Description of the Issue
When new users are learning how to manually register schemas, it is very easy to forget the ::regclass cast and pass the table name as a plain string:
SELECT graph.add_table('public.users', 'id');
This results in the following PostgreSQL error:
ERROR: function graph.add_table(unknown, unknown) does not exist
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
Why this is a problem
Because the error states that the function does not exist (rather than saying "invalid table name" or "missing OID cast"), it is highly confusing for users who aren't deeply familiar with Postgres function overloading. They often assume they installed the extension incorrectly or are calling the wrong function name.
Currently, there is no entry for this common error in docs/user_guide/troubleshooting.mdx.
Proposed Solution
Add a dedicated section at the very top of troubleshooting.mdx addressing the Function Does Not Exist (Type Cast Error) symptom, explaining that table parameters require the ::regclass cast, and providing the corrected SQL example.
I am happy to submit a Pull Request to add this if the maintainers agree!
Description of the Issue
When new users are learning how to manually register schemas, it is very easy to forget the
::regclasscast and pass the table name as a plain string: