sp help text in postgresql
SELECT n.nspname AS schema
,proname AS fname
,proargnames AS args
,t.typname AS return_type
,d.description
,pg_get_functiondef(p.oid) as definition
-- ,CASE WHEN NOT p.proisagg THEN pg_get_functiondef(p.oid)
-- ELSE 'pg_get_functiondef() can''t be used with aggregate functions'
-- END as definition
FROM pg_proc p
JOIN pg_type t
ON p.prorettype = t.oid
LEFT OUTER
JOIN pg_description d
ON p.oid = d.objoid
LEFT OUTER
JOIN pg_namespace n
ON n.oid = p.pronamespace
WHERE NOT p.proisagg
AND n.nspname~'<$SCHEMA_NAME_PATTERN>'
AND proname~'<$FUNCTION_NAME_PATTERN>'