21 Using Oracle Resource Manager for PDBs

Use PL/SQL package procedures to administer Oracle Resource Manager (Resource Manager) to allocate resources to pluggable databases (PDBs) in a multitenant container database (CDB).

This chapter assumes that you meet the following prerequisites:

  • You understand how to configure and manage a CDB.

  • You understand how to use Resource Manager to allocate resources in a non-CDB.

Note:

  • You can complete the tasks in this chapter using SQL*Plus or Oracle SQL Developer.

  • You can also administer the Resource Manager with the graphical user interface of Oracle Enterprise Manager Cloud Control (Cloud Control).

  • For simplicity, this chapter refers to PDBs, application roots, and application PDBs as “PDBs.”

This chapter contains the following topics:

See Also:

21.1 Overview of Oracle Resource Manager in a Multitenant Environment

In a CDB, workloads within multiple PDBs can compete for system and CDB resources. Resource plans solve this problem.

In a multitenant environment, Resource Manager operates on two levels:

  • CDB level

    Resource Manager can manage the workloads for multiple PDBs that are contending for system and CDB resources. You can specify how resources are allocated to PDBs, and you can limit the resource utilization of specific PDBs. The principal tool is a CDB resource plan.

  • PDB level

    Resource Manager can manage the workloads within each PDB. The principal tool is a PDB resource plan.

Resource Manager allocates the resources in two steps:

  1. It allocates a portion of the system's resources to each PDB.

  2. In a specific PDB, it allocates a portion of system resources obtained in the preceding step to each session connected to the PDB.

Note:

Resource Manager manages activity in the root automatically.

To use Resource Manager in a multitenant environment, you must meet the following prerequisites:

  • The CDB must exist and must contain PDBs.

  • To complete a task that uses the DBMS_RESOURCE_MANAGER package, you must have ADMINISTER_RESOURCE_MANAGER system privilege.

This section contains the following topics:

21.1.1 Purpose of Resource Management in a Multitenant Environment

Resource Manager can provide more efficient use of resources for a CDB.

When resource allocation decisions for a CDB are left to the operating system, you may encounter the following problems with workload management:

  • Inappropriate allocation of resources among PDBs

    The operating system distributes resources equally among all active processes and cannot prioritize one task over another. Therefore, one or more PDBs might use an inordinate amount of the system resources, leaving the other PDBs starved for resources.

  • Inappropriate allocation of resources within a single PDB

    One or more sessions connected to a single PDB might use an inordinate amount of the system resources, leaving other sessions connected to the same PDB starved for resources.

  • Inconsistent performance of PDBs

    A single PDB might perform inconsistently when other PDBs are competing for more system resources or less system resources at various times.

  • Lack of resource usage data for PDBs

    Resource usage data is critical for monitoring and tuning PDBs. It might be possible to use operating system monitoring tools to gather the resource usage data for a non-CDB if it is the only database running on the system. However, in a CDB, operating system monitoring tools are no longer as useful because there are multiple PDBs running on the system.

Resource Manager helps to overcome these problems by allowing the CDB more control over how hardware resources are allocated among the PDBs and within PDBs.

In a CDB with multiple PDBs, some PDBs typically are more important than others. The Resource Manager enables you to prioritize and limit the resource usage of specific PDBs. With the Resource Manager, you can:

  • Specify that different PDBs should receive different shares of the system resources so that more resources are allocated to the more important PDBs

  • Limit the CPU usage of a particular PDB

  • Limit the number of parallel execution servers that a particular PDB can use

  • Limit the memory usage of a particular PDB

  • Specify the amount of memory guaranteed for a particular PDB

  • Specify the maximum amount of memory a particular PDB can use

  • Use PDB performance profiles for different sets of PDB

    A performance profile for a set of PDBs can specify shares of system resources, CPU usage, and number of parallel execution servers. PDB performance profiles enable you to manage resources for large numbers of PDBs by specifying Resource Manager directives for profiles instead of individual PDBs.

  • Limit the resource usage of different sessions connected to a single PDB

  • Limit the I/O generated by specific PDBs

  • Monitor the resource usage of PDBs

21.1.2 Overview of Resource Plan Directives

A CDB resource plan allocates resources to its PDBs according to its set of resource plan directives (directives).

A parent-child relationship exists between a CDB resource plan and its resource plan directives. Each directive references either a set of PDBs in a performance profile, or a single PDB.

You can specify directives for both individual PDBs and for PDB performance profiles in the same CDB. No two directives for the currently active plan can reference the same PDB or the same PDB performance profile.

This section contains the following topics:

21.1.2.1 PDB Performance Profiles

A PDB performance profile configures resource plan directives for a set of PDBs that have the same priorities and resource controls.

For example, you might create a performance profiles called Gold, Silver, and Bronze. Each profile specifies a different set of directives depending on the importance of the type of PDB. Gold PDBs are more mission critical than Silver PDBs, which are more mission critical than Bronze PDBs. A PDB specifies its performance profile with the DB_PERFORMANCE_PROFILE initialization parameter.

You can use PDB lockdown profiles to specify PDB initialization parameters that control resources, such as SGA_TARGET and PGA_AGGREGATE_LIMIT. A lockdown profile prevents the PDB administrator from modifying the settings.

Oracle recommends using matching names for performance profiles and lockdown profiles. To prevent PDB owners from switching profiles, Oracle recommends putting the PDB performance profile in the PDB lockdown profile.

21.1.2.2 Resource Plan Directives

Directives control allocation of CPU and parallel execution servers.

A directive can control the allocation of resources to PDBs based on the share value that you specify for each PDB or PDB performance profile. A higher share value results in more resources. For example, you can specify that one PDB is allocated double the resources allocated to a second PDB by setting the share value for the first PDB twice as high as the share value for the second PDB. Similarly, you can specify that one PDB performance profile is allocated double the resources allocated to a second PDB performance profile by setting the share value for the first PDB performance profile twice as high as the share value for the second PDB performance profile. The settings apply to the set of PDBs that use each profile.

You can also specify utilization limits for PDBs and PDB performance profiles. The limit controls allocation to the PDB or performance profile. For example, the limit can control how much CPU a PDB gets as a percentage of the total CPU available to the CDB.

You can use both shares and utilization limits together for precise control over the resources allocated to each PDB and PDB performance profile in a CDB.

See Also:

"About Restricting PDB Users for Enhanced Security" for more information about PDB lockdown profiles

21.1.3 Background and Administrative Tasks and Consumer Groups

In a CDB, background and administrative tasks map to the Resource Manager consumer groups that run them optimally.

Resource Manager uses the following rules to map a task to a consumer group:

  • A task is mapped to a consumer group in the container that starts the task.

    If a task starts in the CDB root, then the task maps to a consumer group in the CDB root. If the task starts in a PDB, then the task maps to a consumer group in the PDB.

  • Many maintenance and administrative tasks automatically map to a consumer group.

    For example, automated maintenance tasks map to ORA$AUTOTASK. In certain cases, the tasks map to a consumer group, but the mapping is modifiable. Such tasks include RMAN backup, RMAN image copy, Oracle Data Pump, and In-Memory population.

Note:

Oracle Database Administrator’s Guide to learn more about the mapping rules for predefined consumer groups

21.1.4 Initialization Parameters for Multitenant Resource Management

Use initialization parameters for control memory and I/O in a PDB.

This section contains the following topics:

21.1.4.1 Memory-Related Initialization Parameters for PDBs

Several initialization parameters control the memory usage of a PDB.

When the PDB is the current container, the initialization parameters in the following table control the memory usage of the current PDB. When one or more of these parameters is set for a PDB, ensure that the CDB and the other PDBs have sufficient memory for their operations. The initialization parameters control the memory usage of PDBs only if the following conditions are met:

  • The
    NONCDB_COMPATIBLE
    initialization parameter is set to
    false
    in the CDB root.
  • The
    MEMORY_TARGET
    initialization parameter is not set or is set to
    0
    (zero) in the CDB root.

Table 21-1 Initialization Parameters That Control the Memory Usage of PDBs

Initialization Parameter Description
DB_CACHE_SIZE

Sets the minimum, guaranteed buffer cache space for the PDB.

