Privileges granted on dblink extension function do not survive database dump and restore

I've implemented a very large materialized view to speed up certain search queries. I need to give users the ability to start a concurrent refresh on demand, without waiting around an hour for it to complete, so I've been looking at using the dblink extension. Specifically, giving a web usr the privilege to execute dblink functions like the asynchronous 'dblink_send_query' function to refresh the materialized view.

The problem I have,  is that while I can grant execute on dblink functions to my web_usr in an existing database, if I dump and restore that database the execute privileges disappear. Is this expected behavior? Or a bug?

I've used the commands 'CREATE EXTENSION dblink WITH SCHEMA public;' and

'GRANT EXECUTE ON FUNCTION public.dblink_send_query(text, text) TO web_usr;' to set this up,

and 'SELECT proacl FROM pg_proc WHERE proname='dblink_send_query';' to verify the user privileges before and after the dump and restore.

Bug or not, are there other methods out there for keeping materialized views update to date I could explore?

And ideas are welcome, this has been driving me crazy!

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