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HeatWave User Guide  /  Reference  /  Secondary Engine Variables

11.8 Secondary Engine Variables

This section describes MySQL DB System variables intended for use with HeatWave.

  • use_secondary_engine

    Introduced 8.0.13
    System Variable use_secondary_engine
    Scope Session
    Dynamic Yes
    SET_VAR Hint Applies Yes
    Type Enumeration
    Default Value ON
    Valid Values

    OFF

    ON

    FORCED

    Whether to execute queries using the secondary engine. These values are permitted:

    • OFF: Queries execute using the primary storage (InnoDB) on the MySQL DB System. Execution using the secondary engine (RAPID) is disabled.

    • ON: Queries execute using the secondary engine (RAPID) when conditions warrant, falling back to the primary storage engine (InnoDB) otherwise. In the case of fallback to the primary engine, whenever that occurs during statement processing, the attempt to use the secondary engine is abandoned and execution is attempted using the primary engine.

    • FORCED: Queries always execute using the secondary engine (RAPID) or fail if that is not possible. Under this mode, a query returns an error if it cannot be executed using the secondary engine, regardless of whether the tables that are accessed have a secondary engine defined.

  • show_create_table_skip_secondary_engine

    Command-Line Format --show-create-table-skip-secondary-engine[={OFF|ON}]
    Introduced 8.0.18
    System Variable show_create_table_skip_secondary_engine
    Scope Session
    Dynamic Yes
    SET_VAR Hint Applies Yes
    Type Boolean
    Default Value OFF

    Whether to exclude the SECONDARY ENGINE clause from SHOW CREATE TABLE output, and from CREATE TABLE statements dumped by the mysqldump utility.

    mysqldump provides the --show-create-skip-secondary-engine option. When specified, it enables the show_create_table_skip_secondary_engine system variable for the duration of the dump operation.

    Attempting a mysqldump operation with the --show-create-skip-secondary-engine option on a MySQL Server release prior to MySQL 8.0.18 that does not support the show_create_table_skip_secondary_engine variable causes an error.