Out-of-Place Upgrade:

Benefits:

• Reduced downtime: You can run the new database in parallel, minimizing downtime.
• Testing: You can thoroughly test the upgrade without affecting the existing database.
• Backout plan: Easier to revert to the previous version if issues arise.
• Incorporate and execute widely accepted industry best practices within the target system.
• An opportune time to perform an operating system upgrade on the target system.

Considerations:

• Requires additional hardware and storage.
• May require changes to application connection strings.

In-Place Upgrade:

Benefits:

• No need for additional hardware.

Considerations:

• Minimal testing opportunities.
• Longer downtime.
• Less flexibility to revert to the previous version.
• Increased complexity resulting from prior installations or configurations that did not adhere to best practices.
• Cannot upgrade and convert to multitennancy.

The most challenging post-upgrade tasks typically include:

• Verifying data integrity and object counts.
• Ensuring compliance with licensed options.
• Migrating deprecated features like DBMS_JOBS to DBMS_SCHEDULER_JOBS.
• Ensuring user password hashes are in at least 12c format.
• Rectifying any invalid objects.
• Optimizing database statistics and performance.
• Testing application compatibility.
• Updating backup and recovery strategies.
• Performance tuning.
• Documenting changes.

Yes, you can convert and upgrade a non-multitenant (non-CDB) database to a multitenant (CDB) architecture in Oracle Database 19c. This process involves creating a new pluggable database (PDB) in a CDB and migrating your data into it. The steps include creating a CDB, plugging in a PDB, and migrating data into the PDB. All automated steps are performed following Oracle recommended best practices.

The performance impact of the multitenant architecture in Oracle Database 19c depends on various factors, including your specific use case, database design, and resource allocation. Some considerations ORMIT-DB takes into account:

• Resource Sharing: Multitenant architecture allows for better resource sharing, as multiple pluggable databases (PDBs) share a common container database (CDB). This can be more efficient in terms of resource utilization.
• Isolation: PDBs are isolated, and resource management can be controlled at both the CDB and PDB levels. This isolation can prevent resource contention among different applications or tenants, potentially improving performance.
• Consolidation: Multitenant architecture is particularly beneficial for database consolidation. It allows multiple applications or tenants to coexist within a single CDB, which can lead to more efficient resource usage and reduced hardware costs.
• Simplified Management: Centralized management of PDBs simplifies tasks such as backup, recovery, and patching. This can save administrative time and improve database management efficiency.
• Pluggable Database Performance: The performance of each PDB can vary based on its workload, configuration, and resource allocation. You have the flexibility to allocate resources according to the specific needs of each PDB.
• Testing and Tuning: The migration to a multitenant architecture may require careful testing and tuning to achieve optimal performance. Factors like shared resources, CPU, memory, and I/O must be managed effectively.

Oracle Database 19c's multitenant architecture holds the promise of enhanced performance by streamlining resource utilization and administration. Nevertheless, the actual performance enhancements are contingent upon the particulars of your implementation, the workload, and the optimization endeavors. ORMIT-DB thoughtfully considers all these factors. Conducting thorough pre-migration performance analysis, meticulous planning, as well as ongoing monitoring and tuning, are vital to fully realize the performance advantages offered by the multitenant architecture.