Re: Are we sufficiently clear that jsonb containment is nested?

On Thu, Oct 29, 2015 at 1:16 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I think the existing text is largely my fault, so I'll do something with
> this.

Good. Thanks.

>> I still think it would be a good idea to go back to 9.4. I have reason
>> to believe that people are getting confused on this point.
>
> You didn't present evidence backing that up, but I agree that
> clarification is a sufficient reason to back-patch doc changes.

It's difficult to provide evidence for the existence of a perception
among users when it's a perception that a quasi-reasonable limitation
exists. The fact that jsonb_path_ops can make indexing complex jsonb
documents practical is fairly novel, so I'm not surprised that users
seem to imagine that containment does not work in a nested fashion.
"Existence" (the ? operator) actually has this limitation.

-- 
Peter Geoghegan