How to check for existence of nested JSONB property key?

Hello all,

We have a table with material properties stored as JSONB objects, as the
available properties differ wildly between different kinds of materials.
It's semi-structured data.
I am in a situation where I want to filter our materials based on the
existence of a certain property, regardless its value.

A query for such a property with a specific value is easy, that even
uses a GIST index we defined on that table.
For example:
select obj -> 'top' -> 'next' -> 'key' as key_value
  from (values('{"top":{"next":{"key":3}}}'::jsonb)) x(obj)
 where obj @> '{"top":{"next":{"key":3}}}';

 key_value
-----------
 3
(1 row)

I'd like to do the same for an "incomplete" search object, where the
"value" is an object instead of a literal:

select obj -> 'top' -> 'next' -> 'key' as key_value
   from (values('{"top":{"next":{"key":3}}}'::jsonb)) x(obj)
 where obj @> '{"top":{"next":"key"}}';

 key_value
-----------
(0 rows)

I was hoping for the same result as above. Apparently the jsonb contains
operator requires an exact match?

Is there an approach that can do this, preferably making use of the GIST
index? Mind that the nesting depth of the search object can vary, like
the material properties vary, I'm looking for a generic approach here.

We're on PG 11(.9), so the enhancements made to JSONB operations in PG12
are not (yet) available to us. This is a 3TB database w/o replica's, so
upgrading it is a little scary and requires a maintenance window that
would be sufficient to restore a backup in case things go wrong.

Regards,
Alban Hertroys.

Alban Hertroys
D: 8776 |M: |T: +31 (0)53 4888 888 | E: alban(dot)hertroys(at)apollotyres(dot)com
Apollo Vredestein B.V.| Ir. E.L.C. Schiffstraat 370, 7547 RD Enschede, The Netherlands
Chamber of Commerce number: 34223268


The information contained in this e-mail is intended solely for the use of the individual or entity to whom it is addressed. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution or action in relation to the contents of this information is strictly prohibited and may be unlawful and request you to delete this message and any attachments and advise the sender by return e-mail. The confidentiality of this message is not warranted. Apollo Vredestein and its subsidiaries rule out any and every liability resulting from this or any other electronic transmission.
Please consider the environment before printing this e-mail

CIN: L25111KL1972PLC002449

Registered Office: Apollo Tyres Ltd, 3rd Floor, Areekal Mansion, Panampilly Nagar, Kochi 682036, India

Disclaimer:

The information contained in this e-mail is intended solely for the use of the individual or entity to whom it is addressed. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution or action in relation to the contents of this information is strictly prohibited and may be unlawful and request you to delete this message and any attachments and advise the sender by return e-mail. The confidentiality of this message is not warranted. Apollo Tyres and its subsidiaries rule out any and every liability resulting from this or any other electronic transmiss