Oracle Documentation and Dangers of the AI

Earlier today I presented a webinar for NYOUG on one of my favorite topics - building SQL queries on the fly (btw, if anybody interested - slides and video will recording will be available a bit later):
https://nyoug.org/event/dynamic-mechanisms-of-query-building/

And during the presentation a recent in-house story came to my mind - based on my own remark. I said something like: "If you are using advanced functionality, you really need to know the features you are planning to use - not just copy/paste code snippets from ChatGPT or any other preferred AI tool" 

The statement above is perfectly true - and I even got an illustration (kind-of) for it based on the true "mini-scare" that happened in our office.

Here is the story. For many years a lot of my friends were laughing at me when I was telling that one of the biggest (government) projects that is being supported by Dulcian is still on Oracle 11.2.0.4. Finally this year our partners responsible for the administering the system got it to 19c. All is good - but for some internal reasons the production environment is still running with  "compatible=11.2.0.4.0"!

Of course, for us (i.e. development shop) it is a major restriction - and I've been very vocal about finally moving that parameter to "19.0.0". Couple of weeks ago in the internal communication I've got a bit panicky email from one of my colleagues: "Depending on how I ask an AI get different answers whether downgrade is possible! Help!" + a couple of screenshots:

#1 Gemini (Google)

#2 ChatGPT

As you can see, one platform says clear "NO" and the other one says that it is clearly possible, but there may be some impact that needs to be evaluated.

After hours of research I can say the following - Gemini is closer to the real answer than ChatGPT. Even though there are empirical evidences that it is possible in some circumstances (different combinations of versions) to lower compatibility parameter, it is strongly not recommended. So much not recommended that in 19c docs it is explicitly written that you cannot go back to 11.2.0.4 at all:

Summary: be VERY careful when you use various AI tools - it could be a good starting point, but without going to the core references you cannot be sure that you are getting real answers. Buyers, beware! :)