ob_plan_cache_percentage

Description

The ob_plan_cache_percentage variable specifies the percentage of memory that can be used for the plan cache in a tenant.

Privilege requirements

• Query variables

  You 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. This applies to the sys tenant and all user tenants.

• Modify variables

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

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

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

Attributes

Usage notes

The maximum memory that can be used for the plan cache is calculated as follows: Maximum memory for plan cache = Tenant memory limit × ob_plan_cache_percentage/100.

Examples

Set the percentage of memory that can be used for the plan cache to 5.

obclient> SET GLOBAL ob_plan_cache_percentage =5;