Starting with Oracle Database 21c, you can configure Database Resident Connection Pooling (DRCP) from the CDB to individual PDBs for improved PDB tenancy management.
In previous releases, the DRCP pool was used by the entire container database (CDB). With per-PDB pools, you can now configure, manage, and monitor pools on individual pluggable databases (PDBs), on the basis of tenancy. This feature also provides the ability to specify Connection Class and Purity support in connect strings for DRCP. With this change, you can leverage DRCP without application code change. This feature eases the management of DRCP pool by changing the granularity of the DRCP pool from the entire CDB to a per-PDB DRCP pool. This change enables tenant administrators to configure and manage independent tenant-specific DRCP pools. Additionally this feature enables applications to leverage some of the DRCP benefits with making any application changes.