The following requirements must be met:

  • It must be less than or equal to 50% of the setting for the
    DB_CACHE_SIZE
    in the CDB root.
  • The sum of the
    DB_CACHE_SIZE
    settings for all PDBs must be less than or equal to 50% of the setting for the
    DB_CACHE_SIZE
    in the CDB root.
These requirements do not apply if the
SGA_TARGET
initialization parameter is set to a nonzero value in the CDB root.
When the
SGA_TARGET
initialization parameter is set to a nonzero, the following requirements must be met:
  • The values of
    DB_CACHE_SIZE
    plus
    SHARED_POOL_SIZE
    in a PDB must be less than or equal to 50% of the PDB’s
    SGA_TARGET
    value.
  • The values of
    DB_CACHE_SIZE
    plus
    SHARED_POOL_SIZE
    in a PDB must be less than or equal to 50% of the
    SGA_TARGET
    value at the CDB level.
  • The sum of
    DB_CACHE_SIZE
    plus
    SHARED_POOL_SIZE
    across all the PDBs in a CDB must be less than or equal to 50% of the
    SGA_TARGET
    value at the CDB level.
SHARED_POOL_SIZE

Sets the minimum, guaranteed shared pool space for the PDB.

The following requirements must be met:

  • It must be less than or equal to 50% of the setting for the
    SHARED_POOL_SIZE
    in the CDB root.
  • The sum of the
    SHARED_POOL_SIZE
    settings for all PDBs must be less than or equal to 50% of the setting for the
    SHARED_POOL_SIZE
    in the CDB root.
These requirements do not apply if the
SGA_TARGET
initialization parameter is set to a nonzero value in the CDB root.
When the
SGA_TARGET
initialization parameter is set to a nonzero, the following requirements must be met:
  • The values of
    DB_CACHE_SIZE
    plus
    SHARED_POOL_SIZE
    in a PDB must be less than or equal to 50% of the PDB’s
    SGA_TARGET
    value.
  • The values of
    DB_CACHE_SIZE
    plus
    SHARED_POOL_SIZE
    in a PDB must be less than or equal to 50% of the
    SGA_TARGET
    value at the CDB level.
  • The sum of
    DB_CACHE_SIZE
    plus
    SHARED_POOL_SIZE
    across all the PDBs in a CDB must be less than or equal to 50% of the
    SGA_TARGET
    value at the CDB level.
SGA_MIN_SIZE

Sets the minimum SGA size for the PDB.

The following requirements must be met:

  • It must be less than or equal to 50% of the setting for the
    SGA_TARGET
    in the CDB root.
  • It must be less than or equal to 50% of the setting for the
    SGA_TARGET
    in the PDB.
  • The sum of the
    SGA_MIN_SIZE
    settings for all PDBs must be less than or equal to 50% of the setting for the
    SGA_TARGET
    in the CDB root.
These requirements do not apply if the
SGA_TARGET
initialization parameter is not set or is set to
0
(zero) in the CDB root.
SGA_TARGET

Sets the maximum SGA size for the PDB.

The
SGA_TARGET
setting in the PDB is enforced only if the
SGA_TARGET
initialization parameter is set to a nonzero value in the CDB root. The
SGA_TARGET
setting in the PDB must be less than or equal to the
SGA_TARGET
setting in the CDB root.
PGA_AGGREGATE_LIMIT

Sets the maximum PGA size for the PDB.

The following requirements must be met:

  • It must be less than or equal to the setting for the
    PGA_AGGREGATE_LIMIT
    in the CDB root.
  • It must be greater than or equal to two times the setting for the
    PGA_AGGREGATE_TARGET
    in the PDB.
PGA_AGGREGATE_TARGET

Sets the target aggregate PGA size for the PDB.

The following requirements must be met:

  • It must be less than or equal to the
    PGA_AGGREGATE_TARGET
    value set at the CDB level.
  • It must be less than or equal to 50% of the
    PGA_AGGREGATE_LIMIT
    initialization parameter value set at the CDB level.
  • It must be less than or equal to 50% of the
    PGA_AGGREGATE_LIMIT
    value set in the PDB.

Example 21-1 Setting the Maximum Aggregate PGA Memory Available for a PDB

With the PDB as the current container, run the following SQL statement to set he
PGA_AGGREGATE_LIMIT
initialization parameter both in memory and in the SPFILE to 90 megabytes:
ALTER SYSTEM SET PGA_AGGREGATE_LIMIT = 90M SCOPE = BOTH;

Example 21-2 Setting the Minimum SGA Size for a PDB

With the PDB as the current container, run the following SQL statement to set the
SGA_MIN_SIZE
initialization parameter both in memory and in the SPFILE to 500 megabytes:
ALTER SYSTEM SET SGA_MIN_SIZE = 500M SCOPE = BOTH;
21.1.4.2 I/O-Related Initialization Parameters for PDBs

The MAX_IOPS and MAX_MBPS initialization parameters limit the disk I/O generated by a PDB.

A large amount of disk I/O can cause poor performance. Several factors can result in excess disk I/O, such as poorly designed SQL or index and table scans in high-volume transactions. If one PDB is generating a large amount of disk I/O, then it can degrade the performance of other PDBs in the same CDB.

Use one or both of the following initialization parameters to limit the I/O generated by a specific PDB:

  • The MAX_IOPS initialization parameter limits the number of I/O operations for each second.

  • The MAX_MBPS initialization parameter limits the megabytes for I/O operations for each second.

If you set both preceding initialization parameters for a single PDB, then Oracle Database enforces both limits. Note that these limits are not enforced for Oracle Exadata, which uses I/O Resource Management (IORM) to manage I/Os between PDBs.

If these initialization parameters are set with the CDB root as the current container, then the values become the default values for all containers in the CDB. If they are set with an application root as the current container, then the values become the default values for all application PDBs in the application container. When they are set with a PDB or application PDB as the current container, then the settings take precedence over the default settings in the CDB root or the application root. These parameters cannot be set in a non-CDB.

The default for both initialization parameters is 0 (zero). If these initialization parameters are set to 0 (zero) in a PDB, and the CDB root is set to 0, then there is no I/O limit for the PDB. If these initialization parameters are set to 0 (zero) in an application PDB, and its application root is set to 0, then there is no I/O limit for the application PDB.

Critical I/O operations, such as ones for the control file and password file, are exempted from the limit and continue to run even if the limit is reached. However, all I/O operations, including critical I/O operations, are counted when the number of I/O operations and the megabytes for I/O operations are calculated.

You can use the DBA_HIST_RSRC_PDB_METRIC view to calculate a reasonable I/O limit for a PDB. Consider the values in the following columns when calculating a limit: IOPS, IOMBPS, IOPS_THROTTLE_EXEMPT, and IOMBPS_THROTTLE_EXEMPT. The rsmgr:io rate limit wait event indicates that a limit was reached.

Example 21-3 Limiting the I/O Generated by a PDB

With the PDB as the current container, run the following SQL statement to set the MAX_IOPS initialization parameter both in memory and in the SPFILE to a limit of 1,000 I/O operations for each second:

ALTER SYSTEM SET MAX_IOPS = 1000 SCOPE = BOTH;

Example 21-4 Limiting the Megabytes of I/O Generated by a PDB

With the PDB as the current container, run the following SQL statement to set the MAX_MBPS initialization parameter both in memory and in the SPFILE to a limit of 200 MB of I/O for each second:

ALTER SYSTEM SET MAX_MBPS = 200 SCOPE = BOTH;

See Also:

21.1.4.3 CPU-Related Initialization Parameters for PDBs

The CPU_COUNT initialization parameter specifies the number of CPUs available for Oracle Database to use.

Instance caging is a technique that uses an initialization parameter to limit the number of CPUs that an instance can use simultaneously. You can set CPU_COUNT at the PDB level. If Resource Manager is enabled, then the PDB is “caged” (restricted) to the number of CPUs specified by CPU_COUNT.

CPU_COUNT works the same way as the utilization_limit directive in the CDB plan. However, the CPU_COUNT limit is expressed in terms of number of CPUs rather than utilization percentage. If both the utilization_limit and CPU_COUNT are specified, then the lower limit is enforced.

CPU_COUNT is advantageous because when the PDB is plugged into a new container, the CPU_COUNT setting remains with the plugged-in PDB. Also, Oracle Database uses the CPU_COUNT setting for a PDB to derive many other PDB parameters, such as those for parallel execution.

21.2 Managing CDB Resource Plans

In a CDB, PDBs might have different levels of priority. You can create CDB resource plans to distribute resources to different PDBs based on these priorities.

This section contains the following topics:

21.2.1 About CDB Resource Plans

Create CDB resource plans that allocate shares and resource limits for PDBs.

This section contains the following topics:

21.2.1.1 Shares for Allocating Resources to PDBs

To allocate resources among PDBs, assign a share value to each PDB or performance profile. A higher share value results in more guaranteed resources for a PDB or the PDBs that use the performance profile.

Specify a share value for a PDB using the DBMS_RESOURCE_MANAGER.CREATE_CDB_PLAN_DIRECTIVE procedure and for a PDB performance profile using the DBMS_RESOURCE_MANAGER.CREATE_CDB_PROFILE_DIRECTIVE procedure. In both cases, the shares parameter specifies the share value for the PDB. Multiple PDBs can use the same PDB performance profile.

The following figure shows an example of three PDBs with share values specified for them in a CDB resource plan.

Figure 21-1 Shares in a CDB Resource Plan

Description of Figure 21-1 follows
Description of "Figure 21-1 Shares in a CDB Resource Plan"

The preceding figure shows that the total number of shares is seven (3 plus 3 plus 1). The salespdb and the servicespdb PDB are each guaranteed 3/7 of the resources, while the hrpdb PDB is guaranteed 1/7 of the resources. However, any PDB can use more than the guaranteed amount of a resource when no resource contention exists.

The following table shows the resource allocation to the PDBs in the preceding figure based on the share values. The table assumes that loads of the PDBs consume all system resources allocated.

Table 21-2 Resource Allocation for Sample PDBs

Resource Resource Allocation See Also

CPU

The salespdb and servicespdb PDBs can consume the same amount of CPU resources. The salespdb and servicespdb PDBs are each guaranteed three times more CPU resource than the hrpdb PDB.

Oracle Database Administrator’s Guide for more information about this resource

Parallel execution servers

Queued parallel queries from the salespdb and servicespdb PDBs are selected equally. Queued parallel queries from the salespdb and servicespdb PDBs are selected three times as often as queued parallel queries from the hrpdb PDB.

Oracle Database Administrator’s Guide for more information about this resource

21.2.1.2 Utilization Limits for PDBs

A utilization limit restrains the system resource usage of a specific PDB or a specific PDB performance profile.

You can specify utilization limits for CPU and parallel execution servers. Utilization limits for a PDB are set by the CDB resource plan.

The following table describes utilization limits for PDBs and the Resource Manager action taken when a PDB reaches a utilization limit. For limits specified with a PDB performance profile, the limit applies to every PDB that uses the PDB performance profile. For example, if pdb1 and pdb20 have a performance profile BRONZE, and if BRONZE has a limit set to 10%, then pdb1 has a 10% limit and pdb20 has a 10% limit.

Table 21-3 Utilization Limits for PDBs

Resource Resource Utilization Limit Resource Manager Action When Limit Is Reached

CPU

The CPU utilization limit for sessions connected to a PDB is set by the utilization_limit parameter in subprograms of the DBMS_RESOURCE_MANAGER package. The utilization_limit parameter specifies the percentage of the system resources that a PDB can use. The value ranges from 0 to 100.

You can also limit CPU for a PDB by setting the initialization parameter CPU_COUNT. For example, if you set the CPU_COUNT to 8, then the PDB cannot use more than 8 CPUs at any time. If both utilization_limit and CPU_COUNT are specified, then the more restrictive (lower) value is enforced.

Resource Manager throttles the PDB sessions so that the CPU utilization for the PDB does not exceed the utilization limit.

Parallel execution servers

You can limit the number of parallel execution servers in a PDB by means of parallel statement queuing. The limit is a “queuing point” because the database queues parallel queries when the limit is reached.

You can set the limit (queuing point) in either of the following ways:

  • The value of the PARALLEL_SERVERS_TARGET initialization parameter setting in the PDB

  • The value of the PARALLEL_SERVERS_TARGET initialization parameter setting in the CDB root multiplied by the value of the parallel_server_limit directive set for the PDB in the CDB resource manager plan

    For example, if the PARALLEL_SERVERS_TARGET initialization parameter is set to 200 in the CDB root, and if the parallel_server_limit directive for a PDB is set to 10%, then utilization limit for the PDB is 20 parallel execution servers (200 * .10).

If the limit is set in both preceding ways, then the lower limit of the two is used. See Oracle Database Reference for the default value for PARALLEL_SERVERS_TARGET.

Note: Oracle recommends using the PARALLEL_SERVERS_TARGET initialization parameter instead of the parallel_server_limit directive in a CDB plan.

Resource Manager queues parallel queries when the number of parallel execution servers used by the PDB would exceed the limit.

Note: In a CDB, parallel statements are queued based on the PARALLEL_SERVERS_TARGET settings at both the PDB and CDB level. A statement is queued when the number of parallel servers used by the PDB exceeds the target for the PDB or when the number of parallel servers used by all PDBs exceeds the target for the CDB.

The following figure shows an example of three PDBs with shares and utilization limits specified for them in a CDB resource plan.

Figure 21-2 Shares and Utilization Limits in a CDB Resource Plan

Description of Figure 21-2 follows
Description of "Figure 21-2 Shares and Utilization Limits in a CDB Resource Plan"

The preceding figure shows that there are no utilization limits on the salespdb and servicespdb PDBs because utilization_limit and parallel_server_limit are both set to 100% for them. However, the hrpdb PDB is limited to 70% of the applicable system resources because utilization_limit and parallel_server_limit are both set to 70%.

Note:

This scenario assumes that the PARALLEL_SERVERS_TARGET initialization parameter does not specify a lower limit in a PDB. When the PARALLEL_SERVERS_TARGET initialization parameter specifies a lower limit for parallel execution servers in a PDB, the lower limit is used.

21.2.1.3 The Default Directive for PDBs

When you do not explicitly define directives for a PDB, the PDB uses the default directive for PDBs.

The following table shows the attributes of the initial default directive for PDBs.

Table 21-4 Initial Default Directive Attributes for PDBs

Directive Attribute Value

shares

1

utilization_limit

100

parallel_server_limit

100

When a PDB is plugged into a CDB and no directive is defined for it, the PDB uses the default directive for PDBs.

You can create new directives for the new PDB. You can also change the default directive attribute values for PDBs by using the UPDATE_CDB_DEFAULT_DIRECTIVE procedure in the DBMS_RESOURCE_MANAGER package.

When a PDB is unplugged from a CDB, the directive for the PDB is retained. If the same PDB is plugged back into the CDB, then it uses the directive defined for it if the directive was not deleted manually.

Figure 21-3 shows an example of the default directive in a CDB resource plan.

Figure 21-3 Default Directive in a CDB Resource Plan

Description of Figure 21-3 follows
Description of "Figure 21-3 Default Directive in a CDB Resource Plan"

Figure 21-3 shows that the default PDB directive specifies that the share is 1, the utilization_limit is 50%, and the parallel_server_limit is 50%. Any PDB that is part of the CDB and does not have directives defined for it uses the default PDB directive. Figure 21-3 shows the PDBs marketingpdb and testingpdb using the default PDB directive. Therefore, marketingpdb and testingpdb each get 1 share and utilization limits of 50.

21.2.2 Creating a CDB Resource Plan for Managing PDBs

To create a CDB resource plan for individual PDBs and define the directives for the plan, use the DBMS_RESOURCE_MANAGER package.

The general steps for creating a CDB resource plan for individual PDBs are the following:

  1. Create the pending area using the CREATE_PENDING_AREA procedure.
  2. Create the CDB resource plan using the CREATE_CDB_PLAN procedure.
  3. Create directives for the PDBs using the CREATE_CDB_PLAN_DIRECTIVE procedure.
  4. (Optional) Update the default PDB directive using the UPDATE_CDB_DEFAULT_DIRECTIVE procedure.
  5. Validate the pending area using the VALIDATE_PENDING_AREA procedure.
  6. Submit the pending area using the SUBMIT_PENDING_AREA procedure.

21.2.3 Creating a CDB Resource Plan for Managing PDBs: Scenario

This scenario illustrates each of the steps involved in creating a CDB resource plan for individual PDBs.

