我想知道一个函数是内置的还是用户定义的。我试着写下面的查询，但是没有任何东西告诉我是两者之一还是两者之一。我在pgadmin中搜索了一个函数后，从postgres日志中获得了这个查询。结果列表也显示了像dblink这样的函数。

SELECT obj_type, function_owner,obj_name,
            pg_catalog.REPLACE(obj_path, '/'||sn.schema_name||'/', '/'||CASE sn.schema_name
            WHEN 'pg_catalog' THEN 'PostgreSQL Catalog (pg_catalog)'
            WHEN 'pgagent' THEN 'pgAgent Job Scheduler (pgagent)'
            WHEN 'information_schema' THEN 'ANSI (information_schema)'
            ELSE sn.schema_name
            END||'/') AS obj_path,
            schema_name, show_node, other_info,
            CASE
                WHEN sn.schema_name IN ('pg_catalog', 'pgagent', 'information_schema') THEN
                    CASE WHEN CASE
            WHEN sn.schema_name = ANY('{information_schema}')
                THEN false
            ELSE true END THEN 'D' ELSE 'O' END
                ELSE 'N'
            END AS catalog_level
        FROM (
            SELECT
            proowner::regrole::text function_owner,
                CASE
                WHEN t.typname IN ('trigger', 'event_trigger') THEN 'trigger_function'
                ELSE 'function' END::text AS obj_type, p.proname AS obj_name,
            ':schema.'|| n.oid || ':/' || n.nspname || '/' || case when t.typname = 'trigger' then ':trigger_function.' else ':function.' end || p.oid ||':/' || p.proname AS obj_path, n.nspname AS schema_name
,
            CASE WHEN t.typname IN ('trigger', 'event_trigger') THEN True ELSE True END AS show_node,
            pg_catalog.pg_get_function_identity_arguments(p.oid) AS other_info
            from pg_catalog.pg_proc p
            left join pg_catalog.pg_namespace n on p.pronamespace = n.oid
            left join pg_catalog.pg_type t on p.prorettype = t.oid
            WHERE (CASE
            WHEN n.nspname = ANY('{information_schema}')
                THEN false
            ELSE true END) AND NOT p.proisagg


        ) sn
        where 1=1 --lower(sn.obj_name) like '%test12345%'
        AND NOT (sn.schema_name IN ('pg_catalog', 'pgagent', 'information_schema'))
        AND (sn.schema_name IS NOT NULL AND sn.schema_name NOT LIKE 'pg\_%')
        and function_owner <> 'appuser'
        ORDER BY 1, 2, 3