optimizer_use_sql_plan_baselines

Description

The optimizer_use_sql_plan_baselines variable controls whether the optimizer uses a plan baseline.

Required privileges

• Query variables

  • Global level

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

  • Session level

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

• Modify variables

  • Set the variable at the global level

    • sys tenants can directly modify the value of a global system variable.

    • MySQL user tenants must have the SUPER or ALTER SYSTEM privilege to modify the value of a global system variable.

    • Oracle user tenants must have the ALTER SYSTEM privilege to modify the value of a global system variable.

  • Set the variable at the session level

    sys tenants and user tenants can directly modify the value of a session system variable in their own tenant.

Attributes

Examples

Set the optimizer to not use plans in plan baselines.

• Global level

  obclient> SET GLOBAL optimizer_use_sql_plan_baselines = 0;
  

• Session level

  obclient> SET optimizer_use_sql_plan_baselines = 0;