The scenario assumes that you want to create a CDB resource plan for a CDB named newcdb. The plan includes a directive for each PDB. In this scenario, you also update the default directive and the AutoTask directive.

The directives are defined using various procedures in the DBMS_RESOURCE_MANAGER package. The attributes of each directive are defined using parameters in these procedures. Table 21-5 describes the types of directives in the plan.

Table 21-5 Attributes for PDB Directives in a CDB Resource Plan

Directive Attribute Description See Also

shares

Resource allocation share for CPU and parallel execution server resources.

"Shares for Allocating Resources to PDBs"

utilization_limit

Resource utilization limit for CPU.

"Utilization Limits for PDBs"

parallel_server_limit

Maximum percentage of parallel execution servers that a PDB can use before queuing parallel statements.

When the parallel_server_limit directive is specified for a PDB, the limit is the PARALLEL_SERVERS_TARGET value of the CDB root multiplied by the value of the parallel_server_limit parameter in the CREATE_CDB_PLAN_DIRECTIVE procedure.

Note: Oracle recommends using the PARALLEL_SERVERS_TARGET initialization parameter instead of the parallel_server_limit directive in a CDB plan.

"Utilization Limits for PDBs"

Table 21-6 describes how the CDB resource plan allocates resources to its PDBs using the directive attributes described in Table 21-5.

Table 21-6 Sample Directives for PDBs in a CDB Resource Plan

PDB shares Directive utilization_limit Directive parallel_server_limit Directive

salespdb

3

Unlimited

Unlimited

servicespdb

3

Unlimited

Unlimited

hrpdb

1

70

70

Default

1

50

50

AutoTask

1

75

75

The salespdb and servicespdb PDBs are more important than the other PDBs in the CDB. Therefore, they get a higher share (3), unlimited CPU utilization resource, and unlimited parallel execution server resource.

The default directive applies to PDBs for which specific directives have not been defined. For this scenario, assume that the CDB has several PDBs that use the default directive. This scenario updates the default directive.

In addition, this scenario updates the AutoTask directive. The AutoTask directive applies to automatic maintenance tasks that are run in the root maintenance window.

To create a CDB resource plan:

  1. Create a pending area using the CREATE_PENDING_AREA procedure:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
  2. Create a CDB resource plan named newcdb_plan using the CREATE_CDB_PLAN procedure:

    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PLAN(
        plan    => 'newcdb_plan',
        comment => 'CDB resource plan for newcdb');
    END;
    /
  3. Create the CDB resource plan directives for the PDBs using the CREATE_CDB_PLAN_DIRECTIVE procedure. Each directive specifies how resources are allocated to a specific PDB.

    Table 21-6 describes the directives for the salespdb, servicespdb, and hrpdb PDBs in this scenario. Run the following procedures to create these directives:

    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PLAN_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        pluggable_database    => 'salespdb', 
        shares                => 3, 
        utilization_limit     => 100,
        parallel_server_limit => 100);
    END;
    /
    
    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PLAN_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        pluggable_database    => 'servicespdb', 
        shares                => 3, 
        utilization_limit     => 100,
        parallel_server_limit => 100);
    END;
    /
    
    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PLAN_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        pluggable_database    => 'hrpdb', 
        shares                => 1, 
        utilization_limit     => 70,
        parallel_server_limit => 70);
    END;
    /
    

    All other PDBs in this CDB use the default PDB directive.

  4. If the current default CDB resource plan directive for PDBs does not meet your requirements, then update the directive using the UPDATE_CDB_DEFAULT_DIRECTIVE procedure.

    The default directive applies to PDBs for which specific directives have not been defined. See "The Default Directive for PDBs" for more information.

    Table 21-6 describes the default directive that PDBs use in this scenario. Run the following procedure to update the default directive:

    BEGIN
      DBMS_RESOURCE_MANAGER.UPDATE_CDB_DEFAULT_DIRECTIVE(
        plan                      => 'newcdb_plan', 
        new_shares                => 1, 
        new_utilization_limit     => 50,
        new_parallel_server_limit => 50);
    END;
    /
  5. Validate the pending area using the VALIDATE_PENDING_AREA procedure:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
  6. Submit the pending area using the SUBMIT_PENDING_AREA procedure:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();

21.2.4 Creating a CDB Resource Plan with PDB Performance Profiles

Use the DBMS_RESOURCE_MANAGER package to create a CDB resource plan for PDB performance profiles and define the directives for the plan. Each PDB that uses a profile adopts the CDB resource plan directive.

The general steps for creating a CDB resource plan with PDB performance profiles are the following:

  1. Create the pending area using the CREATE_PENDING_AREA procedure.
  2. Create the CDB resource plan using the CREATE_CDB_PLAN procedure.
  3. Create directives for the PDB performance profiles using the CREATE_CDB_PROFILE_DIRECTIVE procedure.
  4. (Optional) Update the default PDB directive using the UPDATE_CDB_DEFAULT_DIRECTIVE procedure.
  5. Validate the pending area using the VALIDATE_PENDING_AREA procedure.
  6. Submit the pending area using the SUBMIT_PENDING_AREA procedure.
  7. For each PDB that will use a profile, set the DB_PERFORMANCE_PROFILE initialization parameter and specify the profile name.

21.2.5 Creating a CDB Resource Plan for PDB Performance Profiles: Scenario

This scenario illustrates the steps involved in creating a CDB resource plan for PDB performance profiles.

The scenario assumes that you want to create a CDB resource plan for a CDB named newcdb. The plan includes a directive for each PDB performance profile. In this scenario, you also update the default directive and the AutoTask directive.

In the CDB resource plan, you give each profile a name. In each PDB, you set the DB_PERFORMANCE_PROFILE initialization parameter to specify which PDB performance profile the PDB uses.

The directives are defined using various procedures in the DBMS_RESOURCE_MANAGER package. The attributes of each directive are defined using parameters in these procedures. The following table describes the types of directives in the plan.

Table 21-7 Attributes for PDB Performance Profile Directives in a CDB Resource Plan

Directive Attribute Description See Also

shares

Resource allocation share for CPU and parallel execution server resources.

"Shares for Allocating Resources to PDBs"

utilization_limit

Resource utilization limit for CPU.

"Utilization Limits for PDBs"

parallel_server_limit

Maximum percentage of parallel execution servers that a PDB can use.

When the parallel_server_limit directive is specified for a PDB performance profile, the limit is the value of the PARALLEL_SERVERS_TARGET initialization parameter setting in the CDB root multiplied by the value of the parallel_server_limit parameter in the CREATE_CDB_PROFILE_DIRECTIVE procedure.

"Utilization Limits for PDBs"

The following table describes how the CDB resource plan allocates resources to its PDB performance profiles using the directive attributes described in Table 21-7.

Table 21-8 Sample Directives for PDB Performance Profiles in a CDB Resource Plan

PDB shares Directive utilization_limit Directive parallel_server_limit Directive

gold

3

Unlimited

Unlimited

silver

2

40

40

bronze

1

20

20

Default

1

10

10

AutoTask

2

60

60

The default directive applies to PDBs for which specific directives have not been defined. For this scenario, assume that the CDB has several PDBs that use the default directive. This scenario updates the default directive.

In addition, this scenario updates the AutoTask directive. The AutoTask directive applies to automatic maintenance tasks that are run in the root maintenance window.

To create a CDB resource plan for PDB performance profiles:

  1. For each PDB that will use a profile, set the DB_PERFORMANCE_PROFILE initialization parameter to the name of the profile that the PDB will use.

    1. Run an ALTER SYSTEM statement to set the parameter.

      For example, with the PDB as the current container, run the following SQL statement:

      ALTER SYSTEM SET DB_PERFORMANCE_PROFILE=gold SCOPE=spfile;
    2. Close the PDB:

      ALTER PLUGGABLE DATABASE CLOSE IMMEDIATE;
    3. Open the PDB:

      ALTER PLUGGABLE DATABASE OPEN;
  2. Create a pending area using the CREATE_PENDING_AREA procedure:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
  3. Create a CDB resource plan named newcdb_plan using the CREATE_CDB_PLAN procedure:

    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PLAN(
        plan    => 'newcdb_plan',
        comment => 'CDB resource plan for newcdb');
    END;
    /
  4. Create the CDB resource plan directives for the PDBs using the CREATE_CDB_PLAN_DIRECTIVE procedure. Each directive specifies how resources are allocated to a specific PDB.

