Compatibility and Interoperability Between Oracle Database Releases

Learn how to understand and avoid compatibility and interoperability issues that can occur because of differences in Oracle Database releases.

Oracle Database releases can have differences that can result in compatibility and interoperability issues. These differences can affect both general database administration and existing applications.

• About Oracle Database Release Numbers
  Oracle Database releases are categorized by five numeric segments that indicate release information.
• Convention for Referring to Release Numbers in Upgrade Topics
  Review to understand how statements in upgrade topics apply to releases.
• What Is Oracle Database Compatibility?
  Before you upgrade, review compatibility between your earlier release Oracle Database and the new Oracle AI Database release as part of your upgrade plan.
• Updating the Database Compatibility Level
  To use some new features in a release, you must update the COMPATIBLE parameter to the release update that contains the new feature.
• Dynamic Update of COMPATIBLE Setting for Oracle AI Database
  Starting with Oracle AI Database 26ai, you can change the COMPATIBLE setting for all sessions in the current Oracle AI Database instance without having to restart the instance.
• What Is Interoperability for Oracle Database Upgrades?
  In the context of upgrading Oracle Database to Oracle AI Database, interoperability is the ability of different database releases to communicate and work in a distributed environment.
• About Invalid Schema Objects and Database Upgrades
  Run utlrp.sql to validate invalid objects as part of your upgrade test plan.

Dynamic Update of COMPATIBLE Setting for Oracle AI Database

Starting with Oracle AI Database 26ai, you can change the COMPATIBLE setting for all sessions in the current Oracle AI Database instance without having to restart the instance.

If you want to enable new functionality in Oracle AI Database that is available in a higher release update (RU), you can now change the COMPATIBLE setting for in-memory processes, and not have to restart database instances. This option is only available in releases starting with Oracle AI Database 26ai that can be updated to a new RU. To use the new functionality available in an RU, update the COMPATIBLE setting to the value major-release.release-update.

The following restrictions for this feature apply:

• This option is available only on Oracle AI Database 26ai databases, and only when moving to a higher RU within Oracle AI Database 26ai.

  Changing the in-memory COMPATIBLE setting without requiring instance restarts can only be performed with ALTER DATABASE SET DOWNGRADE COMPATIBILITY. It cannot be done with ALTER SYSTEM.

• If there are primary and multiple standbys, then you must issue the command on standbys first, and then on the primary.
• If the command is interrupted, then you can issue the change COMPATIBLE command again.
• If the command is issued on the primary database, then it must be issued in an instance where CDB$ROOT is open.
• If multiple sessions issue the same command concurrently, then only one of them will succeed.

Note:

To use the new functionality available in an RU, update the COMPATIBLE setting to the value major-release.release-update.