1. Cloud Administration Guide
  2. Maintaining and Customizing Databases
  3. PDB Instance Resize

33 PDB Instance Resize

This chapter covers the PDB Instance Resize feature, and contains the following sections:

Introduction

You can resize an OEM DBaaS Pluggable Database instance by initiating a resize operation to a workload size defined in the corresponding service template. This resize operation ensures sufficient availability and effective utilization of resources.

Table 33-1 Impacted Pluggable Database Initialization Parameter Values

Parameter Description

Session

Pluggable database sessions parameter is updated as per the new workload size.

Storage

Pluggable Database MAX_PDB_STORAGE parameter is impacted if Pluggable Database Storage -> Maximum Size is set to Specified by the workload size selected at request time in the corresponding service template.

CPU

If DB version < 12.2, CPU constraint is enforced using PDB Resource Plan Directive utilization_limit, if Enable Resource Manager for CPU is selected in Pluggable Database Pool.

if DB version >= 12.2, in addition to Resource Plan Directive utilization_limit, pluggable database cpu_count parameter is set as per the new workload size.

Memory

If DB version < 12.2, memory parameter is not enforced.

If DB version >= 12.2, Pluggable database SGA_TARGET and PGA_AGGREGATE_TARGET parameters are updated as per the new workload memory value.
  • SGA_TARGET => 75 percent of the total memory specified in the new workload.
  • PGA_AGGREGATE_TARGET => 25 percent of the total memory specified in the new workload.

Prerequisites

The prerequisites to perform a resize operation are:

  • NONCDB_COMPATIBLE parameter must be set to false in the CDB for enforcing pluggable database memory constraints.

  • For the CDB, memory_target parameter value must be zero.

  • CDB sga_target must be higher than pluggable database sga_target. (PDB sga_target value is set to 75 percent of the total memory specified in the new workload.)

  • CDB pga_aggregate_limit must be more than twice the PDB pga_aggregate_target.

  • CDB pga_aggregate_target must be higher than pluggable database pga_aggregate_target. (Resize operation updates pluggable database pga_aggregate_target value as 25 percent of total memory specified in the new workload size.)

An Enterprise Manager Administrator with EM_SSA_ADMINISTRATOR or EM_SSA_USER role can initiate the PDB Instance resize operation.

PDB Resize: Self-service Portal

You can use the Resize button to initiate a resize operation. However, the Resize button is enabled only if the service template for PDB has more than one workload.

Figure 33-1 PDB Resize


PDB Resize

After the Resize button is clicked, you can select a size from the drop-down list.

Figure 33-2 Resize Options


Resize Options

PDB Resize: EMCLI Command

This section provides details on resizing PDB instance using EMCLI command:

$ emcli db_cloud_maintenance –resizeService -pdbName=”<pdb target name>” -workloadName=”<workload name to be used for resizing>”

Limitations

The limitations for performing a resize operation are:

  • If the PDB actual storage consumption is greater than the storage value in the new workload, PDB scale down operation is not possible.

  • If sufficient resources are not available on the target host for resizing PDB, the PDB Relocation feature must be used. For more information, refer PDB Relocation.