    Table 21-6 describes the directives for the gold, silver, and bronze profiles in this scenario. Run the following procedures to create these directives:

    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PROFILE_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        profile               => 'gold', 
        shares                => 3, 
        utilization_limit     => 100,
        parallel_server_limit => 100);
    END;
    /
    
    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PROFILE_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        profile               => 'silver', 
        shares                => 2, 
        utilization_limit     => 40,
        parallel_server_limit => 40);
    END;
    /
    
    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PROFILE_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        profile               => 'bronze', 
        shares                => 1, 
        utilization_limit     => 20,
        parallel_server_limit => 20);
    END;
    /
    

    All other PDBs in this CDB use the default PDB directive.

  5. If the current default CDB resource plan directive for PDBs does not meet your requirements, then update the directive using the UPDATE_CDB_DEFAULT_DIRECTIVE procedure.

    The default directive applies to PDBs for which specific directives have not been defined.

    Table 21-6 describes the default directive that PDBs use in this scenario. Run the following procedure to update the default directive:

    BEGIN
      DBMS_RESOURCE_MANAGER.UPDATE_CDB_DEFAULT_DIRECTIVE(
        plan                      => 'newcdb_plan', 
        new_shares                => 1, 
        new_utilization_limit     => 10,
        new_parallel_server_limit => 10);
    END;
    /
  6. Validate the pending area using the VALIDATE_PENDING_AREA procedure:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
  7. Submit the pending area using the SUBMIT_PENDING_AREA procedure:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();

21.2.6 Enabling a CDB Resource Plan

You enable the Resource Manager for a CDB by setting the RESOURCE_MANAGER_PLAN initialization parameter in the root.

This parameter specifies the top plan, which is the plan to be used for the current CDB instance. If no plan is specified with this parameter, then the Resource Manager is not enabled.

Prerequisites

Before enabling a CDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To enable a CDB resource plan:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Perform one of the following actions:

    • Use an ALTER SYSTEM statement to set the RESOURCE_MANAGER_PLAN initialization parameter to the CDB resource plan.

      The following example sets the CDB resource plan to newcdb_plan using an ALTER SYSTEM statement:

      ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = 'newcdb_plan';
      
    • In a text initialization parameter file, set the RESOURCE_MANAGER_PLAN initialization parameter to the CDB resource plan, and restart the CDB.

      The following example sets the CDB resource plan to newcdb_plan in an initialization parameter file:

      RESOURCE_MANAGER_PLAN = 'newcdb_plan'
      

See Also:

21.2.7 Modifying a CDB Resource Plan

Modifying a CDB resource plan includes tasks such as updating the plan, creating, updating, or deleting plan directives for PDBs, and updating default directives.

This section contains the following topics:

21.2.7.1 Updating a CDB Resource Plan

You can update a CDB resource plan to change its comment using the UPDATE_CDB_PLAN procedure.

Prerequisites

Before updating a CDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To update a CDB resource plan:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the UPDATE_CDB_PLAN procedure, and enter a new comment in the new_comment parameter.

    For example, the following procedure changes the comment for the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.UPDATE_CDB_PLAN(
        plan        => 'newcdb_plan',
        new_comment => 'CDB plan for PDBs in newcdb');
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    
21.2.7.2 Managing CDB Resource Plan Directives for a PDB

You can create, update, and delete CDB resource plan directives for a PDB.

This section contains the following topics:

21.2.7.2.1 Creating New CDB Resource Plan Directives for a PDB

When you create a PDB in a CDB, you can create a CDB resource plan directive for the PDB using the CREATE_CDB_PLAN_DIRECTIVE procedure. The directive specifies how resources are allocated to the new PDB.

Prerequisites

Before creating a new CDB resource plan directive for a PDB, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To create a new CDB resource plan directive for a PDB:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the CREATE_CDB_PLAN_DIRECTIVE procedure, and specify the appropriate values for the new PDB.

    For example, the following procedure allocates resources to a PDB named operpdb in the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PLAN_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        pluggable_database    => 'operpdb', 
        shares                => 1, 
        utilization_limit     => 20,
        parallel_server_limit => 30);
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    
21.2.7.2.2 Updating CDB Resource Plan Directives for a PDB

You can update the CDB resource plan directive for a PDB using the UPDATE_CDB_PLAN_DIRECTIVE procedure. The directive specifies how resources are allocated to the PDB.

Prerequisites

Before updating a CDB resource plan directive for a PDB, ensure that you meet the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To update a CDB resource plan directive for a PDB:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the UPDATE_CDB_PLAN_DIRECTIVE procedure, and specify the new resource allocation values for the PDB.

    For example, the following procedure updates the resource allocation to a PDB named operpdb in the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.UPDATE_CDB_PLAN_DIRECTIVE(
        plan                      => 'newcdb_plan', 
        pluggable_database        => 'operpdb', 
        new_shares                => 1, 
        new_utilization_limit     => 10,
        new_parallel_server_limit => 20);
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    
21.2.7.2.3 Deleting CDB Resource Plan Directives for a PDB

You can delete the CDB resource plan directive for a PDB using the DELETE_CDB_PLAN_DIRECTIVE procedure.

You might delete the directive for a PDB if you unplug or drop the PDB. However, you can retain the directive, and if the PDB is plugged into the CDB in the future, the existing directive applies to the PDB.

Prerequisites

Before deleting a CDB resource plan directive for a PDB, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To delete a CDB resource plan directive for a PDB:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the DELETE_CDB_PLAN_DIRECTIVE procedure, and specify the CDB resource plan and the PDB.

    For example, the following procedure deletes the directive for a PDB named operpdb in the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.DELETE_CDB_PLAN_DIRECTIVE(
        plan               => 'newcdb_plan', 
        pluggable_database => 'operpdb');
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    
21.2.7.3 Managing CDB Resource Plan Directives for a PDB Performance Profile

You can create, update, and delete CDB resource plan directives for a PDB performance profile.

This section contains the following topics:

21.2.7.3.1 Creating New CDB Resource Plan Directives for a PDB Performance Profile

You can create a CDB resource plan directive for the a new PDB performance profile using the CREATE_CDB_PROFILE_DIRECTIVE procedure. The directive specifies how resources are allocated to the all PDBs that use the new profile.

Prerequisites

Before creating a new CDB resource plan directive for a PDB performance profile, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To create a new CDB resource plan directive for a PDB performance profile:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the CREATE_CDB_PROFILE_DIRECTIVE procedure, and specify the appropriate values for the new PDB performance profile.

    For example, the following procedure allocates resources to a PDB performance profile named copper in the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.CREATE_CDB_PROFILE_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        profile               => 'copper', 
        shares                => 1, 
        utilization_limit     => 20,
        parallel_server_limit => 30);
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    

Note:

For a PDB to use the new profile, the PDB must have the DB_PERFORMANCE_PROFILE initialization parameter set to the profile name.
21.2.7.3.2 Updating CDB Resource Plan Directives for a PDB Performance Profile

Update the CDB resource plan directive for a PDB performance profile using the UPDATE_CDB_PROFILE_DIRECTIVE procedure. The directive specifies how resources are allocated to the PDBs that use the PDB performance profile.

Before updating a CDB resource plan directive for a PDB performance profile, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To update a CDB resource plan directive for a PDB performance profile:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the UPDATE_CDB_PROFILE_DIRECTIVE procedure, and specify the new resource allocation values for the PDB performance profile.

    For example, the following procedure updates the resource allocation for a PDB performance profile named copper in the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.UPDATE_CDB_PROFILE_DIRECTIVE(
        plan                      => 'newcdb_plan', 
        profile                   => 'copper', 
        new_shares                => 1, 
        new_utilization_limit     => 10,
        new_parallel_server_limit => 20);
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    
21.2.7.3.3 Deleting CDB Resource Plan Directives for a PDB Performance Profile

You can delete the CDB resource plan directive for a PDB performance profile using the DELETE_CDB_PROFILE_DIRECTIVE procedure.

If no PDBs use a performance profile, then you might delete the directive for the profile.

