SHOW [STORAGE] ENGINES
SHOW ENGINES
displays status
information about the server's storage engines. This is
particularly useful for checking whether a storage engine is
supported, or to see what the default engine is. SHOW
TABLE TYPES
is a synonym, but is deprecated and is
removed in MySQL 5.5.
mysql> SHOW ENGINES\G
*************************** 1. row ***************************
Engine: MyISAM
Support: DEFAULT
Comment: Default engine as of MySQL 3.23 with great performance
*************************** 2. row ***************************
Engine: MEMORY
Support: YES
Comment: Hash based, stored in memory, useful for temporary tables
*************************** 3. row ***************************
Engine: HEAP
Support: YES
Comment: Alias for MEMORY
*************************** 4. row ***************************
Engine: MERGE
Support: YES
Comment: Collection of identical MyISAM tables
*************************** 5. row ***************************
Engine: MRG_MYISAM
Support: YES
Comment: Alias for MERGE
*************************** 6. row ***************************
Engine: ISAM
Support: NO
Comment: Obsolete storage engine, now replaced by MyISAM
*************************** 7. row ***************************
Engine: MRG_ISAM
Support: NO
Comment: Obsolete storage engine, now replaced by MERGE
*************************** 8. row ***************************
Engine: InnoDB
Support: YES
Comment: Supports transactions, row-level locking, and foreign keys
*************************** 9. row ***************************
Engine: INNOBASE
Support: YES
Comment: Alias for INNODB
*************************** 10. row ***************************
Engine: BDB
Support: YES
Comment: Supports transactions and page-level locking
*************************** 11. row ***************************
Engine: BERKELEYDB
Support: YES
Comment: Alias for BDB
*************************** 12. row ***************************
Engine: NDBCLUSTER
Support: NO
Comment: Clustered, fault-tolerant, memory-based tables
*************************** 13. row ***************************
Engine: NDB
Support: NO
Comment: Alias for NDBCLUSTER
*************************** 14. row ***************************
Engine: EXAMPLE
Support: NO
Comment: Example storage engine
*************************** 15. row ***************************
Engine: ARCHIVE
Support: YES
Comment: Archive storage engine
*************************** 16. row ***************************
Engine: CSV
Support: NO
Comment: CSV storage engine
*************************** 17. row ***************************
Engine: FEDERATED
Support: YES
Comment: Federated MySQL storage engine
*************************** 18. row ***************************
Engine: BLACKHOLE
Support: YES
Comment: /dev/null storage engine (anything you write to it disappears)
The output from SHOW ENGINES
may
vary according to the MySQL version used and other factors. The
values shown in the Support
column indicate
the server's level of support for the storage engine, as shown
in the following table.
Value | Meaning |
YES |
The engine is supported and is active |
DEFAULT |
Like YES , plus this is the default engine |
NO |
The engine is not supported |
DISABLED |
The engine is supported but has been disabled |
A value of NO
means that the server was
compiled without support for the engine, so it cannot be
activated at runtime.
A value of DISABLED
occurs either because the
server was started with an option that disables the engine, or
because not all options required to enable it were given. In the
latter case, the error log file should contain a reason
indicating why the option is disabled. See
Section 5.2.1, “The Error Log”.
You might also see DISABLED
for a storage
engine if the server was compiled to support it, but was started
with a
--skip-
option. For example,
engine_name
--skip-innodb
disables the InnoDB
engine. For the
NDBCLUSTER
storage engine,
DISABLED
means the server was compiled with
support for MySQL Cluster, but was not started with the
--ndbcluster
option.
All MySQL servers support MyISAM
tables,
because MyISAM
is the default storage engine.
It is not possible to disable MyISAM
.
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