CREATE OR REPLACE FUNCTION fun1(arg1 numeric, arg2 numeric)
  RETURNS numeric
LANGUAGE plpgsql
AS $$
DECLARE
    -- <declare variabls>
BEGIN
    BEGIN
        -- <insert status record>
    END;

    -- <function body>

    BEGIN
        -- <update status record>
    END;
END;
$$;

Start Function -> insert record to db -> commit -> run function body -> commit -> End function