Prerequisites

Before deleting a CDB resource plan directive for a PDB performance profile, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To delete a CDB resource plan directive for a PDB performance profile:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the DELETE_CDB_PROFILE_DIRECTIVE procedure, and specify the CDB resource plan and the PDB performance profile.

    For example, the following procedure deletes the directive for a PDB named operpdb in the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.DELETE_CDB_PLAN_DIRECTIVE(
        plan    => 'newcdb_plan', 
        profile => 'operpdb');
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    
21.2.7.4 Updating the Default Directive for PDBs in a CDB Resource Plan

You can update the default directive for PDBs in a CDB resource plan using the UPDATE_CDB_DEFAULT_DIRECTIVE procedure. The default directive applies to PDBs for which specific directives have not been defined.

Prerequisites

Before updating the default directive for PDBs in a CDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To update the default directive for PDBs in a CDB resource plan:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the UPDATE_CDB_DEFAULT_DIRECTIVE procedure, and specify the appropriate default resource allocation values.

    For example, the following procedure updates the default directive for PDBs in the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.UPDATE_CDB_DEFAULT_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        new_shares            => 2, 
        new_utilization_limit => 40);
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    
21.2.7.5 Updating the Default Directive for Maintenance Tasks in a CDB Resource Plan

You can update the AutoTask directive in a CDB resource plan using the UPDATE_CDB_AUTOTASK_DIRECTIVE procedure. The AutoTask directive applies to automatic maintenance tasks that are run in the root maintenance window.

Prerequisites

Before updating the default directive for maintenance tasks in a CDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To update the AutoTask directive for maintenance tasks in a CDB resource plan:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the UPDATE_CDB_AUTOTASK_DIRECTIVE procedure, and specify the appropriate AutoTask resource allocation values.

    For example, the following procedure updates the AutoTask directive for maintenance tasks in the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.UPDATE_CDB_AUTOTASK_DIRECTIVE(
        plan                  => 'newcdb_plan', 
        new_shares            => 2, 
        new_utilization_limit => 60);
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    
21.2.7.6 Deleting a CDB Resource Plan

You can delete a CDB resource plan using the DELETE_CDB_PLAN procedure.

The resource plan must be disabled. You might delete a CDB resource plan if the plan is no longer needed. You can enable a different CDB resource plan, or you can disable Resource Manager for the CDB.

Prerequisites

Before deleting a CDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To delete a CDB resource plan:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Run the DELETE_CDB_PLAN procedure, and specify the CDB resource plan.

    For example, the following procedure deletes the newcdb_plan CDB resource plan:

    BEGIN
      DBMS_RESOURCE_MANAGER.DELETE_CDB_PLAN(
        plan => 'newcdb_plan');
    END;
    /
    
  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    

21.2.8 Disabling a CDB Resource Plan

Disable the Resource Manager for a CDB by unsetting the RESOURCE_MANAGER_PLAN initialization parameter in the CDB root.

A CDB resource plan that specifies shares or utilization limits for PDBs is required to enable CPU management, both between PDBs and within a PDB. If a resource plan with shares or utilization limits is enabled for a PDB, and if the CDB resource plan is not specified, then the CDB resource plan is set to DEFAULT_CDB_PLAN. This setting gives equal shares to all PDBs and specifies no utilization limits. To disable CPU resource management throughout the CDB, set RESOURCE_MANAGER_PLAN to ORA$INTERNAL_CDB_PLAN.

Prerequisites

Before disabling a CDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To disable a CDB resource plan:

  1. In SQL*Plus, ensure that the current container is the root.

  2. Perform one of the following actions:

    • Use an ALTER SYSTEM statement to unset the RESOURCE_MANAGER_PLAN initialization parameter for the CDB.

      The following example unsets the RESOURCE_MANAGER_PLAN initialization parameter using an ALTER SYSTEM statement:

      ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = '';
      
    • In an initialization parameter file, unset the RESOURCE_MANAGER_PLAN initialization parameter, and restart the CDB.

      The following example unsets the RESOURCE_MANAGER_PLAN initialization parameter in an initialization parameter file:

      RESOURCE_MANAGER_PLAN = 
      

21.2.9 Viewing Information About Plans and Directives in a CDB

You can view information about CDB resource plans, CDB resource plan directives, and predefined resource plans in a CDB.

This section contains the following topics:

See Also:

Oracle Database Administrator’s Guide for information about monitoring Oracle Database Resource Manager

21.2.9.1 Viewing CDB Resource Plans

An example illustrates using the DBA_CDB_RSRC_PLANS view to display all CDB resource plans defined in the CDB.

The DEFAULT_CDB_PLAN is a default CDB plan that is supplied with Oracle Database. You can use this default plan if it meets your requirements.

To view CDB resource plans:

  1. Start SQL*Plus or SQL Developer, and log in to the CDB root.

  2. Run the following query:

    COLUMN PLAN FORMAT A30
    COLUMN STATUS FORMAT A10
    COLUMN COMMENTS FORMAT A35
     
    SELECT PLAN, STATUS, COMMENTS 
    FROM   DBA_CDB_RSRC_PLANS 
    ORDER BY PLAN;
    

    Your output looks similar to the following:

    PLAN                           STATUS     COMMENTS
    ------------------------------ ---------- -----------------------------------
    DEFAULT_CDB_PLAN                          Default CDB plan
    DEFAULT_MAINTENANCE_PLAN                  Default CDB maintenance plan
    NEWCDB_PLAN                               CDB plan for PDBs in newcdb
    ORA$INTERNAL_CDB_PLAN                     Internal CDB plan
    

Note:

Plans in the pending area have a status of PENDING. Plans in the pending area are being edited. Any plan that is not in the pending area has a NULL status.

21.2.9.2 Viewing CDB Resource Plan Directives

An example illustrates using the DBA_CDB_RSRC_PLAN_DIRECTIVES view to display all directives defined in all CDB resource plans in the CDB.

The DEFAULT_CDB_PLAN is a default CDB plan that is supplied with Oracle Database. With DEFAULT_CDB_PLAN, every PDB has 1 share and a utilization limit of 100. You can use this default plan if it meets your requirements. Note that ORA$DEFAULT_PDB_DIRECTIVE is the default directive for PDBs.

To view CDB resource plan directives:

  1. Start SQL*Plus or SQL Developer, and log in to the CDB root.

  2. Run the following query:

    COLUMN PLAN HEADING 'Plan' FORMAT A24
    COLUMN PLUGGABLE_DATABASE HEADING 'Pluggable Database' FORMAT A25
    COLUMN SHARES HEADING 'Shares' FORMAT 999
    COLUMN UTILIZATION_LIMIT HEADING 'Utilization|Limit' FORMAT 999
    COLUMN PARALLEL_SERVER_LIMIT HEADING 'Parallel|Server|Limit' FORMAT 999
     
    SELECT PLAN, 
           PLUGGABLE_DATABASE, 
           SHARES, 
           UTILIZATION_LIMIT,
           PARALLEL_SERVER_LIMIT
      FROM DBA_CDB_RSRC_PLAN_DIRECTIVES
      ORDER BY PLAN;
    

    Your output looks similar to the following:

                                                                          Parallel 
                                                              Utilization   Server 
    Plan                     Pluggable Database        Shares       Limit    Limit  
    ------------------------ ------------------------- ------ ----------- -------- 
    DEFAULT_CDB_PLAN         ORA$DEFAULT_PDB_DIRECTIVE      1         100      100
    DEFAULT_CDB_PLAN         ORA$AUTOTASK                              90      100
    DEFAULT_MAINTENANCE_PLAN ORA$AUTOTASK                              90      100
    DEFAULT_MAINTENANCE_PLAN ORA$DEFAULT_PDB_DIRECTIVE      1         100      100
    NEWCDB_PLAN              HRPDB                          1          70       70 
    NEWCDB_PLAN              SALESPDB                       3         100      100  
    NEWCDB_PLAN              ORA$DEFAULT_PDB_DIRECTIVE      1          50       50   
    NEWCDB_PLAN              ORA$AUTOTASK                   1          75       75    
    NEWCDB_PLAN              SERVICESPDB                    3         100      100   
    

    The preceding output shows the directives for the newcdb_plan created in "Creating a CDB Resource Plan for Managing PDBs: Scenario" and modified in "Modifying a CDB Resource Plan".

