SHOW [STORAGE] ENGINES
显示引擎
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.
For information about MySQL storage engines, seeChapter 15,The InnoDB Storage Engine, andChapter 16,Alternative Storage Engines.
mysql> SHOW ENGINES\G *************************** 1. row *************************** Engine: ARCHIVE Support: YES Comment: Archive storage engine Transactions: NO XA: NO Savepoints: NO *************************** 2. row *************************** Engine: BLACKHOLE Support: YES Comment: /dev/null storage engine (anything you write to it disappears) Transactions: NO XA: NO Savepoints: NO *************************** 3. row *************************** Engine: MRG_MYISAM Support: YES Comment: Collection of identical MyISAM tables Transactions: NO XA: NO Savepoints: NO *************************** 4. row *************************** Engine: FEDERATED Support: NO Comment: Federated MySQL storage engine Transactions: NULL XA: NULL Savepoints: NULL *************************** 5. row *************************** Engine: MyISAM Support: YES Comment: MyISAM storage engine Transactions: NO XA: NO Savepoints: NO *************************** 6. row *************************** Engine: PERFORMANCE_SCHEMA Support: YES Comment: Performance Schema Transactions: NO XA: NO Savepoints: NO *************************** 7. row *************************** Engine: InnoDB Support: DEFAULT Comment: Supports transactions, row-level locking, and foreign keys Transactions: YES XA: YES Savepoints: YES *************************** 8. row *************************** Engine: MEMORY Support: YES Comment: Hash based, stored in memory, useful for temporary tables Transactions: NO XA: NO Savepoints: NO *************************** 9. row *************************** Engine: CSV Support: YES Comment: CSV storage engine Transactions: NO XA: NO Savepoints: NO
The output from显示引擎
may vary according to the MySQL version used and other factors.
显示引擎
output has these columns:
Engine
The name of the storage engine.
Support
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 engineNO
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 enabled 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 should contain a reason indicating why the option is disabled. SeeSection 5.4.2, “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 theengine_name
NDB
storage engine,DISABLED
means the server was compiled with support for NDB Cluster, but was not started with the--ndbcluster
option.All MySQL servers support
MyISAM
tables. It is not possible to disableMyISAM
.Comment
A brief description of the storage engine.
Transactions
Whether the storage engine supports transactions.
XA
Whether the storage engine supports XA transactions.
保存点s
Whether the storage engine supports savepoints.
Storage engine information is also available from theINFORMATION_SCHEMA
ENGINES
table. SeeSection 26.3.13, “The INFORMATION_SCHEMA ENGINES Table”.