Have you ever had cases of upgrading the database product version? How did you prepare and what problems arose?

Yes, there was experience with upgrading the database version. The preparation included:

• Testing the new version on a test environment with a copy of data to identify potential incompatibilities and performance issues.
• Checking changes in SQL syntax, function behavior, and new configuration parameters.
• Creating a rollback plan in case of failure.
• Updating drivers and client libraries if necessary.

Problems encountered:

• Changes in index behavior or query planner leading to performance degradation.
• Incompatibility of old backups with the new version.
• The need for data migration or format conversion.

It is important to carefully plan and conduct the upgrade in a controlled environment to minimize risks.