Here is a list of things to check and carry out while preparing for Oracle Database 23ai.

These tasks are not mandatory, but I recommend them based on my experience. It increases your chance of upgrading with success.

Weeks Before

Platform Certification

Ensure that the new release supports your operating system. When available, you can check it in the installation guides. However, you can find the most up-to-date information in the Certifications tab in My Oracle Support.

Clients

Check the clients connecting to the database and ensure their client driver version is compatible with Oracle Database 23ai. The client/server interoperability matrix gives you an overview of which clients work with which servers.

Optionally, monitor the database over time to generate a list of clients connecting.

AutoUpgrade

Get the latest version of AutoUpgrade from My Oracle Support. I recommend that you always use the latest version. AutoUpgrade is fully backward compatible, so any newer version can upgrade older releases of Oracle Database.

Upgrade Readiness

Run AutoUpgrade in analyze mode to determine the upgrade readiness of your Oracle Database. Check the summary report for findings with no fixups. Such findings must be dealt with manually.

You can run the analysis even before you install the new Oracle home. Simply specify target_version=23 in your AutoUpgrade config file, and AutoUpgrade knows which checks to run.

Dictionary Check

Check the dictionary on your most important databases. You can run a dictionary check together with an AutoUpgrade analysis. In your config file:

upg1.run_dictionary_health=full

Or, you can run it separately using DBMS_DICTIONARY_CHECK.

Behavior Changes

Review the upgrade guide to find information about deprecated and desupported features, plus any behavior changes.

Grid Infrastructure

If Grid Infrastructure manages your database either in RAC or Oracle Restart configuration, you should upgrade it as well. If you can tolerate an additional maintenance window, I’d recommend upgrading Grid Infrastructure in advance.

Days Before

Statistics

Gather dictionary and fixed objects statistics:

begin
   dbms_stats.gather_fixed_objects_stats;
   dbms_stats.gather_schema_stats('SYS');
   dbms_stats.gather_schema_stats('SYSTEM')
end;

I prefer gathering schema stats rather than dictionary stats. I’ve seen a few edge cases solved by schema stats, and generally, current stats on SYS and SYSTEM are sufficient.

Gather statistics no earlier than seven days before the upgrade. If AutoUpgrade determines your statistics are older than that, it will gather them as part of the upgrade. This extends down time unnecessarily.

If you’re curious, you can find details about the importance of fixed objects statistics in a blog post by Maria Colgan.

Install Oracle Home

Install an Oracle Database 23ai Oracle home. In release 23ai, the Oracle homes that you download are already patched with the latest Release Update.

If you have additional patches to apply, do so now. You should have all patches in place before you start the upgrade.

On the Day of Upgrade

Backup

If time allows, run a level 0 backup. If not, you have to settle with a level 1.

Scheduler

Normally, it is not necessary to disable the scheduler. But in some situations, it can be beneficial.

That’s It

You are now ready to start the journey to Oracle Database 23ai and the many exciting new features.

Happy upgrading!