ob_enable_transformation

Description

ob_enable_transformation specifies whether to enable the rewrite feature of the SQL optimizer.

Privilege requirements

• Query variables

  • Global level

    sys and all user tenants can execute the SHOW VARIABLES statement or query the SYS.TENANT_VIRTUAL_GLOBAL_VARIABLE view (Oracle mode) or the information_schema.GLOBAL_VARIABLES view (MySQL mode) to view the values of global system variables.

  • Session level

    sys and all user tenants can execute the SHOW VARIABLES statement or query the SYS.TENANT_VIRTUAL_SESSION_VARIABLE view (Oracle mode) or the information_schema.SESSION_VARIABLES view (MySQL mode) to view the values of session system variables.

• Modify variables

  • Global level

    • sys tenants can directly modify the values of global system variables.

    • MySQL user tenants must have the SUPER or ALTER SYSTEM privilege to modify the values of global system variables.

    • Oracle user tenants must have the ALTER SYSTEM privilege to modify the values of global system variables.

  • Session level

    sys and all user tenants can directly modify the values of session system variables.

Attributes

Examples

Enable the rewrite feature of the SQL optimizer.

• Session level

  obclient> SET ob_enable_transformation =1;
  

• Global level

  obclient> SET GLOBAL ob_enable_transformation =1;