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InnoDB
Contact InformationInnoDB
ConfigurationInnoDB
Startup Options and System VariablesInnoDB
TablesInnoDB
Data and Log
FilesInnoDB
DatabaseInnoDB
Database to Another MachineInnoDB
Transaction Model and LockingInnoDB
Multi-VersioningInnoDB
Table and Index StructuresInnoDB
Disk I/O and File Space ManagementInnoDB
Error HandlingInnoDB
Performance Tuning and TroubleshootingInnoDB
Tables
InnoDB
is a transaction-safe (ACID compliant)
storage engine for MySQL that has commit, rollback, and
crash-recovery capabilities to protect user data.
InnoDB
row-level locking (without escalation to
coarser granularity locks) and Oracle-style consistent nonlocking
reads increase multi-user concurrency and performance.
InnoDB
stores user data in clustered indexes to
reduce I/O for common queries based on primary keys. 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.
To determine whether your server supports InnoDB
use the SHOW ENGINES
statement. See
Section 12.4.5.17, “SHOW ENGINES
Syntax”.
Table 13.3. InnoDB
Storage Engine
Features
Storage limits | 64TB | Transactions | Yes | Locking granularity | Row |
MVCC | Yes | Geospatial datatype support | Yes | Geospatial indexing support | No |
B-tree indexes | Yes | Hash indexes | No | Full-text search indexes | No |
Clustered indexes | Yes | Data caches | Yes | Index caches | Yes |
Compressed data | Yes[a] | Encrypted data[b] | Yes | Cluster database support | No |
Replication support[c] | Yes | Foreign key support | Yes | Backup / point-in-time recovery[d] | Yes |
Query cache support | Yes | Update statistics for data dictionary | Yes | ||
[a] Compressed InnoDB tables are supported only by InnoDB Plugin. [b] Implemented in the server (via encryption functions), rather than in the storage engine. [c] Implemented in the server, rather than in the storage product [d] Implemented in the server, rather than in the storage product |
InnoDB
has been designed for maximum performance
when processing large data volumes. Its CPU efficiency is probably
not matched by any other disk-based relational database 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
.
InnoDB
is used in production at numerous large
database sites requiring high performance. The famous Internet news
site Slashdot.org runs on InnoDB
. Mytrix, Inc.
stores more than 1TB of data in InnoDB
, and
another site handles an average load of 800 inserts/updates per
second in InnoDB
.
InnoDB
is published under the same GNU GPL
License Version 2 (of June 1991) as MySQL. For more information on
MySQL licensing, see http://www.mysql.com/company/legal/licensing/.
Additional Resources
A forum dedicated to the InnoDB
storage
engine is available at http://forums.mysql.com/list.php?22.
Innobase Oy also hosts several forums, available at http://forums.innodb.com.
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. As of MySQL 5.4.2, the
InnoDB Plugin
is included in MySQL
5.4 releases. It becomes the built-in version of
InnoDB
in MySQL Server, replacing the version
previously included as the built-in InnoDB
engine. The current version of the InnoDB
Plugin
is 1.0.5 and is considered of Release Candidate
(RC) quality.
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.
For information about these features, see the InnoDB
Plugin
Manual at
http://www.innodb.com/products/innodb_plugin/plugin-documentation.
For general information about using InnoDB
in
MySQL, see Section 13.6, “The InnoDB
Storage Engine”.
For a specific list of changes in MySQL 5.4.2 compared to earlier 5.4.x releases, see Section C.1.2, “Changes in MySQL 5.4.2 (01 September 2009)”.
InnoDB Hot Backup enables you to 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 InnoDB Hot Backup is copying
InnoDB
tables, reads and writes to both
InnoDB
and MyISAM
tables
can continue. During the copying of MyISAM
tables, reads (but not writes) to those tables are permitted. In
addition, InnoDB Hot Backup supports creating
compressed backup files, and performing backups of subsets of
InnoDB
tables. In conjunction with MySQL’s
binary log, users can perform point-in-time recovery.
InnoDB Hot Backup is commercially licensed by
Innobase Oy. For a more complete description of InnoDB
Hot Backup, see
http://www.innodb.com/products/hot-backup/features/
or download the documentation from
http://www.innodb.com/doc/hot_backup/manual.html.
You can order trial, term, and perpetual licenses from Innobase
at
http://www.innodb.com/wp/products/hot-backup/order/.
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