Создаем view:

   CREATE OR REPLACE VIEW funcsource as
      SELECT '--\012create or replace function ' ||
         n.nspname::text || '.'::text || p.proname::text  ||
         '('::text || oidvectortypes(p.proargtypes) || ')\012'::text ||
         'returns ' || t.typname || ' as \'\012' ||
         p.prosrc || '  \'\012' ||
         'language \'' || l.lanname || ' \';\012' as func_source,
         proname as function, nspname as schema, t.typname as rettype,
         oidvectortypes(p.proargtypes) as args, l.lanname as language
      FROM pg_proc p, pg_type t, pg_namespace n, pg_language l
      WHERE p.prorettype = t.oid AND p.pronamespace = n.oid AND p.prolang = l.oid
     AND l.lanname <> 'c' AND l.lanname <> 'internal'  ;

Сохраняем исходные коды функций в файл:
    psql -Atc "select func_source from funcsource;" > functions.out

URL: http://www.sai.msu.su/~megera/oddmuse/index.cgi/pgsql_tips
Обсуждается: https://www.opennet.ru/tips/info/829.shtml