Re: Error “cache lookup failed for function”

Am 20.02.20 21:41 schrieb(en) Adrian Klaver:
> It would be nice to know what:
[snip]
> represented in:

Dropping and re-creating the function is actually the last operation in the script. The function is /very/ simple (just a wrapper to hide all internals from "agent" clients):

---8<--------------------------------------------------------------------
DROP FUNCTION public.get_result2(mytaskid bigint, OUT data bytea, OUT metadata jsonb, OUT errortext text, OUT vanished boolean);
CREATE FUNCTION public.get_result2(mytaskid bigint, OUT data bytea, OUT metadata jsonb, OUT errortext text, OUT vanished boolean) RETURNS record
LANGUAGE plpgsql STABLE SECURITY DEFINER
SET search_path TO 'public', 'pg_temp'
AS $$
BEGIN
SELECT r.data, r.metadata, r.errortext FROM results r INNER JOIN tasks USING(resultid) WHERE taskid = mytaskid LIMIT 1 INTO data, metadata, errortext;
SELECT COUNT(*) = 0 FROM tasks WHERE taskid = mytaskid INTO vanished;
END;
$$;
ALTER FUNCTION public.get_result2(mytaskid bigint, OUT data bytea, OUT metadata jsonb, OUT errortext text, OUT vanished boolean) OWNER TO manager;
REVOKE ALL ON FUNCTION public.get_result2(mytaskid bigint, OUT data bytea, OUT metadata jsonb, OUT errortext text, OUT vanished boolean) FROM PUBLIC;
GRANT ALL ON FUNCTION public.get_result2(mytaskid bigint, OUT data bytea, OUT metadata jsonb, OUT errortext text, OUT vanished boolean) TO "agent";
COMMIT;
---8<--------------------------------------------------------------------

> The Postgres logs during and after restart might provide some info.
>
> Also the errors thrown when accessing the other function.

I attach the (slightly stripped down; I don't want to post ~100k…) log, starting with the very first error at 13:39:59.302 UTC. Prior to that line are *no* errors. I added a few [comments].

At 13:39:59.484 the error message changes, referring to an ancient function “retrieve_single_result()” which (according to the person who wrote the “agent” client) is *not* called. The clients try periodically poll “get_result2()”.

At 13:42:00 the “systemctl restart” has been initiated. At 13:42:02 the database has been stopped and is restarted immediately, revealing one misconfigured client (should be harmless), but the cache lookup error persists.

Thanks in advance for your help,
Albrecht.