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15.7.7.18 SHOW ENGINES Statement

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.

For information about MySQL storage engines, seeChapter 17,The InnoDB Storage Engine, andChapter 18,Alternative Storage Engines.

mysql> SHOW ENGINES\G*************************** 1. row ***************************      Engine: MEMORY     Support: YES     Comment: Hash based, stored in memory, useful for temporary tablesTransactions: NO          XA: NO  Savepoints: NO*************************** 2. row ***************************      Engine: InnoDB     Support: DEFAULT     Comment: Supports transactions, row-level locking, and foreign keysTransactions: YES          XA: YES  Savepoints: YES*************************** 3. row ***************************      Engine: PERFORMANCE_SCHEMA     Support: YES     Comment: Performance SchemaTransactions: NO          XA: NO  Savepoints: NO*************************** 4. row ***************************      Engine: MyISAM     Support: YES     Comment: MyISAM storage engineTransactions: NO          XA: NO  Savepoints: NO*************************** 5. row ***************************      Engine: MRG_MYISAM     Support: YES     Comment: Collection of identical MyISAM tablesTransactions: NO          XA: NO  Savepoints: NO*************************** 6. row ***************************      Engine: BLACKHOLE     Support: YES     Comment: /dev/null storage engine (anything you write to it disappears)Transactions: NO          XA: NO  Savepoints: NO*************************** 7. row ***************************      Engine: CSV     Support: YES     Comment: CSV storage engineTransactions: NO          XA: NO  Savepoints: NO*************************** 8. row ***************************      Engine: ARCHIVE     Support: YES     Comment: Archive storage engineTransactions: NO          XA: NO  Savepoints: NO

The output fromSHOW ENGINES may vary according to the MySQL version used and other factors.

SHOW ENGINES 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.

    ValueMeaning
    YESThe engine is supported and is active
    DEFAULTLikeYES, plus this is the default engine
    NOThe engine is not supported
    DISABLEDThe engine is supported but has been disabled

    A value ofNO means that the server was compiled without support for the engine, so it cannot be enabled at runtime.

    A value ofDISABLED 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 7.4.2, “The Error Log”.

    You might also seeDISABLED for a storage engine if the server was compiled to support it, but was started with a--skip-engine_name option. For theNDB storage engine,DISABLED means the server was compiled with support for NDB Cluster, but was not started with the--ndbcluster option.

    All MySQL servers supportMyISAM 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.

  • Savepoints

    Whether the storage engine supports savepoints.

Storage engine information is also available from theINFORMATION_SCHEMAENGINES table. SeeSection 28.3.13, “The INFORMATION_SCHEMA ENGINES Table”.