Aurora PostgreSQL minor version upgrade ongoing for several days

It is not typical for an Aurora PostgreSQL minor version upgrade to take several days to complete. Both minor and major version upgrades for Aurora PostgreSQL typically involve brief outages, and are generally designed to be completed within a short timeframe.

If your upgrade has been "ongoing" for several days, this likely indicates an issue with the upgrade process. Minor version upgrades, while less disruptive than major upgrades, should not take this long to complete.

For a normal minor version upgrade, the duration can vary depending on the size of your cluster and the specific changes in the new version, but it should typically complete within minutes to hours, not days.

I recommend contacting AWS Support for assistance with this issue. They can provide specific insights into your cluster's status and help resolve any problems with the upgrade process. For future upgrades, it's strongly recommended to perform them during your maintenance window or during periods of low utilization to minimize potential impact.
Sources
Our DB Cluster is Down during Minor Version Upgrade | AWS re:Post
Upgrading Amazon Aurora PostgreSQL DB clusters - Amazon Aurora