Cdb

Oracle Multitenant was introduced in 12c and is now the default deployment model. Despite broad adoption, the internal mechanics of how CDBs and PDBs share and isolate resources are frequently misunderstood. This article is for architects designing multitenant deployments who need to reason about performance isolation, resource governance, and operational boundaries. CDB vs Non-CDB: The Core Difference In a non-CDB, the database owns the entire Oracle instance. In a CDB: ...

This article is a practical tuning script library. Each script targets a specific, common real-world performance scenario — not abstract examples, but the situations that actually appear at 2am during an incident. Scripts are annotated with where they run, what the output means, and what action to take. Reference Environment Single Instance: Host: ora19c01.prod.example.com DB Name: ORCL19C Oracle: 19.22.0.0 (Oracle Linux 8) Memory: 256 GB RAM, 32 vCPU Storage: Local NVMe (non-Exadata) CDB Environment: Host: cdb01.prod.example.com (Exadata VM) CDB Name: PRODCDB PDBs: PDB_OLTP, PDB_DWH, PDB_REPORTING Oracle: 19.22.0.0 Memory: 512 GB RAM (Exadata X8M-2 node) Scenario 1: “The Database Was Slow from 09:00 to 09:30 This Morning” Situation: Application team reports intermittent slowness on cdb01. You need to identify what happened between 09:00 and 09:30. ...