ob_plan_cache_evict_low_percentage

Description

The ob_plan_cache_evict_low_percentage variable specifies the percentage of the memory size at which plan cache eviction stops, relative to the absolute value of the memory upper limit.

Privilege requirements

• Query variables

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

• 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 memory size at which plan cache eviction stops (the low watermark for plan cache eviction) is calculated as the absolute value of the memory upper limit multiplied by ob_plan_cache_evict_low_percentage divided by 100. For more information about the absolute value of the memory upper limit, see ob_plan_cache_percentage.

Examples

Set the percentage of the memory size at which plan cache eviction stops, relative to the absolute value of the memory upper limit, to 50.

obclient> SET GLOBAL ob_plan_cache_evict_low_percentage =50;