New parameter CPU_MIN_COUNT in Oracle Database 19c

Oracle Database 19c has introduced several new features for Multitenant among them we can mention the parameter  CPU_MIN_COUNT that specify a minimum number of CPUs for the PDB. Oracle documentation says the following about this parameter:

CPU_MIN_COUNT specifies the minimum number of CPUs required by a pluggable database (PDB) at any given time.

This parameter specifies the minimum number of CPUs required by a PDB at any given time. For multi-threaded CPUs, this number corresponds to CPU threads, not CPU cores.

You can set this parameter at the CDB level, and for each individual PDB. This enables you to control each PDBs minimum share of CPU utilization within a CDB. If the sum of the CPU_MIN_COUNT values across all open PDBs in a CDB is equal to the value of CPU_MIN_COUNT for the CDB, then the CDB instance is considered full. If the sum exceeds the value of CPU_MIN_COUNT for the CDB, then the CDB instance is over-provisioned. Oracle does not prevent you from over-provisioning a CDB.

Resource Manager is enabled at the CDB level by setting the RESOURCE_MANAGER_PLAN at the root level to the name of a CDB resource plan. If the CDB resource plan has no configured CPU directives, that is, the SHARES and UTILIZATION_LIMIT directives are unset, then Resource Manager uses the CPU_COUNT and CPU_MIN_COUNT settings for the PDB to manage CPU utilization.

 

Reference: https://docs.oracle.com/en/database/oracle/oracle-database/19/refrn/CPU_MIN_COUNT.html#GUID-C0EFFDF8-951A-4C36-B2A9-925AA899647D

 

 

 

 How to change it:

At PDB Level:

SQL> show con_name

CON_NAME
------------------------------
PDB11

SQL> alter system set cpu_min_count=2 scope=both;

System altered.

SQL>

 
SQL> show parameters cpu_min_count

NAME               TYPE        VALUE
------------------ ----------- ------------------------------
cpu_min_count      string      2
SQL>

 At CDB Level: 

SQL>  show con_name

CON_NAME
------------------------------
CDB$ROOT

SQL> alter system set cpu_min_count=2 scope=both;

System altered.

SQL>  show parameters cpu_min_count

NAME               TYPE        VALUE
------------------ ----------- ------------------------------
cpu_min_count      string      1
SQL>