对于大型表，示例化视图似乎是最简单的选择。
在触发器功能中刷新视图，你可以使用concurrently选项（见下面的注解）。

create materialized view stuff_dict as 
    select distinct stuff
    from foo;

create or replace function refresh_stuff_dict()
returns trigger language plpgsql
as $$
begin
    refresh materialized view /*concurrently*/ stuff_dict;
    return null;
end $$;

create trigger refresh_stuff_dict
after insert or update or delete or truncate
on foo for each statement 
execute procedure refresh_stuff_dict();

虽然实体化视图的解决方案很简单，但当表foo频繁修改时，它可能不是最佳的。在这种情况下，使用表作为字典。索引会很有帮助。

create table stuff_dict as 
    select distinct stuff
    from foo;

create index on stuff_dict(stuff);

触发器函数更为复杂，应该在插入/更新/删除之后为每一行触发：

create or replace function refresh_stuff_dict()
returns trigger language plpgsql
as $$
declare
    do_insert boolean := tg_op = 'INSERT' or tg_op = 'UPDATE' and new.stuff <> old.stuff;
    do_delete boolean := tg_op = 'DELETE' or tg_op = 'UPDATE' and new.stuff <> old.stuff;
begin
    if do_insert and not exists (select 1 from stuff_dict where stuff = new.stuff) then
        insert into stuff_dict values(new.stuff);
    end if;
    if do_delete and not exists (select 1 from foo where stuff = old.stuff) then
        delete from stuff_dict
        where stuff = old.stuff;
    end if;
    return case tg_op when 'DELETE' then old else new end;
end $$;

create trigger refresh_stuff_dict
after insert or update or delete
on foo for each row
execute procedure refresh_stuff_dict();