21.3 Managing PDB Resource Plans

You can create, enable, and modify resource plans for individual PDBs.

This section contains the following topics:

21.3.1 About PDB Resource Plans

A PDB resource plan determines how the resources for a specific PDB are allocated to consumer groups within this PDB.

A PDB resource plan is similar to a resource plan for a non-CDB. A PDB resource plan differs from a CDB resource plan, which determines the amount of resources allocated to each PDB.

In a CDB, the following restrictions apply to PDB resource plans:

  • A PDB resource plan cannot have subplans.

  • A PDB resource plan can have a maximum of eight consumer groups.

  • A PDB resource plan cannot have a multiple-level scheduling policy.

If you create a PDB using a non-CDB, and the non-CDB contains resource plans, then these resource plans might not conform to the preceding restrictions. In this case, Oracle Database automatically transforms these resource plans into equivalent PDB resource plans that meet these requirements. The original resource plans and directives are recorded in the DBA_RSRC_PLANS and DBA_RSRC_PLAN_DIRECTIVES views with the LEGACY status.

This section contains the following topics:

21.3.1.1 CDB Resource Plan Requirements When Creating PDB Resource Plans

When you create PDB resource plans, the CDB resource plan must meet certain requirements.

Create directives for a CDB resource plan by using the DBMS_RESOURCE_MANAGER.CREATE_CDB_PLAN_DIRECTIVE procedure. Create directives for a PDB resource plan using the CREATE_PLAN_DIRECTIVE procedure in the same package. When you create one or more PDB resource plans and there is no CDB resource plan, the CDB uses the DEFAULT_CDB_PLAN that is supplied with Oracle Database.

The following table describes the requirements for the CDB resource plan and the results when the requirements are not met. The parameter values described in the "CDB Resource Plan Requirements" column are for the CREATE_CDB_PLAN_DIRECTIVE procedure. The parameter values described in the "Results When Requirements Are Not Met" column are for the CREATE_PLAN_DIRECTIVE procedure.

Table 21-9 CDB Resource Plan Requirements for PDB Resource Plans

Resource CDB Resource Plan Requirements Results When Requirements Are Not Met

CPU

One of the following requirements must be met:

  • A share value must be specified for the PDB using the shares parameter.

  • A utilization limit for CPU below 100 must be specified for the PDB using the utilization_limit parameter.

These values can be set in a directive for the specific PDB or in a default directive.

The CPU allocation policy of the PDB resource plan is not enforced.

The CPU limit specified by the utilization_limit parameter in the PDB resource plan is not enforced.

Parallel execution servers

One of the following requirements must be met:

  • A share value must be specified for the PDB using the shares parameter.

  • A parallel server limit below 100 must be specified for the PDB using the parallel_server_limit parameter.

These values can be set in a directive for the specific PDB or in a default directive.

The parallel execution server allocation policy of the PDB resource plan is not enforced.

The parallel server limit specified by parallel_server_limit in the PDB resource plan is not enforced. However, you can set the PARALLEL_SERVERS_TARGET initialization parameter in a PDB to enforce the parallel limit.

21.3.1.2 PDB Resource Plan: Example

A one-to-many relationship exists between CDB resource plans and PDB resource plans.

The following figure shows an example of a CDB resource plan and a PDB resource plan.

Figure 21-4 A CDB Resource Plan and a PDB Resource Plan

Description of Figure 21-4 follows
Description of "Figure 21-4 A CDB Resource Plan and a PDB Resource Plan"

The preceding figure shows some of the directives in a PDB resource plan for the servicespdb PDB. Other PDBs in the CDB can also have PDB resource plans.

21.3.2 Creating a PDB Resource Plan

You create a PDB resource plan in the same way that you create a resource plan for a non-CDB. You use procedures in the DBMS_RESOURCE_MANAGER PL/SQL package to create the plan.

A CDB resource plan allocates a portion of the system's resources to a PDB. A PDB resource plan determines how this portion is allocated within the PDB.

The following is a summary of the steps required to create a PDB resource plan:

  1. In SQL*Plus, ensure that the current container is a PDB.
  2. Create a pending area using the CREATE_PENDING_AREA procedure.
  3. Create, modify, or delete consumer groups using the CREATE_CONSUMER_GROUP procedure.
  4. Map sessions to consumer groups using the SET_CONSUMER_GROUP_MAPPING procedure.
  5. Create the PDB resource plan using the CREATE_PLAN procedure.
  6. Create PDB resource plan directives using the CREATE_PLAN_DIRECTIVE procedure.
  7. Validate the pending area using the VALIDATE_PENDING_AREA procedure.
  8. Submit the pending area using the SUBMIT_PENDING_AREA procedure.

Ensure that the current container is a PDB and that the user has the required privileges when you complete these steps. See Oracle Database Administrator’s Guide for detailed information about completing these steps.

You also have the option of creating a simple resource plan that is adequate for many situations using the CREATE_SIMPLE_PLAN procedure. See Oracle Database Administrator’s Guide for information about creating a simple resource plan.

Note:

Some restrictions apply to PDB resource plans. See "About PDB Resource Plans" for information.

21.3.3 Enabling a PDB Resource Plan

Enable a PDB resource plan by setting the RESOURCE_MANAGER_PLAN initialization parameter to the plan with an ALTER SYSTEM statement when the current container is the PDB.

If no plan is specified with this parameter, then no PDB resource plan is enabled for the PDB.

Prerequisites

Before enabling a PDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To enable a PDB resource plan:

  1. In SQL*Plus, ensure that the current container is a PDB.

  2. Use an ALTER SYSTEM statement to set the RESOURCE_MANAGER_PLAN initialization parameter to the PDB resource plan.

You can also schedule a PDB resource plan change with Oracle Scheduler.

Example 21-5 Enabling a PDB Resource Plan

The following example sets the PDB resource plan to salespdb_plan.

ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = 'salespdb_plan';

See Also:

21.3.4 Modifying a PDB Resource Plan

You can use the DBMS_RESOURCE_MANAGER package to modify a PDB resource plan in the same way you would modify the resource plan for a non-CDB.

Prerequisites

Before modifying a PDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To modify a PDB resource plan:

  1. In SQL*Plus, ensure that the current container is a PDB.

  2. Create a pending area:

    exec DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
    
  3. Modify the PDB resource plan by completing one or more of the following tasks:

    • Update a consumer group using the UPDATE_CONSUMER_GROUP procedure.

    • Delete a consumer group using the DELETE_CONSUMER_GROUP procedure.

    • Update a resource plan using the UPDATE_PLAN procedure.

    • Delete a resource plan using the DELETE_PLAN procedure.

    • Update a resource plan directive using the UPDATE_PLAN_DIRECTIVE procedure.

    • Delete a resource plan directive using the DELETE_PLAN_DIRECTIVE procedure.

  4. Validate the pending area:

    exec DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
    
  5. Submit the pending area:

    exec DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
    

See Also:

21.3.5 Disabling a PDB Resource Plan

You disable a PDB resource plan by unsetting the RESOURCE_MANAGER_PLAN initialization parameter in the PDB.

Prerequisites

Before disabling a PDB resource plan, complete the prerequisites described in "Overview of Oracle Resource Manager in a Multitenant Environment".

To disable a PDB resource plan:

  1. In SQL*Plus, ensure that the current container is a PDB.

  2. Use an ALTER SYSTEM statement to unset the RESOURCE_MANAGER_PLAN initialization parameter for the PDB.

Example 21-6 Disabling a PDB Resource Plan

The following example disables the PDB resource plan.

ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = '';

21.4 Monitoring PDBs Managed by Oracle Database Resource Manager

A set of dynamic performance views enables you to monitor the results of your Oracle Database Resource Manager settings for PDBs.

This section contains the following topics:

21.4.1 About Resource Manager Views for PDBs

You can monitor the results of your Oracle Database Resource Manager settings for PDBs using views.

The following views are available:

  • V$RSRCPDBMETRIC

    The V$RSRCPDBMETRIC view provides current statistics on resource consumption for PDBs, including CPU usage, parallel execution, I/O generated, and memory usage.

  • V$RSRCPDBMETRIC_HISTORY

    The columns in the V$RSRCPDBMETRIC_HISTORY view are the same as the columns in the V$RSRCPDBMETRIC view. The only difference between these views is that the V$RSRCPDBMETRIC view contains metrics for the past one minute only, whereas the V$RSRCPDBMETRIC_HISTORY view contains metrics for the last 60 minutes.

