with other storage engines provided with MySQL, see the Storage Engine Features table in Chapter 14, Storage Engines.

The InnoDB Plugin for MySQL

  • At the 2008 MySQL User Conference, Innobase announced availability of an InnoDB Plugin for MySQL. This plugin for MySQL exploits the pluggable storage engine architecture of MySQL, to permit users to replace the built-in version of InnoDB in MySQL 5.1.

  • As of MySQL 5.1.38, the InnoDB Plugin is included in MySQL 5.1 releases, in addition to the built-in version of InnoDB that has been included in previous releases. MySQL 5.1.42 through 5.1.45 include InnoDB Plugin 1.0.6, which is considered of Release Candidate (RC) quality. MySQL 5.1.46 and up include InnoDB Plugin 1.0.7 or higher, which is considered of General Availability (GA) quality.

  • Prior to MySQL Cluster NDB 7.1.11, MySQL Cluster was not compatible with the InnoDB Plugin.

  • The InnoDB Plugin offers new features, improved performance and scalability, enhanced reliability and new capabilities for flexibility and ease of use. Among the features of the InnoDB Plugin are Fast index creation, table and index compression, file format management, new INFORMATION_SCHEMA tables, capacity tuning, multiple background I/O threads, and group commit.

  • The InnoDB Plugin is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages.

  • For instructions on replacing the built-in version of InnoDB with InnoDB Plugin, see Section, “Using InnoDB Plugin Instead of the Built-In InnoDB”.

MySQL Enterprise Backup and InnoDB

The MySQL Enterprise Backup product lets you back up a running MySQL database, including InnoDB and MyISAM tables, with minimal disruption to operations while producing a consistent snapshot of the database. When MySQL Enterprise Backup is copying InnoDB tables, reads and writes to both InnoDB and MyISAM tables can continue. During the copying of MyISAM and other non-InnoDB tables, reads (but not writes) to those tables are permitted. In addition, MySQL Enterprise Backup can create compressed backup files, and back up subsets of InnoDB tables. In conjunction with the MySQL binary log, you can perform point-in-time recovery. MySQL Enterprise Backup is included as part of the MySQL Enterprise subscription.

For a more complete description of MySQL Enterprise Backup, see Section 23.2, “MySQL Enterprise Backup Overview”.

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