In Oracle 12c, Oracle Resource Manager has been enhanced to support Multitenant by allowing to limit and prioritize CPU resources among competing PDBs.
Currently, it is not possible to prioritize memory resources, only CPU resources can be defined using Oracle Resource Manager.
My idea is to enhance Oracle Resource Manager to also limit and prioritize memory resources among competing PDBs.
Update: PDB-level memory controls are now provided with Oracle Database 12c Release 2
PDB-Level Memory Controls
In a CDB, PDBs may contend for SGA or PGA memory. Several initialization parameters can control the memory usage of a PDB, either guaranteeing memory or limiting memory. When you set the following initialization parameters with the PDB as the current container, the parameters control the memory usage of the current PDB.
Examples of important parameters include:
SGA_MIN_SIZE sets the minimum guaranteed SGA size of the PDB.SGA_TARGET specifies the maximum SGA that the PDB can use at any time.PGA_AGGREGATE_LIMIT sets the maximum PGA that the PDB can use at any time.
For more information please refer to: Overview of Oracle Resource Manager in a CDB