  • V$RSRC_PDB

    The V$RSRC_PDB view provides cumulative statistics. The statistics are accumulated since the time that the CDB resource plan was set.

  • DBA_HIST_RSRC_PDB_METRIC

    This view contains the historical statistics of V$RSRCPDBMETRIC_HISTORY, taken using Automatic Workload Repository (AWR) snapshots.

Note:

The V$RSRCPDBMETRIC and V$RSRCPDBMETRIC_HISTORY views record statistics for resources that are not currently being managed by Resource Manager when the STATISTICS_LEVEL initialization parameter is set to ALL or TYPICAL.

See Also:

21.4.2 Monitoring CPU Usage for PDBs

The V$RSRCPDBMETRIC view enables you to track CPU metrics in milliseconds, in terms of number of sessions, or in terms of utilization for the past one minute.

The view provides real-time metrics for each PDB and is very useful in scenarios where you are running workloads and want to continuously monitor CPU resource utilization.

The active CDB resource plan manages CPU usage for a PDB. Use this view to compare the maximum and average CPU utilization for PDBs with other PDB settings such as the following:

  • CPU time used

  • Time waiting for CPU

  • Average number of sessions that are consuming CPU

  • Number of sessions that are waiting for CPU allocation

For example, you can view the amount of CPU resources a PDB used and how long it waited for resource allocation. Alternatively, you can view how many sessions from each PDB are executed against the total number of active sessions.

Tracking CPU Consumption in Terms of CPU Utilization for PDBs

To track CPU consumption in terms of CPU utilization, query the CPU_UTILIZATION_LIMIT and AVG_CPU_UTILIZATION columns. AVG_CPU_UTILIZATION lists the average percentage of the server's CPU that is consumed by a PDB. CPU_UTILIZATION_LIMIT represents the maximum percentage of the server's CPU that a PDB can use. This limit is set using the UTILIZATION_LIMIT directive attribute.

The following query displays this information by showing the container ID (CON_ID) and name of each PDB:

COLUMN PDB_NAME FORMAT A10

SELECT r.CON_ID, 
       p.PDB_NAME, 
       r.CPU_UTILIZATION_LIMIT, 
       r.AVG_CPU_UTILIZATION 
FROM   V$RSRCPDBMETRIC r, 
       CDB_PDBS p
WHERE r.CON_ID = p.CON_ID;

Tracking CPU Consumption and Throttling for PDBs

Use the CPU_CONSUMED_TIME and CPU_TIME_WAIT columns to track CPU consumption and throttling in milliseconds for each PDB. The column NUM_CPUS represents the number of CPUs that Resource Manager is managing.

The following query displays this information by showing the container ID (CON_ID) and name of each PDB:

COLUMN PDB_NAME FORMAT A10

SELECT r.CON_ID, 
       p.PDB_NAME, 
       r.CPU_CONSUMED_TIME, 
       r.CPU_WAIT_TIME, 
       r.NUM_CPUS 
FROM   V$RSRCPDBMETRIC r, 
       CDB_PDBS p
WHERE r.CON_ID = p.CON_ID;

Tracking CPU Consumption and Throttling in Terms of Number of Sessions for PDBs

To track the CPU consumption and throttling in terms of number of sessions, use the RUNNING_SESSIONS_LIMIT, AVG_RUNNING_SESSIONS, and AVG_WAITING_SESSIONS columns. RUNNING_SESSIONS_LIMIT lists the maximum number of sessions from a particular PDB that can be running at any time. This limit is defined by the UTILIZATION_LIMIT directive attribute that you set for the PDB. AVG_RUNNING_SESSIONS lists the average number of sessions that are consuming CPU, and AVG_WAITING_SESSIONS lists the average number of sessions that are waiting for CPU.

The following query displays this information by showing the container ID (CON_ID) and name of each PDB:

COLUMN PDB_NAME FORMAT A10

SELECT r.CON_ID, 
       p.PDB_NAME, 
       r.RUNNING_SESSIONS_LIMIT, 
       r.AVG_RUNNING_SESSIONS, 
       r.AVG_WAITING_SESSIONS 
FROM   V$RSRCPDBMETRIC r, 
       CDB_PDBS p
WHERE r.CON_ID = p.CON_ID;

21.4.3 Monitoring Parallel Execution for PDBs

The V$RSRCPDBMETRIC view enables you to track parallel statements and parallel server use for PDBs.

Parallel execution servers for a PDB are managed with the active CDB resource plan of the PDB's CDB. To track parallel statements and parallel server use for PDBs, use the AVG_ACTIVE_PARALLEL_STMTS, AVG_QUEUED_PARALLEL_STMTS, AVG_ACTIVE_PARALLEL_SERVERS, AVG_QUEUED_PARALLEL_SERVERS, and PARALLEL_SERVERS_LIMIT columns.

AVG_ACTIVE_PARALLEL_STMTS and AVG_ACTIVE_PARALLEL_SERVERS list the average number of parallel statements running and the average number of parallel servers used by the parallel statements. AVG_QUEUED_PARALLEL_STMTS and AVG_QUEUED_PARALLEL_SERVERS list the average number of parallel statements queued and average number of parallel servers that were requested by queued parallel statements. PARALLEL_SERVERS_LIMIT lists the number of parallel servers allowed to be used by the PDB.

The following query displays this information by showing the container ID (CON_ID) and name of each PDB:

COLUMN PDB_NAME FORMAT A10

SELECT r.CON_ID, p.PDB_NAME, r.AVG_ACTIVE_PARALLEL_STMTS, r.AVG_QUEUED_PARALLEL_STMTS, 
   r.AVG_ACTIVE_PARALLEL_SERVERS, r.AVG_QUEUED_PARALLEL_SERVERS, r.PARALLEL_SERVERS_LIMIT
   FROM V$RSRCPDBMETRIC r, CDB_PDBS p
   WHERE r.CON_ID = p.CON_ID;

21.4.4 Monitoring the I/O Generated by PDBs

The V$RSRCPDBMETRIC view enables you to track the amount of I/O generated by PDBs.

I/O is limited for a PDB by setting the MAX_IOPS initialization parameter or the MAX_MBPS initialization parameter in the PDB. Use this view to compare the I/O generated by PDBs in terms of the number of operations each second and the number of megabytes each second.

Tracking the Number of I/O Operations Generated Each Second by PDBs

To track the I/O operations generated each second by PDBs during the previous minute, use the IOPS column.

The following query displays this information by showing the container ID (CON_ID) and name of each PDB:

COLUMN PDB_NAME FORMAT A10

SELECT r.CON_ID, p.PDB_NAME, r.IOPS 
   FROM V$RSRCPDBMETRIC r, CDB_PDBS p
   WHERE r.CON_ID = p.CON_ID;

Tracking the Number Megabytes Generated for I/O Operations Each Second by PDBs

To track number of megabytes generated for I/O operations each second by PDBs during the previous minute, use the IOMBPS column.

The following query displays this information by showing the container ID (CON_ID) and name of each PDB:

COLUMN PDB_NAME FORMAT A10

SELECT r.CON_ID, p.PDB_NAME, r.IOMBPS 
   FROM V$RSRCPDBMETRIC r, CDB_PDBS p
   WHERE r.CON_ID = p.CON_ID;

21.4.5 Monitoring Memory Usage for PDBs

The V$RSRCPDBMETRIC view enables you to track the amount memory used by PDBs.

Use this view to track the amount of SGA, PGA, buffer cache, and shared pool memory currently used by PDBs.

To track the current memory usage, in bytes, for specific PDBs, use the SGA_BYTES, PGA_BYTES, BUFFER_CACHE_BYTES, and SHARED_POOL_BYTES columns.

The following query displays this information by showing the container ID (CON_ID) and name of each PDB:

COLUMN PDB_NAME FORMAT A10

SELECT r.CON_ID, p.PDB_NAME, r.SGA_BYTES, r.PGA_BYTES, r.BUFFER_CACHE_BYTES, r.SHARED_POOL_BYTES
   FROM V$RSRCPDBMETRIC r, CDB_PDBS p
   WHERE r.CON_ID = p.CON_ID;